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[patch] Avoid generating warnings for -O2 -Wunreachable-code
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[patch] Avoid generating warnings for -O2 -Wunreachable-code
by Eric Fisher
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Hi,
This patch will avoid generating warnings for -O2 -Wunreachable-code, and has been tested on my machine. Also two test cases need be modified. Is it OK? Regards, Eric 2009-11-04 Eric Fisher <joefoxreal@...> * gcc/tree-ssa-loop-ivcanon.c: Set the statement locations as UNKNOW_LOCATION to avoid generating warnings for -Wunreachable-code. * gcc.dg/Wunreachable-2.c: Remove xfail from dg-bogus. * gcc.dg/Wunreachable-8.c: Remove xfail from dg-bogus. Index: tree-ssa-loop-ivcanon.c =================================================================== --- tree-ssa-loop-ivcanon.c (revision 153584) +++ tree-ssa-loop-ivcanon.c (working copy) @@ -414,6 +414,24 @@ try_unroll_loop_completely (struct loop VEC_free (edge, heap, to_remove); free (wont_exit); free_original_copy_tables (); + + /* The original loop body will be removed later. + Set the statement locations as UNKNOW_LOCATION to + avoid generating warnings for -Wunreachable-code. */ + unsigned n = loop->num_nodes; + basic_block *bbs = get_loop_body (loop); + gcc_assert (n > 1); + gcc_assert (bbs[0] == loop->header); + for (i = 1; i < n; i++) + { + gimple_stmt_iterator gsi; + for (gsi = gsi_start_bb (bbs[i]); !gsi_end_p (gsi); gsi_next (&gsi)) + { + gimple stmt = gsi_stmt (gsi); + gimple_set_location (stmt, UNKNOWN_LOCATION); + } + } + free (bbs); } cond = last_stmt (exit->src); Index: testsuite/gcc.dg/Wunreachable-2.c =================================================================== --- testsuite/gcc.dg/Wunreachable-2.c (revision 153584) +++ testsuite/gcc.dg/Wunreachable-2.c (working copy) @@ -9,8 +9,8 @@ void bar (void) { int i; - for (i = 0; i < 2; i++) /* { dg-bogus "will never be executed" "" { xfail *-*-* } } */ - if (! foo (a[i])) /* { dg-bogus "will never be executed" "" { xfail *-*-* } } */ + for (i = 0; i < 2; i++) /* { dg-bogus "will never be executed" } */ + if (! foo (a[i])) /* { dg-bogus "will never be executed" } */ return; baz (); /* { dg-bogus "will never be executed" } */ Index: testsuite/gcc.dg/Wunreachable-8.c =================================================================== --- testsuite/gcc.dg/Wunreachable-8.c (revision 153584) +++ testsuite/gcc.dg/Wunreachable-8.c (working copy) @@ -4,9 +4,9 @@ float Factorial(float X) { float val = 1.0; int k,j; - for (k=1; k < 5; k++) /* { dg-bogus "will never be executed" "" { xfail *-*-* } } */ + for (k=1; k < 5; k++) /* { dg-bogus "will never be executed" } */ { - val += 1.0; /* { dg-bogus "will never be executed" "" { xfail *-*-* } } */ + val += 1.0; /* { dg-bogus "will never be executed" } */ } return (val); /* { dg-bogus "will never be executed" } */ } ------- make check-gcc, before patched -------- XPASS: gcc.dg/Warray-bounds.c (test for warnings, line 59) XPASS: gcc.dg/Warray-bounds.c (test for warnings, line 65) XPASS: gcc.dg/Wunreachable-8.c (test for bogus messages, line 7) XPASS: gcc.dg/guality/example.c -O0 execution test XPASS: gcc.dg/guality/pr41353-1.c -O0 line 28 j == 28 + 37 XPASS: gcc.dg/guality/pr41447-1.c -O0 execution test XPASS: gcc.dg/guality/pr41616-1.c -O0 execution test XPASS: gcc.dg/struct/wo_prof_array_through_pointer.c scan-ipa-dump ipa_struct_reorg "Number of structures to transform is 1" FAIL: gcc.dg/pr34668-1.c (internal compiler error) FAIL: gcc.dg/pr34668-1.c (test for excess errors) FAIL: gcc.dg/struct/wo_prof_double_malloc.c (internal compiler error) FAIL: gcc.dg/struct/wo_prof_double_malloc.c (test for excess errors) FAIL: gcc.target/i386/avx-vmovntdq-256-1.c (test for excess errors) FAIL: gcc.target/i386/avx-vmovntpd-256-1.c (test for excess errors) FAIL: gcc.target/i386/avx-vmovntps-256-1.c (test for excess errors) === gcc Summary === # of expected passes 60156 # of unexpected failures 7 # of unexpected successes 8 # of expected failures 239 # of unresolved testcases 4 # of unsupported tests 597 ------- make check-gcc, after patched -------- XPASS: gcc.dg/Warray-bounds.c (test for warnings, line 59) XPASS: gcc.dg/Warray-bounds.c (test for warnings, line 65) XPASS: gcc.dg/guality/example.c -O0 execution test XPASS: gcc.dg/guality/pr41353-1.c -O0 line 28 j == 28 + 37 XPASS: gcc.dg/guality/pr41447-1.c -O0 execution test XPASS: gcc.dg/guality/pr41616-1.c -O0 execution test XPASS: gcc.dg/struct/wo_prof_array_through_pointer.c scan-ipa-dump ipa_struct_reorg "Number of structures to transform is 1" FAIL: gcc.dg/pr34668-1.c (internal compiler error) FAIL: gcc.dg/pr34668-1.c (test for excess errors) FAIL: gcc.dg/struct/wo_prof_double_malloc.c (internal compiler error) FAIL: gcc.dg/struct/wo_prof_double_malloc.c (test for excess errors) FAIL: gcc.target/i386/avx-vmovntdq-256-1.c (test for excess errors) FAIL: gcc.target/i386/avx-vmovntpd-256-1.c (test for excess errors) FAIL: gcc.target/i386/avx-vmovntps-256-1.c (test for excess errors) === gcc Summary === # of expected passes 60160 # of unexpected failures 7 # of unexpected successes 7 # of expected failures 236 # of unresolved testcases 4 # of unsupported tests 597 /media/E/svn-gcc/build-trunk/gcc/xgcc version 4.5.0 20091027 (experimental) (GCC) |
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Re: [patch] Avoid generating warnings for -O2 -Wunreachable-code
by Jakub Jelinek
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On Wed, Nov 04, 2009 at 01:37:50PM +0800, Eric Fisher wrote:
> This patch will avoid generating warnings for -O2 -Wunreachable-code, > and has been tested on my machine. Also two test cases need be > modified. This doesn't look like a good idea, while you get rid of an unwanted warning, you also make the code less debuggable. > 2009-11-04 Eric Fisher <joefoxreal@...> > > * gcc/tree-ssa-loop-ivcanon.c: Set the statement locations as > UNKNOW_LOCATION to avoid generating warnings for -Wunreachable-code. > * gcc.dg/Wunreachable-2.c: Remove xfail from dg-bogus. > * gcc.dg/Wunreachable-8.c: Remove xfail from dg-bogus. Jakub |
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Re: [patch] Avoid generating warnings for -O2 -Wunreachable-code
by Eric Fisher
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2009/11/4 Jakub Jelinek <jakub@...>:
