| Message ID | 20160510181929.GE20450@redhat.com |
|---|---|
| State | New |
| Headers | show |
Any comments on this patch? Should I pursue the C++ part? On Tue, May 10, 2016 at 08:19:29PM +0200, Marek Polacek wrote: > Over the years, we got several PRs that suggested to add a warning that would > warn about unreachable statements between `switch (cond)' and the first case. > In some cases our -Wuninitialized warning can detect such a case, but mostly > not. This patch is an attempt to add a proper warning about this peculiar > case. I chose to not warn about declarations between switch and the first > case, because we use that in the codebase and I think this kind of use is > fine. As it's usually the case, some obscure cases cropped up during testing, > this time those were Duff's devices, so I had to go the extra mile to handle > them specially. > > This is a C FE part only; I'd like to hear some feedback first before I plunge > into the C++ FE. > > Bootstrapped/regtested on x86_64-linux, ok for trunk? > > 2016-05-10 Marek Polacek <polacek@redhat.com> > > PR c/49859 > * c.opt (Wswitch-unreachable): New option. > > * c-parser.c: Include tree-iterator.h. > (c_parser_switch_statement): Implement -Wswitch-unreachable warning. > > * doc/invoke.texi: Document -Wswitch-unreachable. > > * gcc.dg/Wjump-misses-init-1.c: Use -Wno-switch-unreachable. > * gcc.dg/nested-func-1.c: Likewise. > * gcc.dg/pr67784-4.c: Likewise. > * gcc.dg/Wswitch-unreachable-1.c: New test. > * gcc.dg/c99-vla-jump-5.c (f): Add dg-warning. > * gcc.dg/switch-warn-1.c (foo1): Likewise. > * c-c++-common/goacc/sb-2.c: Likewise. > * gcc.dg/gomp/block-10.c: Likewise. > * gcc.dg/gomp/block-9.c: Likewise. > * gcc.dg/gomp/target-1.c: Likewise. > * gcc.dg/gomp/target-2.c: Likewise. > * gcc.dg/gomp/taskgroup-1.c: Likewise. > * gcc.dg/gomp/teams-1.c: Likewise. > > diff --git gcc/c-family/c.opt gcc/c-family/c.opt > index bdc6ee0..8b6fdbb 100644 > --- gcc/c-family/c.opt > +++ gcc/c-family/c.opt > @@ -634,6 +634,11 @@ Wswitch-bool > C ObjC C++ ObjC++ Var(warn_switch_bool) Warning Init(1) > Warn about switches with boolean controlling expression. > > +Wswitch-unreachable > +C ObjC C++ ObjC++ Var(warn_switch_unreachable) Warning Init(1) > +Warn about statements between switch's controlling expression and the first > +case. > + > Wtemplates > C++ ObjC++ Var(warn_templates) Warning > Warn on primary template declaration. > diff --git gcc/c/c-parser.c gcc/c/c-parser.c > index 6523c08..bdf8e8e 100644 > --- gcc/c/c-parser.c > +++ gcc/c/c-parser.c > @@ -58,6 +58,7 @@ along with GCC; see the file COPYING3. If not see > #include "c-family/c-indentation.h" > #include "gimple-expr.h" > #include "context.h" > +#include "tree-iterator.h" > > /* We need to walk over decls with incomplete struct/union/enum types > after parsing the whole translation unit. > @@ -5605,7 +5606,30 @@ c_parser_switch_statement (c_parser *parser, bool *if_p) > c_start_case (switch_loc, switch_cond_loc, expr, explicit_cast_p); > save_break = c_break_label; > c_break_label = NULL_TREE; > + location_t first_loc = (c_parser_next_token_is (parser, CPP_OPEN_BRACE) > + ? c_parser_peek_2nd_token (parser)->location > + : c_parser_peek_token (parser)->location); > body = c_parser_c99_block_statement (parser, if_p); > + tree first = expr_first (TREE_CODE (body) == BIND_EXPR > + ? BIND_EXPR_BODY (body) : body); > + /* Statements between `switch' and the first case are never executed. */ > + if (warn_switch_unreachable > + && first != NULL_TREE > + && TREE_CODE (first) != CASE_LABEL_EXPR > + && TREE_CODE (first) != LABEL_EXPR) > + { > + if (TREE_CODE (first) == DECL_EXPR > + && DECL_INITIAL (DECL_EXPR_DECL (first)) == NULL_TREE) > + /* Don't warn for a declaration, but warn for an initialization. */; > + else if (TREE_CODE (first) == GOTO_EXPR > + && TREE_CODE (GOTO_DESTINATION (first)) == LABEL_DECL > + && DECL_ARTIFICIAL (GOTO_DESTINATION (first))) > + /* Don't warn for compiler-generated gotos. These occur in Duff's > + devices, for example. */; > + else > + warning_at (first_loc, OPT_Wswitch_unreachable, > + "statement will never be executed"); > + } > c_finish_case (body, ce.original_type); > if (c_break_label) > { > diff --git gcc/doc/invoke.texi gcc/doc/invoke.texi > index a54a0af..8f9c186 100644 > --- gcc/doc/invoke.texi > +++ gcc/doc/invoke.texi > @@ -297,7 +297,8 @@ Objective-C and Objective-C++ Dialects}. > -Wsuggest-attribute=@r{[}pure@r{|}const@r{|}noreturn@r{|}format@r{]} @gol > -Wsuggest-final-types @gol -Wsuggest-final-methods -Wsuggest-override @gol > -Wmissing-format-attribute -Wsubobject-linkage @gol > --Wswitch -Wswitch-default -Wswitch-enum -Wswitch-bool -Wsync-nand @gol > +-Wswitch -Wswitch-default -Wswitch-enum -Wswitch-bool @gol > +-Wswitch-unreachable -Wsync-nand @gol > -Wsystem-headers -Wtautological-compare -Wtrampolines -Wtrigraphs @gol > -Wtype-limits -Wundef @gol > -Wuninitialized -Wunknown-pragmas -Wunsafe-loop-optimizations @gol > @@ -4135,6 +4136,39 @@ switch ((int) (a == 4)) > @end smallexample > This warning is enabled by default for C and C++ programs. > > +@item -Wswitch-unreachable > +@opindex Wswitch-unreachable > +@opindex Wno-switch-unreachable > +Warn whenever a @code{switch} statement contains statements between the > +controlling expression and the first case label, which will never be > +executed. For example: > +@smallexample > +@group > +switch (cond) > + @{ > + i = 15; > + @dots{} > + case 5: > + @dots{} > + @} > +@end group > +@end smallexample > +@option{-Wswitch-unreachable} will not warn if the statement between the > +controlling expression and the first case label is just a declaration: > +@smallexample > +@group > +switch (cond) > + @{ > + int i; > + @dots{} > + case 5: > + i = 5; > + @dots{} > + @} > +@end group > +@end smallexample > +This warning is enabled by default for C and C++ programs. > + > @item -Wsync-nand @r{(C and C++ only)} > @opindex Wsync-nand > @opindex Wno-sync-nand > diff --git gcc/testsuite/c-c++-common/goacc/sb-2.c gcc/testsuite/c-c++-common/goacc/sb-2.c > index a6760ec..e986af3 100644 > --- gcc/testsuite/c-c++-common/goacc/sb-2.c > +++ gcc/testsuite/c-c++-common/goacc/sb-2.c > @@ -4,19 +4,19 @@ void foo(int i) > { > switch (i) // { dg-error "invalid entry to OpenACC structured block" } > { > - #pragma acc parallel > + #pragma acc parallel // { dg-warning "statement will never be executed" } > { case 0:; } > } > > switch (i) // { dg-error "invalid entry to OpenACC structured block" } > { > - #pragma acc kernels > + #pragma acc kernels // { dg-warning "statement will never be executed" } > { case 0:; } > } > > switch (i) // { dg-error "invalid entry to OpenACC structured block" } > { > - #pragma acc data > + #pragma acc data // { dg-warning "statement will never be executed" } > { case 0:; } > } > } > diff --git gcc/testsuite/gcc.dg/Wjump-misses-init-1.c gcc/testsuite/gcc.dg/Wjump-misses-init-1.c > index 86117f1..71809be 100644 > --- gcc/testsuite/gcc.dg/Wjump-misses-init-1.c > +++ gcc/testsuite/gcc.dg/Wjump-misses-init-1.c > @@ -1,5 +1,5 @@ > /* { dg-do compile } */ > -/* { dg-options "-Wjump-misses-init" } */ > +/* { dg-options "-Wjump-misses-init -Wno-switch-unreachable" } */ > int > f1 (int a) > { > diff --git gcc/testsuite/gcc.dg/Wswitch-unreachable-1.c gcc/testsuite/gcc.dg/Wswitch-unreachable-1.c > index e69de29..ec620d3 100644 > --- gcc/testsuite/gcc.dg/Wswitch-unreachable-1.c > +++ gcc/testsuite/gcc.dg/Wswitch-unreachable-1.c > @@ -0,0 +1,135 @@ > +/* PR c/49859 */ > +/* { dg-do compile } */ > +/* { dg-options "-Wswitch-unreachable" } */ > + > +extern void foo (int); > +extern int j; > + > +void > +fn0 (int i) > +{ > + switch (i) > + { > + int k; > + case 1: > + k = 11; > + foo (k); > + } > + > + switch (i) > + j = 10; /* { dg-warning "statement will never be executed" } */ > + > + switch (i) > + ; > + > + switch (i) > + { > + int t = 10; /* { dg-warning "statement will never be executed" } */ > + default: > + foo (t); > + } > + > + switch (i) > + { > + j = 12; /* { dg-warning "statement will never be executed" } */ > + default: > + foo (j); > + } > + > + int o; > + switch (i) > + { > + o = 333; /* { dg-warning "statement will never be executed" } */ > + case 4: break; > + default: > + foo (o); > + } > + > + switch (i) > + switch (j) /* { dg-warning "statement will never be executed" } */ > + { > + o = 42; /* { dg-warning "statement will never be executed" } */ > + case 8:; > + } > + > + switch (i) > + { > + int l = 3; /* { dg-warning "statement will never be executed" } */ > + o = 5; > + j = 7; > + ++l; > + } > + > + switch (i) > + if (j != 3) /* { dg-warning "statement will never be executed" } */ > + foo (j); > + > + switch (i) > + while (1) > + foo (0); > + > + switch (i) > + while (i > 5) { } > + > + switch (i) > + goto X; /* { dg-warning "statement will never be executed" } */ > +X: > + > + switch (i) > + do > + foo (1); > + while (1); > + > + switch (i) > + for (;;) > + foo (-1); > + > + switch (i) > + default: > + j = 6; > + > + switch (i) > + default: > + j = sizeof (struct { int i; }); > + > + switch (i) > + { > + typedef int T; > + case 3: > + { > + T x = 5; > + foo (x); > + } > + } > + > + switch (i) > + { > + static int g; > + default: > + foo (g); > + } > + > + switch (i) > + { > +L: > + j = 16; > + default: > + if (j < 5) > + goto L; > + break; > + } > + > + switch (i) > + { > + int A[i]; /* { dg-warning "statement will never be executed" } */ > + default: /* { dg-error "switch jumps into scope" } */ > + break; > + } > + > + switch (i) > + { > + int A[3]; > + default: > + break; > + } > +} > diff --git gcc/testsuite/gcc.dg/c99-vla-jump-5.c gcc/testsuite/gcc.dg/c99-vla-jump-5.c > index fc5e04d..b5b85fd 100644 > --- gcc/testsuite/gcc.dg/c99-vla-jump-5.c > +++ gcc/testsuite/gcc.dg/c99-vla-jump-5.c > @@ -15,7 +15,7 @@ void > f (int a, int b) > { > switch (a) { > - int v[b]; > + int v[b]; /* { dg-warning "statement will never be executed" } */ > case 2: /* { dg-error "switch jumps into scope of identifier with variably modified type" } */ > default: /* { dg-error "switch jumps into scope of identifier with variably modified type" } */ > switch (a) > diff --git gcc/testsuite/gcc.dg/gomp/block-10.c gcc/testsuite/gcc.dg/gomp/block-10.c > index 69ae3c0..29c2d91 100644 > --- gcc/testsuite/gcc.dg/gomp/block-10.c > +++ gcc/testsuite/gcc.dg/gomp/block-10.c > @@ -5,28 +5,28 @@ void foo(int i) > int j; > switch (i) // { dg-error "invalid entry to OpenMP structured block" } > { > - #pragma omp parallel > + #pragma omp parallel // { dg-warning "statement will never be executed" } > { case 0:; } > } > switch (i) // { dg-error "invalid entry to OpenMP structured block" } > { > - #pragma omp for > + #pragma omp for // { dg-warning "statement will never be executed" } > for (j = 0; j < 10; ++ j) > { case 1:; } > } > switch (i) // { dg-error "invalid entry to OpenMP structured block" } > { > - #pragma omp critical > + #pragma omp critical // { dg-warning "statement will never be executed" } > { case 2:; } > } > switch (i) // { dg-error "invalid entry to OpenMP structured block" } > { > - #pragma omp master > + #pragma omp master // { dg-warning "statement will never be executed" } > { case 3:; } > } > switch (i) // { dg-error "invalid entry to OpenMP structured block" } > { > - #pragma omp sections > + #pragma omp sections // { dg-warning "statement will never be executed" } > { case 4:; > #pragma omp section > { case 5:; } > @@ -34,7 +34,7 @@ void foo(int i) > } > switch (i) // { dg-error "invalid entry to OpenMP structured block" } > { > - #pragma omp ordered > + #pragma omp ordered // { dg-warning "statement will never be executed" } > { default:; } > } > } > diff --git gcc/testsuite/gcc.dg/gomp/block-9.c gcc/testsuite/gcc.dg/gomp/block-9.c > index 2fae3de..202599f 100644 > --- gcc/testsuite/gcc.dg/gomp/block-9.c > +++ gcc/testsuite/gcc.dg/gomp/block-9.c > @@ -5,7 +5,7 @@ void foo(int i) > int j; > switch (i) // { dg-error "invalid entry to OpenMP structured block" } > { > - #pragma omp parallel > + #pragma omp parallel // { dg-warning "statement will never be executed" } > { case 0:; } > #pragma omp for > for (j = 0; j < 10; ++ j) > diff --git gcc/testsuite/gcc.dg/gomp/target-1.c gcc/testsuite/gcc.dg/gomp/target-1.c > index aaa6a14..6bc5eb9 100644 > --- gcc/testsuite/gcc.dg/gomp/target-1.c > +++ gcc/testsuite/gcc.dg/gomp/target-1.c > @@ -23,7 +23,7 @@ foo (int x) > > switch (x) // { dg-error "invalid entry to OpenMP structured block" } > { > - #pragma omp target > + #pragma omp target // { dg-warning "statement will never be executed" } > { case 0:; } > } > } > diff --git gcc/testsuite/gcc.dg/gomp/target-2.c gcc/testsuite/gcc.dg/gomp/target-2.c > index 3a7afc4..c5c38d8 100644 > --- gcc/testsuite/gcc.dg/gomp/target-2.c > +++ gcc/testsuite/gcc.dg/gomp/target-2.c > @@ -23,7 +23,7 @@ foo (int x, int y) > > switch (x) // { dg-error "invalid entry to OpenMP structured block" } > { > - #pragma omp target data map(tofrom: y) > + #pragma omp target data map(tofrom: y) // { dg-warning "statement will never be executed" } > { case 0:; } > } > } > diff --git gcc/testsuite/gcc.dg/gomp/taskgroup-1.c gcc/testsuite/gcc.dg/gomp/taskgroup-1.c > index 1997e0c..f39b7ef 100644 > --- gcc/testsuite/gcc.dg/gomp/taskgroup-1.c > +++ gcc/testsuite/gcc.dg/gomp/taskgroup-1.c > @@ -23,7 +23,7 @@ foo (int x) > > switch (x) // { dg-error "invalid entry to OpenMP structured block" } > { > - #pragma omp taskgroup > + #pragma omp taskgroup // { dg-warning "statement will never be executed" } > { case 0:; } > } > } > diff --git gcc/testsuite/gcc.dg/gomp/teams-1.c gcc/testsuite/gcc.dg/gomp/teams-1.c > index ad5b100..db7f50b 100644 > --- gcc/testsuite/gcc.dg/gomp/teams-1.c > +++ gcc/testsuite/gcc.dg/gomp/teams-1.c > @@ -23,7 +23,7 @@ foo (int x) > > switch (x) // { dg-error "invalid entry to OpenMP structured block" } > { > - #pragma omp target teams > + #pragma omp target teams // { dg-warning "statement will never be executed" } > { case 0:; } > } > } > @@ -54,7 +54,7 @@ bar (int x) > > switch (x) // { dg-error "invalid entry to OpenMP structured block" } > { > - #pragma omp target > + #pragma omp target // { dg-warning "statement will never be executed" } > #pragma omp teams > { case 0:; } > } > diff --git gcc/testsuite/gcc.dg/nested-func-1.c gcc/testsuite/gcc.dg/nested-func-1.c > index cb26e89..2052a6f 100644 > --- gcc/testsuite/gcc.dg/nested-func-1.c > +++ gcc/testsuite/gcc.dg/nested-func-1.c > @@ -1,7 +1,7 @@ > /* Test for proper errors for break and continue in nested functions. */ > /* Origin: Joseph Myers <jsm@polyomino.org.uk> */ > /* { dg-do compile } */ > -/* { dg-options "" } */ > +/* { dg-options "-Wno-switch-unreachable" } */ > > void > foo (int a) > diff --git gcc/testsuite/gcc.dg/pr67784-4.c gcc/testsuite/gcc.dg/pr67784-4.c > index 81a43fd..5462080 100644 > --- gcc/testsuite/gcc.dg/pr67784-4.c > +++ gcc/testsuite/gcc.dg/pr67784-4.c > @@ -1,6 +1,6 @@ > /* PR c/67784 */ > /* { dg-do compile } */ > -/* { dg-options "" } */ > +/* { dg-options "-Wno-switch-unreachable" } */ > > typedef int T; > > diff --git gcc/testsuite/gcc.dg/switch-warn-1.c gcc/testsuite/gcc.dg/switch-warn-1.c > index 04ca4e3..58fbd7d 100644 > --- gcc/testsuite/gcc.dg/switch-warn-1.c > +++ gcc/testsuite/gcc.dg/switch-warn-1.c > @@ -11,7 +11,7 @@ foo1 (unsigned char i) > { > switch (i) > { > - case -1: /* { dg-warning "case label value is less than minimum value for type" } */ > + case -1: /* { dg-warning "case label value is less than minimum value for type|statement will never be executed" } */ > return 1; > case 256: /* { dg-warning "case label value exceeds maximum value for type" } */ > return 2; > > Marek Marek
Why implement this in the front end rather than at the gimple level? Jason On Tue, May 10, 2016 at 2:19 PM, Marek Polacek <polacek@redhat.com> wrote: > Over the years, we got several PRs that suggested to add a warning that would > warn about unreachable statements between `switch (cond)' and the first case. > In some cases our -Wuninitialized warning can detect such a case, but mostly > not. This patch is an attempt to add a proper warning about this peculiar > case. I chose to not warn about declarations between switch and the first > case, because we use that in the codebase and I think this kind of use is > fine. As it's usually the case, some obscure cases cropped up during testing, > this time those were Duff's devices, so I had to go the extra mile to handle > them specially. > > This is a C FE part only; I'd like to hear some feedback first before I plunge > into