> On Wed, Nov 04, 2009 at 01:37:50PM +0800, Eric Fisher wrote: >> This patch will avoid generating warnings for -O2 -Wunreachable-code, >> and has been tested on my machine. Also two test cases need be >> modified. > > This doesn't look like a good idea, while you get rid of an unwanted > warning, you also make the code less debuggable. Hmm. But these code is going to be removed after completely unrolling by cleanup_tree_cfg, so it has nothing to do with debugging. Thanks, Eric |
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Re: [patch] Avoid generating warnings for -O2 -Wunreachable-code
by Richard Guenther-2
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On Wed, Nov 4, 2009 at 7:49 AM, Eric Fisher <joefoxreal@...> wrote:
> 2009/11/4 Jakub Jelinek <jakub@...>: >> On Wed, Nov 04, 2009 at 01:37:50PM +0800, Eric Fisher wrote: >>> This patch will avoid generating warnings for -O2 -Wunreachable-code, >>> and has been tested on my machine. Also two test cases need be >>> modified. >> >> This doesn't look like a good idea, while you get rid of an unwanted >> warning, you also make the code less debuggable. > > Hmm. But these code is going to be removed after completely unrolling > by cleanup_tree_cfg, so it has nothing to do with debugging. -Wunreachable-code is seriously broken, I suggest to remove its implementation completely. Richard. |
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Re: [patch] Avoid generating warnings for -O2 -Wunreachable-code
by Eric Fisher
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2009/11/4 Richard Guenther <richard.guenther@...>:
> -Wunreachable-code is seriously broken, I suggest to remove its > implementation completely. > > Richard. > I have no idea about this. At least, we shouldn't count on gcc emiting correct warnings of -Wunreachable-code when it does optimization. So the testcases should only test flag -Wunreachable-code with -O0. Thus, one solution is just to modify the testsuite. If we plan don't support -Wunreachable-code any more, here is a patch. Index: doc/invoke.texi =================================================================== --- doc/invoke.texi (revision 153929) +++ doc/invoke.texi (working copy) @@ -259,7 +259,7 @@ Objective-C and Objective-C++ Dialects}. -Wstrict-overflow -Wstrict-overflow=@var{n} @gol -Wswitch -Wswitch-default -Wswitch-enum -Wsync-nand @gol -Wsystem-headers -Wtrigraphs -Wtype-limits -Wundef -Wuninitialized @gol --Wunknown-pragmas -Wno-pragmas -Wunreachable-code @gol +-Wunknown-pragmas -Wno-pragmas @gol -Wunsuffixed-float-constants -Wunused -Wunused-function @gol -Wunused-label -Wunused-parameter -Wno-unused-result -Wunused-value -Wunused-variable @gol -Wvariadic-macros -Wvla @gol @@ -4188,29 +4188,6 @@ cases where multiple declaration is vali @opindex Wno-nested-externs Warn if an @code{extern} declaration is encountered within a function. -@item -Wunreachable-code -@opindex Wunreachable-code -@opindex Wno-unreachable-code -Warn if the compiler detects that code will never be executed. - -This option is intended to warn when the compiler detects that at -least a whole line of source code will never be executed, because -some condition is never satisfied or because it is after a -procedure that never returns. - -It is possible for this option to produce a warning even though there -are circumstances under which part of the affected line can be executed, -so care should be taken when removing apparently-unreachable code. - -For instance, when a function is inlined, a warning may mean that the -line is unreachable in only one inlined copy of the function. - -This option is not made part of @option{-Wall} because in a debugging -version of a program there is often substantial code which checks -correct functioning of the program and is, hopefully, unreachable -because the program does work. Another common use of unreachable -code is to provide behavior which is selectable at compile-time. - @item -Winline @opindex Winline @opindex Wno-inline Index: testsuite/gcc.dg/Wunreachable-1.c =================================================================== --- testsuite/gcc.dg/Wunreachable-1.c (revision 153929) +++ testsuite/gcc.dg/Wunreachable-1.c (working copy) @@ -1,24 +0,0 @@ -/* { dg-do compile } */ -/* { dg-options "-O2 -Wunreachable-code" } */ - -extern void foo (void); -extern void baz (void); - -void bar (int i) -{ - if (i < 2) - { - baz (); - return; - } - else - { - if (i >= 4 && i <= 5) - foo (); - return; - } - - baz (); /* { dg-warning "will never be executed" "" } */ - baz (); - baz (); -} Index: testsuite/gcc.dg/Wunreachable-5.c =================================================================== --- testsuite/gcc.dg/Wunreachable-5.c (revision 153929) +++ testsuite/gcc.dg/Wunreachable-5.c (working copy) @@ -1,17 +0,0 @@ -/* PR c/10175 */ - -/* { dg-do compile } */ -/* { dg-options "-Wunreachable-code" } */ - -int value; - -int main(void) -{ - if (0) - value = 0; /* { dg-warning "will never be executed" "" } */ - else - value = 1; - - return 0; -} - Index: testsuite/gcc.dg/Wunreachable-2.c =================================================================== --- testsuite/gcc.dg/Wunreachable-2.c (revision 153929) +++ testsuite/gcc.dg/Wunreachable-2.c (working copy) @@ -1,19 +0,0 @@ -/* { dg-do compile } */ -/* { dg-options "-O2 -Wunreachable-code" } */ - -extern int foo (const char *); -extern void baz (void); -const char *a[] = { "one", "two" }; - -void bar (void) -{ - int i; - - for (i = 0; i < 2; i++) /* { dg-bogus "will never be executed" "" { xfail *-*-* } } */ - if (! foo (a[i])) /* { dg-bogus "will never be executed" "" { xfail *-*-* } } */ - return; - - baz (); /* { dg-bogus "will never be executed" } */ - baz (); - baz (); -} Index: testsuite/gcc.dg/Wunreachable-6.c =================================================================== --- testsuite/gcc.dg/Wunreachable-6.c (revision 153929) +++ testsuite/gcc.dg/Wunreachable-6.c (working copy) @@ -1,21 +0,0 @@ -/* PR c/11370 */ -/* { dg-do compile } */ -/* { dg-options "-Wunreachable-code" } */ - -extern int printf (const char *, ...); -extern void exit (int); - -int main(int argc, char *argv[]) -{ - if (argc != 1) - exit(1); - - { - int ix; /* { dg-bogus "will never be executed" } */ - ix = printf("hello\n"); - printf("%d\n", ix); - } - - return 0; -} - Index: testsuite/gcc.dg/pr12603.c =================================================================== --- testsuite/gcc.dg/pr12603.c (revision 153929) +++ testsuite/gcc.dg/pr12603.c (working copy) @@ -1,6 +1,6 @@ /* PR 12603: No return statement warning on function that never returns with -O3. */ /* { dg-do compile } */ -/* { dg-options "-O3 -Wall -Wextra -Wreturn-type -Wunreachable-code" } */ +/* { dg-options "-O3 -Wall -Wextra -Wreturn-type" } */ int this_function_never_returns () { Index: testsuite/gcc.dg/Wunreachable-3.c =================================================================== --- testsuite/gcc.dg/Wunreachable-3.c (revision 153929) +++ testsuite/gcc.dg/Wunreachable-3.c (working copy) @@ -1,17 +0,0 @@ -/* PR c/10175 */ -/* { dg-do compile } */ -/* { dg-options "-Wunreachable-code" } */ - -int i,j; -int main(void) -{ - if (0) { - i = 0; /* { dg-warning "will never be executed" "" } */ - j = 0; - } else { - i = 1; - j = 1; - } - - return 0; -} Index: testsuite/gcc.dg/Wunreachable-7.c =================================================================== --- testsuite/gcc.dg/Wunreachable-7.c (revision 153929) +++ testsuite/gcc.dg/Wunreachable-7.c (working copy) @@ -1,21 +0,0 @@ -/* PR c/11370 */ -/* { dg-do compile } */ -/* { dg-options "-O2 -Wunreachable-code" } */ - -extern int printf (const char *, ...); -extern void exit (int); - -int main(int argc, char *argv[]) -{ - if (argc != 1) - exit(1); - - { - int ix; /* { dg-bogus "will never be executed" } */ - ix = printf("hello\n"); - printf("%d\n", ix); - } - - return 0; -} - Index: testsuite/gcc.dg/20041231-1.c =================================================================== --- testsuite/gcc.dg/20041231-1.c (revision 153929) +++ testsuite/gcc.dg/20041231-1.c (working copy) @@ -1,15 +0,0 @@ -/* PR17544 Incorrect -Wunreachable-code warning - Origin: Giovanni Bajo - - In C99 we append a "return 0;" when finishing a function, but it was - not given a source location. The gimplifier thinks a return statement - needs a locus so it would add one, making the compiler generated code - visible to the unreachable code warning. */ - -/* { dg-do compile } */ -/* { dg-options "-std=c99 -O -Wunreachable-code" } */ - -int main (void) // 1 -{ // 2 - return 0; // 3 -} // 4 Index: testsuite/gcc.dg/Wunreachable-4.c =================================================================== --- testsuite/gcc.dg/Wunreachable-4.c (revision 153929) +++ testsuite/gcc.dg/Wunreachable-4.c (working copy) @@ -1,12 +0,0 @@ -/* PR middle-end/10336 */ -/* { dg-options "-Wunreachable-code" } */ - -void foo(int i) -{ - switch(i) { - case 0: - break; - case 1: - break; - } -} Index: testsuite/gcc.dg/Wunreachable-8.c =================================================================== --- testsuite/gcc.dg/Wunreachable-8.c (revision 153929) +++ testsuite/gcc.dg/Wunreachable-8.c (working copy) @@ -1,20 +0,0 @@ -/* { dg-do compile } */ -/* { dg-options "-O2 -Wunreachable-code" } */ -float Factorial(float X) -{ - float val = 1.0; - int k,j; - for (k=1; k < 5; k++) /* { dg-bogus "will never be executed" "" { xfail *-*-* } } */ - { - val += 1.0; /* { dg-bogus "will never be executed" "" { xfail *-*-* } } */ - } - return (val); /* { dg-bogus "will never be executed" } */ -} - -int main (void) -{ - float result; - result=Factorial(2.1); - return (0); -} - Index: common.opt =================================================================== --- common.opt (revision 153929) +++ common.opt (working copy) @@ -200,10 +200,6 @@ Wuninitialized Common Var(warn_uninitialized) Init(-1) Warning Warn about uninitialized automatic variables -Wunreachable-code -Common Var(warn_notreached) Warning -Warn about code that will never be executed - Wunused Common Var(warn_unused) Init(0) Warning Enable all -Wunused- warnings Index: tree-cfg.c =================================================================== --- tree-cfg.c (revision 153929) +++ tree-cfg.c (working copy) @@ -1760,7 +1760,6 @@ static void remove_bb (basic_block bb) { gimple_stmt_iterator i; - source_location loc = UNKNOWN_LOCATION; if (dump_file) { @@ -1830,24 +1829,9 @@ remove_bb (basic_block bb) i = gsi_last_bb (bb); else gsi_prev (&i); - - /* Don't warn for removed gotos. Gotos are often removed due to - jump threading, thus resulting in bogus warnings. Not great, - since this way we lose warnings for gotos in the original - program that are indeed unreachable. */ - if (gimple_code (stmt) != GIMPLE_GOTO - && gimple_has_location (stmt)) - loc = gimple_location (stmt); } } - /* If requested, give a warning that the first statement in the - block is unreachable. We walk statements backwards in the - loop above, so the last statement we process is the first statement - in the block. */ - if (loc > BUILTINS_LOCATION && LOCATION_LINE (loc) > 0) - warning_at (loc, OPT_Wunreachable_code, "will never be executed"); - remove_phi_nodes_and_edges_for_unreachable_block (bb); bb->il.gimple = NULL; } |
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Re: [patch] Avoid generating warnings for -O2 -Wunreachable-code
by Richard Guenther-2
::
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On Thu, Nov 5, 2009 at 10:38 AM, Eric Fisher <joefoxreal@...> wrote:
> 2009/11/4 Richard Guenther <richard.guenther@...>: > >> -Wunreachable-code is seriously broken, I suggest to remove its >> implementation completely. >> >> Richard. >> > > I have no idea about this. At least, we shouldn't count on gcc emiting > correct warnings of -Wunreachable-code when it does optimization. So > the testcases should only test flag -Wunreachable-code with -O0. Thus, > one solution is just to modify the testsuite. > > If we plan don't support -Wunreachable-code any more, here is a patch. The patch should retain -Wunreachable-code as a no-op for backward compatibility. And it needs a changelog ;) The patch is ok to apply in a week if nobody raises serious objections. Thanks, Richard. > Index: doc/invoke.texi > =================================================================== > --- doc/invoke.texi (revision 153929) > +++ doc/invoke.texi (working copy) > @@ -259,7 +259,7 @@ Objective-C and Objective-C++ Dialects}. > -Wstrict-overflow -Wstrict-overflow=@var{n} @gol > -Wswitch -Wswitch-default -Wswitch-enum -Wsync-nand @gol > -Wsystem-headers -Wtrigraphs -Wtype-limits -Wundef -Wuninitialized @gol > --Wunknown-pragmas -Wno-pragmas -Wunreachable-code @gol > +-Wunknown-pragmas -Wno-pragmas @gol > -Wunsuffixed-float-constants -Wunused -Wunused-function @gol > -Wunused-label -Wunused-parameter -Wno-unused-result -Wunused-value > -Wunused-variable @gol > -Wvariadic-macros -Wvla @gol > @@ -4188,29 +4188,6 @@ cases where multiple declaration is vali > @opindex Wno-nested-externs > Warn if an @code{extern} declaration is encountered within a function. > > -@item -Wunreachable-code > -@opindex Wunreachable-code > -@opindex Wno-unreachable-code > -Warn if the compiler detects that code will never be executed. > - > -This option is intended to warn when the compiler detects that at > -least a whole line of source