the C++ FE. > > Bootstrapped/regtested on x86_64-linux, ok for trunk? > > 2016-05-10 Marek Polacek <polacek@redhat.com> > > PR c/49859 > * c.opt (Wswitch-unreachable): New option. > > * c-parser.c: Include tree-iterator.h. > (c_parser_switch_statement): Implement -Wswitch-unreachable warning. > > * doc/invoke.texi: Document -Wswitch-unreachable. > > * gcc.dg/Wjump-misses-init-1.c: Use -Wno-switch-unreachable. > * gcc.dg/nested-func-1.c: Likewise. > * gcc.dg/pr67784-4.c: Likewise. > * gcc.dg/Wswitch-unreachable-1.c: New test. > * gcc.dg/c99-vla-jump-5.c (f): Add dg-warning. > * gcc.dg/switch-warn-1.c (foo1): Likewise. > * c-c++-common/goacc/sb-2.c: Likewise. > * gcc.dg/gomp/block-10.c: Likewise. > * gcc.dg/gomp/block-9.c: Likewise. > * gcc.dg/gomp/target-1.c: Likewise. > * gcc.dg/gomp/target-2.c: Likewise. > * gcc.dg/gomp/taskgroup-1.c: Likewise. > * gcc.dg/gomp/teams-1.c: Likewise. > > diff --git gcc/c-family/c.opt gcc/c-family/c.opt > index bdc6ee0..8b6fdbb 100644 > --- gcc/c-family/c.opt > +++ gcc/c-family/c.opt > @@ -634,6 +634,11 @@ Wswitch-bool > C ObjC C++ ObjC++ Var(warn_switch_bool) Warning Init(1) > Warn about switches with boolean controlling expression. > > +Wswitch-unreachable > +C ObjC C++ ObjC++ Var(warn_switch_unreachable) Warning Init(1) > +Warn about statements between switch's controlling expression and the first > +case. > + > Wtemplates > C++ ObjC++ Var(warn_templates) Warning > Warn on primary template declaration. > diff --git gcc/c/c-parser.c gcc/c/c-parser.c > index 6523c08..bdf8e8e 100644 > --- gcc/c/c-parser.c > +++ gcc/c/c-parser.c > @@ -58,6 +58,7 @@ along with GCC; see the file COPYING3. If not see > #include "c-family/c-indentation.h" > #include "gimple-expr.h" > #include "context.h" > +#include "tree-iterator.h" > > /* We need to walk over decls with incomplete struct/union/enum types > after parsing the whole translation unit. > @@ -5605,7 +5606,30 @@ c_parser_switch_statement (c_parser *parser, bool *if_p) > c_start_case (switch_loc, switch_cond_loc, expr, explicit_cast_p); > save_break = c_break_label; > c_break_label = NULL_TREE; > + location_t first_loc = (c_parser_next_token_is (parser, CPP_OPEN_BRACE) > + ? c_parser_peek_2nd_token (parser)->location > + : c_parser_peek_token (parser)->location); > body = c_parser_c99_block_statement (parser, if_p); > + tree first = expr_first (TREE_CODE (body) == BIND_EXPR > + ? BIND_EXPR_BODY (body) : body); > + /* Statements between `switch' and the first case are never executed. */ > + if (warn_switch_unreachable > + && first != NULL_TREE > + && TREE_CODE (first) != CASE_LABEL_EXPR > + && TREE_CODE (first) != LABEL_EXPR) > + { > + if (TREE_CODE (first) == DECL_EXPR > + && DECL_INITIAL (DECL_EXPR_DECL (first)) == NULL_TREE) > + /* Don't warn for a declaration, but warn for an initialization. */; > + else if (TREE_CODE (first) == GOTO_EXPR > + && TREE_CODE (GOTO_DESTINATION (first)) == LABEL_DECL > + && DECL_ARTIFICIAL (GOTO_DESTINATION (first))) > + /* Don't warn for compiler-generated gotos. These occur in Duff's > + devices, for example. */; > + else > + warning_at (first_loc, OPT_Wswitch_unreachable, > + "statement will never be executed"); > + } > c_finish_case (body, ce.original_type); > if (c_break_label) > { > diff --git gcc/doc/invoke.texi gcc/doc/invoke.texi > index a54a0af..8f9c186 100644 > --- gcc/doc/invoke.texi > +++ gcc/doc/invoke.texi > @@ -297,7 +297,8 @@ Objective-C and Objective-C++ Dialects}. > -Wsuggest-attribute=@r{[}pure@r{|}const@r{|}noreturn@r{|}format@r{]} @gol > -Wsuggest-final-types @gol -Wsuggest-final-methods -Wsuggest-override @gol > -Wmissing-format-attribute -Wsubobject-linkage @gol > --Wswitch -Wswitch-default -Wswitch-enum -Wswitch-bool -Wsync-nand @gol > +-Wswitch -Wswitch-default -Wswitch-enum -Wswitch-bool @gol > +-Wswitch-unreachable -Wsync-nand @gol > -Wsystem-headers -Wtautological-compare -Wtrampolines -Wtrigraphs @gol > -Wtype-limits -Wundef @gol > -Wuninitialized -Wunknown-pragmas -Wunsafe-loop-optimizations @gol > @@ -4135,6 +4136,39 @@ switch ((int) (a == 4)) > @end smallexample > This warning is enabled by default for C and C++ programs. > > +@item -Wswitch-unreachable > +@opindex Wswitch-unreachable > +@opindex Wno-switch-unreachable > +Warn whenever a @code{switch} statement contains statements between the > +controlling expression and the first case label, which will never be > +executed. For example: > +@smallexample > +@group > +switch (cond) > + @{ > + i = 15; > + @dots{} > + case 5: > + @dots{} > + @} > +@end group > +@end smallexample > +@option{-Wswitch-unreachable} will not warn if the statement between the > +controlling expression and the first case label is just a declaration: > +@smallexample > +@group > +switch (cond) > + @{ > + int i; > + @dots{} > + case 5: > + i = 5; > + @dots{} > + @} > +@end group > +@end smallexample > +This warning is enabled by default for C and C++ programs. > + > @item -Wsync-nand @r{(C and C++ only)} > @opindex Wsync-nand > @opindex Wno-sync-nand > diff --git gcc/testsuite/c-c++-common/goacc/sb-2.c gcc/testsuite/c-c++-common/goacc/sb-2.c > index a6760ec..e986af3 100644 > --- gcc/testsuite/c-c++-common/goacc/sb-2.c > +++ gcc/testsuite/c-c++-common/goacc/sb-2.c > @@ -4,19 +4,19 @@ void foo(int i) > { > switch (i) // { dg-error "invalid entry to OpenACC structured block" } > { > - #pragma acc parallel > + #pragma acc parallel // { dg-warning "statement will never be executed" } > { case 0:; } > } > > switch (i) // { dg-error "invalid entry to