code will never be executed, because > -some condition is never satisfied or because it is after a > -procedure that never returns. > - > -It is possible for this option to produce a warning even though there > -are circumstances under which part of the affected line can be executed, > -so care should be taken when removing apparently-unreachable code. > - > -For instance, when a function is inlined, a warning may mean that the > -line is unreachable in only one inlined copy of the function. > - > -This option is not made part of @option{-Wall} because in a debugging > -version of a program there is often substantial code which checks > -correct functioning of the program and is, hopefully, unreachable > -because the program does work. Another common use of unreachable > -code is to provide behavior which is selectable at compile-time. > - > @item -Winline > @opindex Winline > @opindex Wno-inline > Index: testsuite/gcc.dg/Wunreachable-1.c > =================================================================== > --- testsuite/gcc.dg/Wunreachable-1.c (revision 153929) > +++ testsuite/gcc.dg/Wunreachable-1.c (working copy) > @@ -1,24 +0,0 @@ > -/* { dg-do compile } */ > -/* { dg-options "-O2 -Wunreachable-code" } */ > - > -extern void foo (void); > -extern void baz (void); > - > -void bar (int i) > -{ > - if (i < 2) > - { > - baz (); > - return; > - } > - else > - { > - if (i >= 4 && i <= 5) > - foo (); > - return; > - } > - > - baz (); /* { dg-warning "will never be executed" "" } */ > - baz (); > - baz (); > -} > Index: testsuite/gcc.dg/Wunreachable-5.c > =================================================================== > --- testsuite/gcc.dg/Wunreachable-5.c (revision 153929) > +++ testsuite/gcc.dg/Wunreachable-5.c (working copy) > @@ -1,17 +0,0 @@ > -/* PR c/10175 */ > - > -/* { dg-do compile } */ > -/* { dg-options "-Wunreachable-code" } */ > - > -int value; > - > -int main(void) > -{ > - if (0) > - value = 0; /* { dg-warning "will never be executed" "" } */ > - else > - value = 1; > - > - return 0; > -} > - > Index: testsuite/gcc.dg/Wunreachable-2.c > =================================================================== > --- testsuite/gcc.dg/Wunreachable-2.c (revision 153929) > +++ testsuite/gcc.dg/Wunreachable-2.c (working copy) > @@ -1,19 +0,0 @@ > -/* { dg-do compile } */ > -/* { dg-options "-O2 -Wunreachable-code" } */ > - > -extern int foo (const char *); > -extern void baz (void); > -const char *a[] = { "one", "two" }; > - > -void bar (void) > -{ > - int i; > - > - for (i = 0; i < 2; i++) /* { dg-bogus "will never be executed" "" > { xfail *-*-* } } */ > - if (! foo (a[i])) /* { dg-bogus "will never be executed" "" { > xfail *-*-* } } */ > - return; > - > - baz (); /* { dg-bogus "will never be executed" } */ > - baz (); > - baz (); > -} > Index: testsuite/gcc.dg/Wunreachable-6.c > =================================================================== > --- testsuite/gcc.dg/Wunreachable-6.c (revision 153929) > +++ testsuite/gcc.dg/Wunreachable-6.c (working copy) > @@ -1,21 +0,0 @@ > -/* PR c/11370 */ > -/* { dg-do compile } */ > -/* { dg-options "-Wunreachable-code" } */ > - > -extern int printf (const char *, ...); > -extern void exit (int); > - > -int main(int argc, char *argv[]) > -{ > - if (argc != 1) > - exit(1); > - > - { > - int ix; /* { dg-bogus "will never be executed" } */ > - ix = printf("hello\n"); > - printf("%d\n", ix); > - } > - > - return 0; > -} > - > Index: testsuite/gcc.dg/pr12603.c > =================================================================== > --- testsuite/gcc.dg/pr12603.c (revision 153929) > +++ testsuite/gcc.dg/pr12603.c (working copy) > @@ -1,6 +1,6 @@ > /* PR 12603: No return statement warning on function that never > returns with -O3. */ > /* { dg-do compile } */ > -/* { dg-options "-O3 -Wall -Wextra -Wreturn-type -Wunreachable-code" } */ > +/* { dg-options "-O3 -Wall -Wextra -Wreturn-type" } */ > int > this_function_never_returns () > { > Index: testsuite/gcc.dg/Wunreachable-3.c > =================================================================== > --- testsuite/gcc.dg/Wunreachable-3.c (revision 153929) > +++ testsuite/gcc.dg/Wunreachable-3.c (working copy) > @@ -1,17 +0,0 @@ > -/* PR c/10175 */ > -/* { dg-do compile } */ > -/* { dg-options "-Wunreachable-code" } */ > - > -int i,j; > -int main(void) > -{ > - if (0) { > - i = 0; /* { dg-warning "will never be executed" "" } */ > - j = 0; > - } else { > - i = 1; > - j = 1; > - } > - > - return 0; > -} > Index: testsuite/gcc.dg/Wunreachable-7.c > =================================================================== > --- testsuite/gcc.dg/Wunreachable-7.c (revision 153929) > +++ testsuite/gcc.dg/Wunreachable-7.c (working copy) > @@ -1,21 +0,0 @@ > -/* PR c/11370 */ > -/* { dg-do compile } */ > -/* { dg-options "-O2 -Wunreachable-code" } */ > - > -extern int printf (const char *, ...); > -extern void exit (int); > - > -int main(int argc, char *argv[]) > -{ > - if (argc != 1) > - exit(1); > - > - { > - int ix; /* { dg-bogus "will never be executed" } */ > - ix = printf("hello\n"); > - printf("%d\n", ix); > - } > - > - return 0; > -} > - > Index: testsuite/gcc.dg/20041231-1.c > =================================================================== > --- testsuite/gcc.dg/20041231-1.c (revision 153929) > +++ testsuite/gcc.dg/20041231-1.c (working copy) > @@ -1,15 +0,0 @@ > -/* PR17544 Incorrect -Wunreachable-code warning > - Origin: Giovanni Bajo > - > - In C99 we append a "return 0;" when finishing a function, but it was > - not given a source location. The gimplifier thinks a return statement > - needs a locus so it would add one, making the compiler generated code > - visible to the unreachable code warning. */ > - > -/* { dg-do compile } */ > -/* { dg-options "-std=c99 -O -Wunreachable-code" } */ > - > -int main (void) // 1 > -{ // 2 > - return 0; // 3 > -} // 4 > Index: testsuite/gcc.dg/Wunreachable-4.c > =================================================================== > --- testsuite/gcc.dg/Wunreachable-4.c (revision 153929) > +++ testsuite/gcc.dg/Wunreachable-4.c (working copy) > @@ -1,12 +0,0 @@ > -/* PR middle-end/10336 */ > -/* { dg-options "-Wunreachable-code" } */ > - > -void foo(int i) > -{ > - switch(i) { > - case 0: > - break; > - case 1: > - break; > - } > -} > Index: testsuite/gcc.dg/Wunreachable-8.c > =================================================================== > --- testsuite/gcc.dg/Wunreachable-8.c (revision 153929) > +++ testsuite/gcc.dg/Wunreachable-8.c (working copy) > @@ -1,20 +0,0 @@ > -/* { dg-do compile } */ > -/* { dg-options "-O2 -Wunreachable-code" } */ > -float Factorial(float X) > -{ > - float val = 1.0; > - int k,j; > - for (k=1; k < 5; k++) /* { dg-bogus "will never be executed" "" { > xfail *-*-* } } */ > - { > - val += 1.0; /* { dg-bogus "will never be executed" "" { xfail > *-*-* } } */ > - } > - return (val); /* { dg-bogus "will never be executed" } */ > -} > - > -int main (void) > -{ > - float result; > - result=Factorial(2.1); > - return (0); > -} > - > Index: common.opt > =================================================================== > --- common.opt (revision 153929) > +++ common.opt (working copy) > @@ -200,10 +200,6 @@ Wuninitialized > Common Var(warn_uninitialized) Init(-1) Warning > Warn about uninitialized automatic variables > > -Wunreachable-code > -Common Var(warn_notreached) Warning > -Warn about code that will never be executed > - > Wunused > Common Var(warn_unused) Init(0) Warning > Enable all -Wunused- warnings > Index: tree-cfg.c > =================================================================== > --- tree-cfg.c (revision 153929) > +++ tree-cfg.c (working copy) > @@ -1760,7 +1760,6 @@ static void > remove_bb (basic_block bb) > { > gimple_stmt_iterator i; > - source_location loc = UNKNOWN_LOCATION; > > if (dump_file) > { > @@ -1830,24 +1829,9 @@ remove_bb (basic_block bb) > i = gsi_last_bb (bb); > else > gsi_prev (&i); > - > - /* Don't warn for removed gotos. Gotos are often removed due to > - jump threading, thus resulting in bogus warnings. Not great, > - since this way we lose warnings for gotos in the original > - program that are indeed unreachable. */ > - if (gimple_code (stmt) != GIMPLE_GOTO > - && gimple_has_location (stmt)) > - loc = gimple_location (stmt); > } > } > > - /* If requested, give a warning that the first statement in the > - block is unreachable. We walk statements backwards in the > - loop above, so the last statement we process is the first statement > - in the block. */ > - if (loc > BUILTINS_LOCATION && LOCATION_LINE (loc) > 0) > - warning_at (loc, OPT_Wunreachable_code, "will never be executed"); > - > remove_phi_nodes_and_edges_for_unreachable_block (bb); > bb->il.gimple = NULL; > } > |
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Re: [patch] Avoid generating warnings for -O2 -Wunreachable-code
by Eric Fisher
::
Rate this Message:
2009/11/5 Richard Guenther <richard.guenther@...>:
> > The patch should retain -Wunreachable-code as a no-op > for backward compatibility. And it needs a changelog ;) > > The patch is ok to apply in a week if nobody raises serious objections. > > Thanks, > Richard. > I have modified the patch to retain the option -Wunreachable-code as a no-op. The patch was tested on my x86 platform. Is it OK? Best regards, Eric 2009-11-06 Eric Fisher <joefoxreal@...> * doc/invoke.texi: Remove the documentation about option -Wunreachable-code. * testsuite/gcc.dg/Wunreachable-1.c: Remove the testcase of -Wunreachable-code. * testsuite/gcc.dg/Wunreachable-2.c: Same to above * testsuite/gcc.dg/Wunreachable-3.c: Same to above * testsuite/gcc.dg/Wunreachable-4.c: Same to above * testsuite/gcc.dg/Wunreachable-5.c: Same to above * testsuite/gcc.dg/Wunreachable-6.c: Same to above * testsuite/gcc.dg/Wunreachable-7.c: Same to above * testsuite/gcc.dg/Wunreachable-8.c: Same to above * testsuite/gcc.dg/20041231-1.c: Same to above * testsuite/gcc.dg/pr12603.c: Remove -Wunreachable-code from dg-options * gcc/common.opt: Change the help string of -Wunreachable-code to indicate no more support. * gcc/tree-cfg.c: Remove the implementation of -Wunreachable-code. Index: doc/invoke.texi =================================================================== --- doc/invoke.texi (revision 153929) +++ doc/invoke.texi (working copy) @@ -259,7 +259,7 @@ Objective-C and Objective-C++ Dialects}. -Wstrict-overflow -Wstrict-overflow=@var{n} @gol -Wswitch -Wswitch-default -Wswitch-enum -Wsync-nand @gol -Wsystem-headers -Wtrigraphs -Wtype-limits -Wundef -Wuninitialized @gol --Wunknown-pragmas -Wno-pragmas -Wunreachable-code @gol +-Wunknown-pragmas -Wno-pragmas @gol -Wunsuffixed-float-constants -Wunused -Wunused-function @gol -Wunused-label -Wunused-parameter -Wno-unused-result -Wunused-value -Wunused-variable @gol -Wvariadic-macros -Wvla @gol @@ -4188,29 +4188,6 @@ cases where multiple declaration is vali @opindex Wno-nested-externs Warn if an @code{extern} declaration is encountered within a function. -@item -Wunreachable-code -@opindex Wunreachable-code -@opindex Wno-unreachable-code -Warn if the compiler detects that code will never be executed. - -This option is intended to warn when the compiler detects that at -least a whole line of source code will never be executed, because -some condition is never satisfied or because it is after a -procedure that never returns. - -It is possible for this option to produce a warning even though there -are circumstances under which part of the affected line can be executed, -so care should be taken when removing apparently-unreachable code. - -For instance, when a function is inlined, a warning may mean that the -line is unreachable in only one inlined copy of the function. - -This option is not made part of @option{-Wall} because in a debugging -version of a program there is often substantial code which checks -correct functioning of the program and is, hopefully, unreachable -because the program does work. Another common use of unreachable -code is to provide behavior which is selectable at compile-time. - @item -Winline @opindex Winline @opindex Wno-inline Index: testsuite/gcc.dg/Wunreachable-1.c =================================================================== --- testsuite/gcc.dg/Wunreachable-1.c (revision 153929) +++ testsuite/gcc.dg/Wunreachable-1.c (working copy) @@ -1,24 +0,0 @@ -/* { dg-do compile } */ -/* { dg-options "-O2 -Wunreachable-code" } */ - -extern void foo (void); -extern void baz (void); - -void bar (int i) -{ - if (i < 2) - { - baz (); - return; - } - else - { - if (i >= 4 && i <= 5) - foo (); - return; - } - - baz (); /* { dg-warning "will never be executed" "" } */ - baz (); - baz (); -} Index: testsuite/gcc.dg/Wunreachable-5.c =================================================================== --- testsuite/gcc.dg/Wunreachable-5.c (revision 153929) +++ testsuite/gcc.dg/Wunreachable-5.c (working copy) @@ -1,17 +0,0 @@ -/* PR c/10175 */ - -/* { dg-do compile } */ -/* { dg-options "-Wunreachable-code" } */ - -int value; - -int main(void) -{ - if (0) - value = 0; /* { dg-warning "will never be executed" "" } */ - else - value = 1; - - return 0; -} - Index: testsuite/gcc.dg/Wunreachable-2.c =================================================================== --- testsuite/gcc.dg/Wunreachable-2.c (revision 153929) +++ testsuite/gcc.dg/Wunreachable-2.c (working copy) @@ -1,19 +0,0 @@ -/* { dg-do compile } */ -/* { dg-options "-O2 -Wunreachable-code" } */ - -extern int foo (const char *); -extern void baz (void); -const char *a[] = { "one", "two" }; - -void bar (void) -{ - int i; - - for (i = 0; i < 2; i++) /* { dg-bogus "will never be executed" "" { xfail *-*-* } } */ - if (! foo (a[i])) /* { dg-bogus "will never be executed" "" { xfail *-*-* } } */ - return; - - baz (); /* { dg-bogus "will never be executed" } */ - baz (); - baz (); -} Index: testsuite/gcc.dg/Wunreachable-6.c =================================================================== --- testsuite/gcc.dg/Wunreachable-6.c (revision 153929) +++ testsuite/gcc.dg/Wunreachable-6.c (working copy) @@ -1,21 +0,0 @@ -/* PR c/11370 */ -/* { dg-do compile } */ -/* { dg-options "-Wunreachable-code" } */ - -extern int printf (const char *, ...); -extern void exit (int); - -int main(int argc, char *argv[]) -{ - if (argc != 1) - exit(1); - - { - int ix; /* { dg-bogus "will never be executed" } */ - ix = printf("hello\n"); - printf("%d\n", ix); - } - - return 0; -} - Index: testsuite/gcc.dg/pr12603.c =================================================================== --- testsuite/gcc.dg/pr12603.c (revision 153932) +++ testsuite/gcc.dg/pr12603.c (working copy) @@ -1,6 +1,6 @@ /* PR 12603: No return statement warning on function that never returns with -O3. */ /* { dg-do compile } */ -/* { dg-options "-O3 -Wall -Wextra -Wreturn-type -Wunreachable-code" } */ +/* { dg-options "-O3 -Wall -Wextra -Wreturn-type" } */ int this_function_never_returns () { Index: testsuite/gcc.dg/Wunreachable-3.c =================================================================== --- testsuite/gcc.dg/Wunreachable-3.c (revision 153929) +++ testsuite/gcc.dg/Wunreachable-3.c (working copy) @@ -1,17 +0,0 @@ -/* PR c/10175 */ -/* { dg-do compile } */ -/* { dg-options "-Wunreachable-code" } */ - -int i,j; -int main(void) -{ - if (0) { - i = 0; /* { dg-warning "will never be executed" "" } */ - j = 0; - } else { - i = 1; - j = 1; - } - - return 0; -} Index: testsuite/gcc.dg/Wunreachable-7.c =================================================================== --- testsuite/gcc.dg/Wunreachable-7.c (revision 153929) +++ testsuite/gcc.dg/Wunreachable-7.c (working copy) @@ -1,21 +0,0 @@ -/* PR c/11370 */ -/* { dg-do compile } */ -/* { dg-options "-O2 -Wunreachable-code" } */ - -extern int printf (const char *, ...); -extern void exit (int); - -int main(int argc, char *argv[]) -{ - if (argc != 1) - exit(1); - - { - int ix; /* { dg-bogus "will never be executed" } */ - ix = printf("hello\n"); - printf("%d\n", ix); - } - - return 0; -} - Index: testsuite/gcc.dg/20041231-1.c =================================================================== --- testsuite/gcc.dg/20041231-1.c (revision 153929) +++ testsuite/gcc.dg/20041231-1.c (working copy) @@ -1,15 +0,0 @@ -/* PR17544 Incorrect -Wunreachable-code warning - Origin: Giovanni Bajo - - In C99 we append a "return 0;" when finishing a function, but it was - not given a source location. The gimplifier thinks a return statement - needs a locus so it would add one, making the compiler generated code - visible to the unreachable code warning. */ - -/* { dg-do compile } */ -/* { dg-options "-std=c99 -O -Wunreachable-code" } */ - -int main (void) // 1 -{ // 2 - return 0; // 3 -} // 4 Index: testsuite/gcc.dg/Wunreachable-4.c =================================================================== --- testsuite/gcc.dg/Wunreachable-4.c (revision 153929) +++ testsuite/gcc.dg/Wunreachable-4.c (working copy) @@ -1,12 +0,0 @@ -/* PR middle-end/10336 */ -/* { dg-options "-Wunreachable-code" } */ - -void foo(int i) -{ - switch(i) { - case 0: - break; - case 1: - break; - } -} Index: testsuite/gcc.dg/Wunreachable-8.c =================================================================== --- testsuite/gcc.dg/Wunreachable-8.c (revision 153929) +++ testsuite/gcc.dg/Wunreachable-8.c (working copy) @@ -1,20 +0,0 @@ -/* { dg-do compile } */ -/* { dg-options "-O2 -Wunreachable-code" } */ -float Factorial(float X) -{ - float val = 1.0; - int k,j; - for (k=1; k < 5; k++) /* { dg-bogus "will never be executed" "" { xfail *-*-* } } */ - { - val += 1.0; /* { dg-bogus "will never be executed" "" { xfail *-*-* } } */ - } - return (val); /* { dg-bogus "will never be executed" } */ -} - -int main (void) -{ - float result; - result=Factorial(2.1); - return (0); -} - Index: common.opt =================================================================== --- common.opt (revision 153929) +++ common.opt (working copy) @@ -202,7 +202,7 @@ Warn about uninitialized automatic varia Wunreachable-code Common Var(warn_notreached) Warning -Warn about code that will never be executed +This option is not supported and just retains here for backword compatibility. Wunused Common Var(warn_unused) Init(0) Warning Index: tree-cfg.c =================================================================== --- tree-cfg.c (revision 153929) +++ tree-cfg.c (working copy) @@ -1760,7 +1760,6 @@ static void remove_bb (basic_block bb) { gimple_stmt_iterator i; - source_location loc = UNKNOWN_LOCATION; if (dump_file) { @@ -1830,24 +1829,9 @@ remove_bb (basic_block bb) i = gsi_last_bb (bb); else gsi_prev (&i); - - /* Don't warn for removed gotos. Gotos are often removed due to - jump threading, thus resulting in bogus warnings. Not great, - since this way we lose warnings for gotos in the original - program that are indeed unreachable. */ - if (gimple_code (stmt) != GIMPLE_GOTO - && gimple_has_location (stmt)) - loc = gimple_location (stmt); } } - /* If requested, give a warning that the first statement in the - block is unreachable. We walk statements backwards in the - loop above, so the last statement we process is the first statement - in the block. */ - if (loc > BUILTINS_LOCATION && LOCATION_LINE (loc) > 0) - warning_at (loc, OPT_Wunreachable_code, "will never be executed"); - remove_phi_nodes_and_edges_for_unreachable_block (bb); bb->il.gimple = NULL; } === gcc Summary === # of expected passes 60290 # of unexpected failures 7 # of unexpected successes 7 # of expected failures 201 # of unresolved testcases 4 # of unsupported tests 610 FAIL: gcc.dg/pr34668-1.c (internal compiler error) FAIL: gcc.dg/pr34668-1.c (test for excess errors) FAIL: gcc.dg/struct/wo_prof_double_malloc.c (internal compiler error) FAIL: gcc.dg/struct/wo_prof_double_malloc.c (test for excess errors) FAIL: gcc.target/i386/avx-vmovntdq-256-1.c (test for excess errors) FAIL: gcc.target/i386/avx-vmovntpd-256-1.c (test for excess errors) FAIL: gcc.target/i386/avx-vmovntps-256-1.c (test for excess errors) XPASS: gcc.dg/Warray-bounds.c (test for warnings, line 59) XPASS: gcc.dg/Warray-bounds.c (test for warnings, line 65) XPASS: gcc.dg/guality/example.c -O0 execution test XPASS: gcc.dg/guality/pr41353-1.c -O0 line 28 j == 28 + 37 XPASS: gcc.dg/guality/pr41447-1.c -O0 execution test XPASS: gcc.dg/guality/pr41616-1.c -O0 execution test XPASS: gcc.dg/struct/wo_prof_array_through_pointer.c scan-ipa-dump ipa_struct_reorg "Number of structures to transform is 1" |