OpenACC structured block" } > { > - #pragma acc kernels > + #pragma acc kernels // { dg-warning "statement will never be executed" } > { case 0:; } > } > > switch (i) // { dg-error "invalid entry to OpenACC structured block" } > { > - #pragma acc data > + #pragma acc data // { dg-warning "statement will never be executed" } > { case 0:; } > } > } > diff --git gcc/testsuite/gcc.dg/Wjump-misses-init-1.c gcc/testsuite/gcc.dg/Wjump-misses-init-1.c > index 86117f1..71809be 100644 > --- gcc/testsuite/gcc.dg/Wjump-misses-init-1.c > +++ gcc/testsuite/gcc.dg/Wjump-misses-init-1.c > @@ -1,5 +1,5 @@ > /* { dg-do compile } */ > -/* { dg-options "-Wjump-misses-init" } */ > +/* { dg-options "-Wjump-misses-init -Wno-switch-unreachable" } */ > int > f1 (int a) > { > diff --git gcc/testsuite/gcc.dg/Wswitch-unreachable-1.c gcc/testsuite/gcc.dg/Wswitch-unreachable-1.c > index e69de29..ec620d3 100644 > --- gcc/testsuite/gcc.dg/Wswitch-unreachable-1.c > +++ gcc/testsuite/gcc.dg/Wswitch-unreachable-1.c > @@ -0,0 +1,135 @@ > +/* PR c/49859 */ > +/* { dg-do compile } */ > +/* { dg-options "-Wswitch-unreachable" } */ > + > +extern void foo (int); > +extern int j; > + > +void > +fn0 (int i) > +{ > + switch (i) > + { > + int k; > + case 1: > + k = 11; > + foo (k); > + } > + > + switch (i) > + j = 10; /* { dg-warning "statement will never be executed" } */ > + > + switch (i) > + ; > + > + switch (i) > + { > + int t = 10; /* { dg-warning "statement will never be executed" } */ > + default: > + foo (t); > + } > + > + switch (i) > + { > + j = 12; /* { dg-warning "statement will never be executed" } */ > + default: > + foo (j); > + } > + > + int o; > + switch (i) > + { > + o = 333; /* { dg-warning "statement will never be executed" } */ > + case 4: break; > + default: > + foo (o); > + } > + > + switch (i) > + switch (j) /* { dg-warning "statement will never be executed" } */ > + { > + o = 42; /* { dg-warning "statement will never be executed" } */ > + case 8:; > + } > + > + switch (i) > + { > + int l = 3; /* { dg-warning "statement will never be executed" } */ > + o = 5; > + j = 7; > + ++l; > + } > + > + switch (i) > + if (j != 3) /* { dg-warning "statement will never be executed" } */ > + foo (j); > + > + switch (i) > + while (1) > + foo (0); > + > + switch (i) > + while (i > 5) { } > + > + switch (i) > + goto X; /* { dg-warning "statement will never be executed" } */ > +X: > + > + switch (i) > + do > + foo (1); > + while (1); > + > + switch (i) > + for (;;) > + foo (-1); > + > + switch (i) > + default: > + j = 6; > + > + switch (i) > + default: > + j = sizeof (struct { int i; }); > + > + switch (i) > + { > + typedef int T; > + case 3: > + { > + T x = 5; > + foo (x); > + } > + } > + > + switch (i) > + { > + static int g; > + default: > + foo (g); > + } > + > + switch (i) > + { > +L: > + j = 16; > + default: > + if (j < 5) > + goto L; > + break; > + } > + > + switch (i) > + { > + int A[i]; /* { dg-warning "statement will never be executed" } */ > + default: /* { dg-error "switch jumps into scope" } */ > + break; > + } > + > + switch (i) > + { > + int A[3]; > + default: > + break; > + } > +} > diff --git gcc/testsuite/gcc.dg/c99-vla-jump-5.c gcc/testsuite/gcc.dg/c99-vla-jump-5.c > index fc5e04d..b5b85fd 100644 > --- gcc/testsuite/gcc.dg/c99-vla-jump-5.c > +++ gcc/testsuite/gcc.dg/c99-vla-jump-5.c > @@ -15,7 +15,7 @@ void > f (int a, int b) > { > switch (a) { > - int v[b]; > + int v[b]; /* { dg-warning "statement will never be executed" } */ > case 2: /* { dg-error "switch jumps into scope of identifier with variably modified type" } */ > default: /* { dg-error "switch jumps into scope of identifier with variably modified type" } */ > switch (a) > diff --git gcc/testsuite/gcc.dg/gomp/block-10.c gcc/testsuite/gcc.dg/gomp/block-10.c > index 69ae3c0..29c2d91 100644 > --- gcc/testsuite/gcc.dg/gomp/block-10.c > +++ gcc/testsuite/gcc.dg/gomp/block-10.c > @@ -5,28 +5,28 @@ void foo(int i) > int j; > switch (i) // { dg-error "invalid entry to OpenMP structured block" } > { > - #pragma omp parallel > + #pragma omp parallel // { dg-warning "statement will never be executed" } > { case 0:; } > } > switch (i) // { dg-error "invalid entry to OpenMP structured block" } > { > - #pragma omp for > + #pragma omp for // { dg-warning "statement will never be executed" } > for (j = 0; j < 10; ++ j) > { case 1:; } > } > switch (i) // { dg-error "invalid entry to OpenMP structured block" } > { > - #pragma omp critical > + #pragma omp critical // { dg-warning "statement will never be executed" } > { case 2:; } > } > switch (i) // { dg-error "invalid entry to OpenMP structured block" } > { > - #pragma omp master > + #pragma omp master // { dg-warning "statement will never be executed" } > { case 3:; } > } > switch (i) // { dg-error "invalid entry to OpenMP structured block" } > { > - #pragma omp sections > + #pragma omp sections // { dg-warning "statement will never be executed" } > { case 4:; > #pragma omp section > { case 5:; } > @@ -34,7 +34,7 @@ void foo(int i) > } > switch (i) // { dg-error "invalid entry to OpenMP structured block" } > { > - #pragma omp ordered > + #pragma omp ordered // { dg-warning "statement will never be executed" } > { default:; } > } > } > diff --git gcc/testsuite/gcc.dg/gomp/block-9.c gcc/testsuite/gcc.dg/gomp/block-9.c > index 2fae3de..202599f 100644 > --- gcc/testsuite/gcc.dg/gomp/block-9.c > +++ gcc/testsuite/gcc.dg/gomp/block-9.c > @@ -5,7 +5,7 @@ void foo(int i) > int j; > switch (i) // { dg-error "invalid entry to OpenMP structured block" } > { > - #pragma omp parallel > + #pragma omp parallel // { dg-warning "statement will never be executed" } > { case 0:; } > #pragma omp for > for (j = 0; j < 10; ++ j) > diff --git gcc/testsuite/gcc.dg/gomp/target-1.c gcc/testsuite/gcc.dg/gomp/target-1.c > index aaa6a14..6bc5eb9 100644 > --- gcc/testsuite/gcc.dg/gomp/target-1.c > +++ gcc/testsuite/gcc.dg/gomp/target-1.c > @@ -23,7 +23,7 @@ foo (int x) > > switch (x) // { dg-error "invalid entry to OpenMP structured block" } > { > - #pragma omp target > + #pragma omp target // { dg-warning "statement will never be executed" } > { case 0:; } > } > } > diff --git gcc/testsuite/gcc.dg/gomp/target-2.c gcc/testsuite/gcc.dg/gomp/target-2.c > index 3a7afc4..c5c38d8 100644 > --- gcc/testsuite/gcc.dg/gomp/target-2.c > +++ gcc/testsuite/gcc.dg/gomp/target-2.c > @@ -23,7 +23,7 @@ foo (int x, int y) > > switch (x) // { dg-error "invalid entry to OpenMP structured block" } > { > - #pragma omp target data map(tofrom: y) > + #pragma omp target data map(tofrom: y) // { dg-warning "statement will never be executed" } > { case 0:; } > } > } > diff --git gcc/testsuite/gcc.dg/gomp/taskgroup-1.c gcc/testsuite/gcc.dg/gomp/taskgroup-1.c > index 1997e0c..f39b7ef 100644 > --- gcc/testsuite/gcc.dg/gomp/taskgroup-1.c > +++ gcc/testsuite/gcc.dg/gomp/taskgroup-1.c > @@ -23,7 +23,7 @@ foo (int x) > > switch (x) // { dg-error "invalid entry to OpenMP structured block" } > { > - #pragma omp taskgroup > + #pragma omp taskgroup // { dg-warning "statement will never be executed" } > { case 0:; } > } > } > diff --git gcc/testsuite/gcc.dg/gomp/teams-1.c gcc/testsuite/gcc.dg/gomp/teams-1.c > index ad5b100..db7f50b 100644 > --- gcc/testsuite/gcc.dg/gomp/teams-1.c > +++ gcc/testsuite/gcc.dg/gomp/teams-1.c > @@ -23,7 +23,7 @@ foo (int x) > > switch (x) // { dg-error "invalid entry to OpenMP structured block" } > { > - #pragma omp target teams > + #pragma omp target teams // { dg-warning "statement will never be executed" } > { case 0:; } > } > } > @@ -54,7 +54,7 @@ bar (int x) > > switch (x) // { dg-error "invalid entry to OpenMP structured block" } > { > - #pragma omp target > + #pragma omp target // { dg-warning "statement will never be executed" } > #pragma omp teams > { case 0:; } > } > diff --git gcc/testsuite/gcc.dg/nested-func-1.c gcc/testsuite/gcc.dg/nested-func-1.c > index cb26e89..2052a6f 100644 > --- gcc/testsuite/gcc.dg/nested-func-1.c > +++ gcc/testsuite/gcc.dg/nested-func-1.c > @@ -1,7 +1,7 @@ > /* Test for proper errors for break and continue in nested functions. */ > /* Origin: Joseph Myers <jsm@polyomino.org.uk> */ > /* { dg-do compile } */ > -/* { dg-options "" } */ > +/* { dg-options "-Wno-switch-unreachable" } */ > > void > foo (int a) > diff --git gcc/testsuite/gcc.dg/pr67784-4.c gcc/testsuite/gcc.dg/pr67784-4.c > index 81a43fd..5462080 100644 > --- gcc/testsuite/gcc.dg/pr67784-4.c > +++ gcc/testsuite/gcc.dg/pr67784-4.c > @@ -1,6 +1,6 @@ > /* PR c/67784 */ > /* { dg-do compile } */ > -/* { dg-options "" } */ > +/* { dg-options "-Wno-switch-unreachable" } */ > > typedef int T; > > diff --git gcc/testsuite/gcc.dg/switch-warn-1.c gcc/testsuite/gcc.dg/switch-warn-1.c > index 04ca4e3..58fbd7d 100644 > --- gcc/testsuite/gcc.dg/switch-warn-1.c > +++ gcc/testsuite/gcc.dg/switch-warn-1.c > @@ -11,7 +11,7 @@ foo1 (unsigned char i) > { > switch (i) > { > - case -1: /* { dg-warning "case label value is less than minimum value for type" } */ > + case -1: /* { dg-warning "case label value is less than minimum value for type|statement will never be executed" } */ > return 1; > case 256: /* { dg-warning "case label value exceeds maximum value for type" } */ > return 2; > > Marek
diff --git gcc/c-family/c.opt gcc/c-family/c.opt index bdc6ee0..8b6fdbb 100644 --- gcc/c-family/c.opt +++ gcc/c-family/c.opt @@ -634,6 +634,11 @@ Wswitch-bool C ObjC C++ ObjC++ Var(warn_switch_bool) Warning Init(1) Warn about switches with boolean controlling expression. +Wswitch-unreachable +C ObjC C++ ObjC++ Var(warn_switch_unreachable) Warning Init(1) +Warn about statements between switch's controlling expression and the first +case. + Wtemplates C++ ObjC++ Var(warn_templates) Warning Warn on primary template declaration. diff --git gcc/c/c-parser.c gcc/c/c-parser.c index 6523c08..bdf8e8e 100644 --- gcc/c/c-parser.c +++ gcc/c/c-parser.c @@ -58,6 +58,7 @@ along with GCC; see the file COPYING3. If not see #include "c-family/c-indentation.h" #include "gimple-expr.h" #include "context.h" +#include "tree-iterator.h" /* We need to walk over decls with incomplete struct/union/enum types after parsing the whole translation unit. @@ -5605,7 +5606,30 @@ c_parser_switch_statement (c_parser *parser, bool *if_p) c_start_case (switch_loc, switch_cond_loc, expr, explicit_cast_p); save_break = c_break_label; c_break_label = NULL_TREE; + location_t first_loc = (c_parser_next_token_is (parser, CPP_OPEN_BRACE) + ? c_parser_peek_2nd_token (parser)->location + : c_parser_peek_token (parser)->location); body = c_parser_c99_block_statement (parser, if_p); + tree first = expr_first (TREE_CODE (body) == BIND_EXPR + ? BIND_EXPR_BODY (body) : body); + /* Statements between `switch' and the first case are never executed. */ + if (warn_switch_unreachable + && first != NULL_TREE + && TREE_CODE (first) != CASE_LABEL_EXPR + && TREE_CODE (first) != LABEL_EXPR) + { + if (TREE_CODE (first) == DECL_EXPR + && DECL_INITIAL (DECL_EXPR_DECL (first)) == NULL_TREE) + /* Don't warn for a declaration, but warn for an initialization. */; + else