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Re: [patch] Avoid generating warnings for -O2 -Wunreachable-code
by Richard Guenther-2
::
Rate this Message:
On Fri, Nov 6, 2009 at 6:41 AM, Eric Fisher <joefoxreal@...> wrote:
> 2009/11/5 Richard Guenther <richard.guenther@...>: >> >> The patch should retain -Wunreachable-code as a no-op >> for backward compatibility. And it needs a changelog ;) >> >> The patch is ok to apply in a week if nobody raises serious objections. >> >> Thanks, >> Richard. >> > > I have modified the patch to retain the option -Wunreachable-code as a > no-op. The patch was tested on my x86 platform. > > Is it OK? You should remove the flags variable and the option kind > Wunreachable-code > Common Var(warn_notreached) Warning > -Warn about code that will never be executed > +This option is not supported and just retains here for backword compatibility. Thus just Wunreachable-code Common Does nothing. Preserved for backward compatibility. which is the canonical description for backward compatibility options. Please try specifying -Wunreachable-code after that patch, if it ICEs you have to add it to the backward compatibility flag section in opts.c:common_handle_option. The patch is ok with that change if it still passes bootstrap after a week to let people complain. Thanks, Richard. |
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Re: [patch] Avoid generating warnings for -O2 -Wunreachable-code
by Eric Fisher
::
Rate this Message:
2009/11/6 Richard Guenther <richard.guenther@...>:
> > Please try specifying -Wunreachable-code after that patch, > if it ICEs you have to add it to the backward compatibility > flag section in opts.c:common_handle_option. > > The patch is ok with that change if it still passes bootstrap > after a week to let people complain. Hi Richard, thanks for your directions. I have updated the patch and tested it on my machine. Best regards, Eric 2009-11-07 Eric Fisher <joefoxreal@...> * doc/invoke.texi: Remove the documentation about option -Wunreachable-code. * testsuite/gcc.dg/Wunreachable-1.c: Remove the testcase of -Wunreachable-code. * testsuite/gcc.dg/Wunreachable-2.c: Same to above * testsuite/gcc.dg/Wunreachable-3.c: Same to above * testsuite/gcc.dg/Wunreachable-4.c: Same to above * testsuite/gcc.dg/Wunreachable-5.c: Same to above * testsuite/gcc.dg/Wunreachable-6.c: Same to above * testsuite/gcc.dg/Wunreachable-7.c: Same to above * testsuite/gcc.dg/Wunreachable-8.c: Same to above * testsuite/gcc.dg/20041231-1.c: Same to above * testsuite/gcc.dg/pr12603.c: Remove -Wunreachable-code from dg-options * gcc/common.opt (Wunreachable-code): Preserved for backward compatibility. * gcc/tree-cfg.c: Remove the implementation of -Wunreachable-code. * gcc/opts.c (common_handle_option): Add OPT_Wunreachable_code to the backward compatibility flag section Index: doc/invoke.texi =================================================================== --- doc/invoke.texi (revision 153929) +++ doc/invoke.texi (working copy) @@ -259,7 +259,7 @@ Objective-C and Objective-C++ Dialects}. -Wstrict-overflow -Wstrict-overflow=@var{n} @gol -Wswitch -Wswitch-default -Wswitch-enum -Wsync-nand @gol -Wsystem-headers -Wtrigraphs -Wtype-limits -Wundef -Wuninitialized @gol --Wunknown-pragmas -Wno-pragmas -Wunreachable-code @gol +-Wunknown-pragmas -Wno-pragmas @gol -Wunsuffixed-float-constants -Wunused -Wunused-function @gol -Wunused-label -Wunused-parameter -Wno-unused-result -Wunused-value -Wunused-variable @gol -Wvariadic-macros -Wvla @gol @@ -4188,29 +4188,6 @@ cases where multiple declaration is vali @opindex Wno-nested-externs Warn if an @code{extern} declaration is encountered within a function. -@item -Wunreachable-code -@opindex Wunreachable-code -@opindex Wno-unreachable-code -Warn if the compiler detects that code will never be executed. - -This option is intended to warn when the compiler detects that at -least a whole line of source code will never be executed, because -some condition is never satisfied or because it is after a -procedure that never returns. - -It is possible for this option to produce a warning even though there -are circumstances under which part of the affected line can be executed, -so care should be taken when removing apparently-unreachable code. - -For instance, when a function is inlined, a warning may mean that the -line is unreachable in only one inlined copy of the function. - -This option is not made part of @option{-Wall} because in a debugging -version of a program there is often substantial code which checks -correct functioning of the program and is, hopefully, unreachable -because the program does work. Another common use of unreachable -code is to provide behavior which is selectable at compile-time. - @item -Winline @opindex Winline @opindex Wno-inline Index: testsuite/gcc.dg/Wunreachable-1.c =================================================================== --- testsuite/gcc.dg/Wunreachable-1.c (revision 153929) +++ testsuite/gcc.dg/Wunreachable-1.c (working copy) @@ -1,24 +0,0 @@ -/* { dg-do compile } */ -/* { dg-options "-O2 -Wunreachable-code" } */ - -extern void foo (void); -extern void baz (void); - -void bar (int i) -{ - if (i < 2) - { - baz (); - return; - } - else - { - if (i >= 4 && i <= 5) - foo (); - return; - } - - baz (); /* { dg-warning "will never be executed" "" } */ - baz (); - baz (); -} Index: testsuite/gcc.dg/Wunreachable-5.c =================================================================== --- testsuite/gcc.dg/Wunreachable-5.c (revision 153929) +++ testsuite/gcc.dg/Wunreachable-5.c (working copy) @@ -1,17 +0,0 @@ -/* PR c/10175 */ - -/* { dg-do compile } */ -/* { dg-options "-Wunreachable-code" } */ - -int value; - -int main(void) -{ - if (0) - value = 0; /* { dg-warning "will never be executed" "" } */ - else - value = 1; - - return 0; -} - Index: testsuite/gcc.dg/Wunreachable-2.c =================================================================== --- testsuite/gcc.dg/Wunreachable-2.c (revision 153929) +++ testsuite/gcc.dg/Wunreachable-2.c (working copy) @@ -1,19 +0,0 @@ -/* { dg-do compile } */ -/* { dg-options "-O2 -Wunreachable-code" } */ - -extern int foo (const char *); -extern void baz (void); -const char *a[] = { "one", "two" }; - -void bar (void) -{ - int i; - - for (i = 0; i < 2; i++) /* { dg-bogus "will never be executed" "" { xfail *-*-* } } */ - if (! foo (a[i])) /* { dg-bogus "will never be executed" "" { xfail *-*-* } } */ - return; - - baz (); /* { dg-bogus "will never be executed" } */ - baz (); - baz (); -} Index: testsuite/gcc.dg/Wunreachable-6.c =================================================================== --- testsuite/gcc.dg/Wunreachable-6.c (revision 153929) +++ testsuite/gcc.dg/Wunreachable-6.c (working copy) @@ -1,21 +0,0 @@ -/* PR c/11370 */ -/* { dg-do compile } */ -/* { dg-options "-Wunreachable-code" } */ - -extern int printf (const char *, ...); -extern void exit (int); - -int main(int argc, char *argv[]) -{ - if (argc != 1) - exit(1); - - { - int ix; /* { dg-bogus "will never be executed" } */ - ix = printf("hello\n"); - printf("%d\n", ix); - } - - return 0; -} - Index: testsuite/gcc.dg/pr12603.c =================================================================== --- testsuite/gcc.dg/pr12603.c (revision 153932) +++ testsuite/gcc.dg/pr12603.c (working copy) @@ -1,6 +1,6 @@ /* PR 12603: No return statement warning on function that never returns with -O3. */ /* { dg-do compile } */ -/* { dg-options "-O3 -Wall -Wextra -Wreturn-type -Wunreachable-code" } */ +/* { dg-options "-O3 -Wall -Wextra -Wreturn-type" } */ int this_function_never_returns () { Index: testsuite/gcc.dg/Wunreachable-3.c =================================================================== --- testsuite/gcc.dg/Wunreachable-3.c (revision 153929) +++ testsuite/gcc.dg/Wunreachable-3.c (working copy) @@ -1,17 +0,0 @@ -/* PR c/10175 */ -/* { dg-do compile } */ -/* { dg-options "-Wunreachable-code" } */ - -int i,j; -int main(void) -{ - if (0) { - i = 0; /* { dg-warning "will never be executed" "" } */ - j = 0; - } else { - i = 1; - j = 1; - } - - return 0; -} Index: testsuite/gcc.dg/Wunreachable-7.c =================================================================== --- testsuite/gcc.dg/Wunreachable-7.c (revision 153929) +++ testsuite/gcc.dg/Wunreachable-7.c (working copy) @@ -1,21 +0,0 @@ -/* PR c/11370 */ -/* { dg-do compile } */ -/* { dg-options "-O2 -Wunreachable-code" } */ - -extern int printf (const char *, ...); -extern void exit (int); - -int main(int argc, char *argv[]) -{ - if (argc != 1) - exit(1); - - { - int ix; /* { dg-bogus "will never be executed" } */ - ix = printf("hello\n"); - printf("%d\n", ix); - } - - return 0; -} - Index: testsuite/gcc.dg/20041231-1.c =================================================================== --- testsuite/gcc.dg/20041231-1.c (revision 153929) +++ testsuite/gcc.dg/20041231-1.c (working copy) @@ -1,15 +0,0 @@ -/* PR17544 Incorrect -Wunreachable-code warning - Origin: Giovanni Bajo - - In C99 we append a "return 0;" when finishing a function, but it was - not given a source location. The gimplifier thinks a return statement - needs a locus so it would add one, making the compiler generated code - visible to the unreachable code warning. */ - -/* { dg-do compile } */ -/* { dg-options "-std=c99 -O -Wunreachable-code" } */ - -int main (void) // 1 -{ // 2 - return 0; // 3 -} // 4 Index: testsuite/gcc.dg/Wunreachable-4.c =================================================================== --- testsuite/gcc.dg/Wunreachable-4.c (revision 153929) +++ testsuite/gcc.dg/Wunreachable-4.c (working copy) @@ -1,12 +0,0 @@ -/* PR middle-end/10336 */ -/* { dg-options "-Wunreachable-code" } */ - -void foo(int i) -{ - switch(i) { - case 0: - break; - case 1: - break; - } -} Index: testsuite/gcc.dg/Wunreachable-8.c =================================================================== --- testsuite/gcc.dg/Wunreachable-8.c (revision 153929) +++ testsuite/gcc.dg/Wunreachable-8.c (working copy) @@ -1,20 +0,0 @@ -/* { dg-do compile } */ -/* { dg-options "-O2 -Wunreachable-code" } */ -float Factorial(float X) -{ - float val = 1.0; - int k,j; - for (k=1; k < 5; k++) /* { dg-bogus "will never be executed" "" { xfail *-*-* } } */ - { - val += 1.0; /* { dg-bogus "will never be executed" "" { xfail *-*-* } } */ - } - return (val); /* { dg-bogus "will never be executed" } */ -} - -int main (void) -{ - float result; - result=Factorial(2.1); - return (0); -} - Index: opts.c =================================================================== --- opts.c (revision 153929) +++ opts.c (working copy) @@ -2121,6 +2121,7 @@ common_handle_option (size_t scode, cons case OPT_fforce_addr: case OPT_ftree_salias: case OPT_ftree_store_ccp: + case OPT_Wunreachable_code: /* These are no-ops, preserved for backward compatibility. */ break; Index: common.opt =================================================================== --- common.opt (revision 153929) +++ common.opt (working copy) @@ -201,8 +201,8 @@ Common Var(warn_uninitialized) Init(-1) Warn about uninitialized automatic variables Wunreachable-code -Common Var(warn_notreached) Warning -Warn about code that will never be executed +Common +Does nothing. Preserved for backward compatibility. Wunused Common Var(warn_unused) Init(0) Warning Index: tree-cfg.c =================================================================== --- tree-cfg.c (revision 153929) +++ tree-cfg.c (working copy) @@ -1760,7 +1760,6 @@ static void remove_bb (basic_block bb) { gimple_stmt_iterator i; - source_location loc = UNKNOWN_LOCATION; if (dump_file) { @@ -1830,24 +1829,9 @@ remove_bb (basic_block bb) i = gsi_last_bb (bb); else gsi_prev (&i); - - /* Don't warn for removed gotos. Gotos are often removed due to - jump threading, thus resulting in bogus warnings. Not great, - since this way we lose warnings for gotos in the original - program that are indeed unreachable. */ - if (gimple_code (stmt) != GIMPLE_GOTO - && gimple_has_location (stmt)) - loc = gimple_location (stmt); } } - /* If requested, give a warning that the first statement in the - block is unreachable. We walk statements backwards in the - loop above, so the last statement we process is the first statement - in the block. */ - if (loc > BUILTINS_LOCATION && LOCATION_LINE (loc) > 0) - warning_at (loc, OPT_Wunreachable_code, "will never be executed"); - remove_phi_nodes_and_edges_for_unreachable_block (bb); bb->il.gimple = NULL; } |
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