if (TREE_CODE (first) == GOTO_EXPR + && TREE_CODE (GOTO_DESTINATION (first)) == LABEL_DECL + && DECL_ARTIFICIAL (GOTO_DESTINATION (first))) + /* Don't warn for compiler-generated gotos. These occur in Duff's + devices, for example. */; + else + warning_at (first_loc, OPT_Wswitch_unreachable, + "statement will never be executed"); + } c_finish_case (body, ce.original_type); if (c_break_label) { diff --git gcc/doc/invoke.texi gcc/doc/invoke.texi index a54a0af..8f9c186 100644 --- gcc/doc/invoke.texi +++ gcc/doc/invoke.texi @@ -297,7 +297,8 @@ Objective-C and Objective-C++ Dialects}. -Wsuggest-attribute=@r{[}pure@r{|}const@r{|}noreturn@r{|}format@r{]} @gol -Wsuggest-final-types @gol -Wsuggest-final-methods -Wsuggest-override @gol -Wmissing-format-attribute -Wsubobject-linkage @gol --Wswitch -Wswitch-default -Wswitch-enum -Wswitch-bool -Wsync-nand @gol +-Wswitch -Wswitch-default -Wswitch-enum -Wswitch-bool @gol +-Wswitch-unreachable -Wsync-nand @gol -Wsystem-headers -Wtautological-compare -Wtrampolines -Wtrigraphs @gol -Wtype-limits -Wundef @gol -Wuninitialized -Wunknown-pragmas -Wunsafe-loop-optimizations @gol @@ -4135,6 +4136,39 @@ switch ((int) (a == 4)) @end smallexample This warning is enabled by default for C and C++ programs. +@item -Wswitch-unreachable +@opindex Wswitch-unreachable +@opindex Wno-switch-unreachable +Warn whenever a @code{switch} statement contains statements between the +controlling expression and the first case label, which will never be +executed. For example: +@smallexample +@group +switch (cond) + @{ + i = 15; + @dots{} + case 5: + @dots{} + @} +@end group +@end smallexample +@option{-Wswitch-unreachable} will not warn if the statement between the +controlling expression and the first case label is just a declaration: +@smallexample +@group +switch (cond) + @{ + int i; + @dots{} + case 5: + i = 5; + @dots{} + @} +@end group +@end smallexample +This warning is enabled by default for C and C++ programs. + @item -Wsync-nand @r{(C and C++ only)} @opindex Wsync-nand @opindex Wno-sync-nand diff --git gcc/testsuite/c-c++-common/goacc/sb-2.c gcc/testsuite/c-c++-common/goacc/sb-2.c index a6760ec..e986af3 100644 --- gcc/testsuite/c-c++-common/goacc/sb-2.c +++ gcc/testsuite/c-c++-common/goacc/sb-2.c @@ -4,19 +4,19 @@ void foo(int i) { switch (i) // { dg-error "invalid entry to OpenACC structured block" } { - #pragma acc parallel + #pragma acc parallel // { dg-warning "statement will never be executed" } { case 0:; } } switch (i) // { dg-error "invalid entry to OpenACC structured block" } { - #pragma acc kernels + #pragma acc kernels // { dg-warning "statement will never be executed" } { case 0:; } } switch (i) // { dg-error "invalid entry to OpenACC structured block" } { - #pragma acc data + #pragma acc data // { dg-warning "statement will never be executed" } { case 0:; } } } diff --git gcc/testsuite/gcc.dg/Wjump-misses-init-1.c gcc/testsuite/gcc.dg/Wjump-misses-init-1.c index 86117f1..71809be 100644 --- gcc/testsuite/gcc.dg/Wjump-misses-init-1.c +++ gcc/testsuite/gcc.dg/Wjump-misses-init-1.c @@ -1,5 +1,5 @@ /* { dg-do compile } */ -/* { dg-options "-Wjump-misses-init" } */ +/* { dg-options "-Wjump-misses-init -Wno-switch-unreachable" } */ int f1 (int a) { diff --git gcc/testsuite/gcc.dg/Wswitch-unreachable-1.c gcc/testsuite/gcc.dg/Wswitch-unreachable-1.c index e69de29..ec620d3 100644 --- gcc/testsuite/gcc.dg/Wswitch-unreachable-1.c +++ gcc/testsuite/gcc.dg/Wswitch-unreachable-1.c @@ -0,0 +1,135 @@ +/* PR c/49859 */ +/* { dg-do compile } */ +/* { dg-options "-Wswitch-unreachable" } */ + +extern void foo (int); +extern int j; + +void +fn0 (int i) +{ + switch (i) + { + int k; + case 1: + k = 11; + foo (k); + } + + switch (i) + j = 10; /* { dg-warning "statement will never be executed" } */ + + switch (i) + ; + + switch (i) + { + int t = 10; /* { dg-warning "statement will never be executed" } */ + default: + foo (t); + } + + switch (i) + { + j = 12; /* { dg-warning "statement will never be executed" } */ + default: + foo (j); + } + + int o; + switch (i) + { + o = 333; /* { dg-warning "statement will never be executed" } */ + case 4: break; + default: + foo (o); + } + + switch (i) + switch (j) /* { dg-warning "statement will never be executed" } */ + { + o = 42; /* { dg-warning "statement will never be executed" } */ + case 8:; + } + + switch (i) + { + int l = 3; /* { dg-warning "statement will never be executed" } */ + o = 5; + j = 7; + ++l; + } + + switch (i) + if (j != 3) /* { dg-warning "statement will never be executed" } */ + foo (j); + + switch (i) + while (1) + foo (0); + + switch (i) + while (i > 5) { } + + switch (i) + goto X; /* { dg-warning "statement will never be executed" } */ +X: + + switch (i) + do + foo (1); + while (1); + + switch (i) + for (;;) + foo (-1); + + switch (i) + default: + j = 6; + + switch (i) + default: + j = sizeof (struct { int i; }); + + switch (i) + { + typedef int T; + case 3: + { + T x = 5; + foo (x); + } + } + + switch (i) + { + static int g; + default: + foo (g); + } + + switch (i) + { +L: + j = 16; + default: + if (j < 5) + goto L; + break; + } + + switch (i) + { + int A[i]; /* { dg-warning "statement will never be executed" } */ + default: /* { dg-error "switch jumps into scope" } */ + break; + } + + switch (i) + { + int A[3]; + default: + break; + } +} diff --git gcc/testsuite/gcc.dg/c99-vla-jump-5.c gcc/testsuite/gcc.dg/c99-vla-jump-5.c index fc5e04d..b5b85fd 100644 --- gcc/testsuite/gcc.dg/c99-vla-jump-5.c +++ gcc/testsuite/gcc.dg/c99-vla-jump-5.c @@ -15,7 +15,7 @@ void f (int a, int b) { switch (a) { - int v[b]; + int v[b]; /* { dg-warning "statement will never be executed" } */ case 2: /* { dg-error "switch jumps into scope of identifier with variably modified type" } */ default: /* { dg-error "switch jumps into scope of identifier with variably modified type" } */ switch (a) diff --git gcc/testsuite/gcc.dg/gomp/block-10.c gcc/testsuite/gcc.dg/gomp/block-10.c index 69ae3c0..29c2d91 100644 --- gcc/testsuite/gcc.dg/gomp/block-10.c +++ gcc/testsuite/gcc.dg/gomp/block-10.c @@ -5,28 +5,28 @@ void foo(int i) int j; switch (i) // { dg-error "invalid entry to OpenMP structured block" } { - #pragma omp parallel + #pragma omp parallel // { dg-warning "statement will never be executed" } { case 0:; } } switch (i) // { dg-error "invalid entry to OpenMP structured block" } { - #pragma omp for + #pragma omp for // { dg-warning "statement will never be executed" } for (j = 0; j < 10; ++ j) { case 1:; } } switch (i) // { dg-error "invalid entry to OpenMP structured block" } { - #pragma omp critical + #pragma omp critical // { dg-warning "statement will never be executed" } { case 2:; } } switch (i) // { dg-error "invalid entry to OpenMP structured block" } { - #pragma omp master + #pragma omp master // { dg-warning "statement will never be executed" } { case 3:; } } switch (i) // { dg-error "invalid entry to OpenMP structured block" } { - #pragma omp sections + #pragma omp sections // { dg-warning "statement will never be executed" } { case 4:; #pragma omp section { case 5:; } @@ -34,7 +34,7 @@ void foo(int i) } switch (i) // { dg-error "invalid entry to OpenMP structured block" } { - #pragma omp ordered + #pragma omp ordered // { dg-warning "statement will never be executed" } { default:; } } } diff --git gcc/testsuite/gcc.dg/gomp/block-9.c gcc/testsuite/gcc.dg/gomp/block-9.c index 2fae3de..202599f 100644 --- gcc/testsuite/gcc.dg/gomp/block-9.c +++ gcc/testsuite/gcc.dg/gomp/block-9.c @@ -5,7 +5,7 @@ void foo(int i) int j; switch (i) // { dg-error "invalid entry to OpenMP structured block" } { - #pragma omp parallel + #pragma omp parallel // { dg-warning "statement will never be executed" } { case 0:; } #pragma omp for for (j = 0; j < 10; ++ j) diff --git gcc/testsuite/gcc.dg/gomp/target-1.c gcc/testsuite/gcc.dg/gomp/target-1.c index aaa6a14..6bc5eb9 100644 --- gcc/testsuite/gcc.dg/gomp/target-1.c +++ gcc/testsuite/gcc.dg/gomp/target-1.c @@ -23,7 +23,7 @@ foo (int x) switch (x) // { dg-error "invalid entry to OpenMP structured block" } { - #pragma omp target + #pragma omp target // { dg-warning "statement will never be executed" } { case 0:; } } } diff --git gcc/testsuite/gcc.dg/gomp/target-2.c gcc/testsuite/gcc.dg/gomp/target-2.c index 3a7afc4..c5c38d8 100644 --- gcc/testsuite/gcc.dg/gomp/target-2.c +++ gcc/testsuite/gcc.dg/gomp/target-2.c @@ -23,7 +23,7 @@ foo (int x, int y) switch (x) // { dg-error "invalid entry to OpenMP structured block" } { - #pragma omp target data map(tofrom: y) + #pragma omp target data map(tofrom: y) // { dg-warning "statement will never be executed" } { case 0:; } } } diff --git gcc/testsuite/gcc.dg/gomp/taskgroup-1.c gcc/testsuite/gcc.dg/gomp/taskgroup-1.c index 1997e0c..f39b7ef 100644 --- gcc/testsuite/gcc.dg/gomp/taskgroup-1.c +++ gcc/testsuite/gcc.dg/gomp/taskgroup-1.c @@ -23,7 +23,7 @@ foo (int x) switch (x) // { dg-error "invalid entry to OpenMP structured block" } { - #pragma omp taskgroup + #pragma omp taskgroup // { dg-warning "statement will never be executed" } { case 0:; } } } diff --git gcc/testsuite/gcc.dg/gomp/teams-1.c gcc/testsuite/gcc.dg/gomp/teams-1.c index ad5b100..db7f50b 100644 --- gcc/testsuite/gcc.dg/gomp/teams-1.c +++ gcc/testsuite/gcc.dg/gomp/teams-1.c @@ -23,7 +23,7 @@ foo (int x) switch (x) // { dg-error "invalid entry to OpenMP structured block" } { - #pragma omp target teams + #pragma omp target teams // { dg-warning "statement will never be executed" } { case 0:; } } } @@ -54,7 +54,7 @@ bar (int x) switch (x) // { dg-error "invalid entry to OpenMP structured block" } { - #pragma omp target + #pragma omp target // { dg-warning "statement will never be executed" } #pragma omp teams { case 0:; } } diff --git gcc/testsuite/gcc.dg/nested-func-1.c gcc/testsuite/gcc.dg/nested-func-1.c index cb26e89..2052a6f 100644 --- gcc/testsuite/gcc.dg/nested-func-1.c +++ gcc/testsuite/gcc.dg/nested-func-1.c @@ -1,7 +1,7 @@ /* Test for proper errors for break and continue in nested functions. */ /* Origin: Joseph Myers <jsm@polyomino.org.uk> */ /* { dg-do compile } */ -/* { dg-options "" } */ +/* { dg-options "-Wno-switch-unreachable" } */ void foo (int a) diff --git gcc/testsuite/gcc.dg/pr67784-4.c gcc/testsuite/gcc.dg/pr67784-4.c index 81a43fd..5462080 100644 --- gcc/testsuite/gcc.dg/pr67784-4.c +++ gcc/testsuite/gcc.dg/pr67784-4.c @@ -1,6 +1,6 @@ /* PR c/67784 */ /* { dg-do compile } */ -/* { dg-options "" } */ +/* { dg-options "-Wno-switch-unreachable" } */ typedef int T; diff --git gcc/testsuite/gcc.dg/switch-warn-1.c gcc/testsuite/gcc.dg/switch-warn-1.c index 04ca4e3..58fbd7d 100644 --- gcc/testsuite/gcc.dg/switch-warn-1.c +++ gcc/testsuite/gcc.dg/switch-warn-1.c @@ -11,7 +11,7 @@ foo1 (unsigned char i) { switch (i) { - case -1: /* { dg-warning "case label value is less than minimum value for type" } */ + case -1: /* { dg-warning "case label value is less than minimum value for type|statement will never be executed" } */ return 1; case 256: /* { dg-warning "case label value exceeds maximum value for type" } */ return 2;