| Message ID | 20190416074259.GY21066@tucnak |
|---|---|
| State | New |
| Headers | show |
| Series | Fix RTL DCE ICE (PR rtl-optimization/90082) | expand |
On Tue, 16 Apr 2019, Jakub Jelinek wrote: > Hi! > > Recently I've added an assert that if !can_alter_cfg DCE (fast DCE in that > case) doesn't actually alter the cfg. The following testcase shows > something where it still does. Even when a (const or pure) call doesn't > throw, it could have EDGE_ABNORMAL{,_CALL} edges added to setjmp etc. > The following patch makes sure we don't DCE such calls either if we can't > alter the cfg. > > Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk? OK. Richard. > 2019-04-16 Jakub Jelinek <jakub@redhat.com> > > PR rtl-optimization/90082 > * dce.c (can_delete_call): New function. > (deletable_insn_p, mark_insn): Use it. > > * gcc.dg/pr90082.c: New test. > > --- gcc/dce.c.jj 2019-04-12 18:19:47.134165696 +0200 > +++ gcc/dce.c 2019-04-15 12:17:40.746266503 +0200 > @@ -87,6 +87,32 @@ deletable_insn_p_1 (rtx body) > } > } > > +/* Don't delete calls that may throw if we cannot do so. */ > + > +static bool > +can_delete_call (rtx_insn *insn) > +{ > + if (cfun->can_delete_dead_exceptions && can_alter_cfg) > + return true; > + if (!insn_nothrow_p (insn)) > + return false; > + if (can_alter_cfg) > + return true; > + /* If we can't alter cfg, even when the call can't throw exceptions, it > + might have EDGE_ABNORMAL_CALL edges and so we shouldn't delete such > + calls. */ > + gcc_assert (CALL_P (insn)); > + if (BLOCK_FOR_INSN (insn) && BB_END (BLOCK_FOR_INSN (insn)) == insn) > + { > + edge e; > + edge_iterator ei; > + > + FOR_EACH_EDGE (e, ei, BLOCK_FOR_INSN (insn)->succs) > + if ((e->flags & EDGE_ABNORMAL_CALL) != 0) > + return false; > + } > + return true; > +} > > /* Return true if INSN is a normal instruction that can be deleted by > the DCE pass. */ > @@ -111,8 +137,7 @@ deletable_insn_p (rtx_insn *insn, bool f > && (RTL_CONST_OR_PURE_CALL_P (insn) > && !RTL_LOOPING_CONST_OR_PURE_CALL_P (insn)) > /* Don't delete calls that may throw if we cannot do so. */ > - && ((cfun->can_delete_dead_exceptions && can_alter_cfg) > - || insn_nothrow_p (insn))) > + && can_delete_call (insn)) > return find_call_stack_args (as_a <rtx_call_insn *> (insn), false, > fast, arg_stores); > > @@ -206,8 +231,7 @@ mark_insn (rtx_insn *insn, bool fast) > && !SIBLING_CALL_P (insn) > && (RTL_CONST_OR_PURE_CALL_P (insn) > && !RTL_LOOPING_CONST_OR_PURE_CALL_P (insn)) > - && ((cfun->can_delete_dead_exceptions && can_alter_cfg) > - || insn_nothrow_p (insn))) > + && can_delete_call (insn)) > find_call_stack_args (as_a <rtx_call_insn *> (insn), true, fast, NULL); > } > } > --- gcc/testsuite/gcc.dg/pr90082.c.jj 2019-04-15 12:22:01.662053468 +0200 > +++ gcc/testsuite/gcc.dg/pr90082.c 2019-04-15 12:22:41.638407968 +0200 > @@ -0,0 +1,13 @@ > +/* PR rtl-optimization/90082 */ > +/* { dg-do compile } */ > +/* { dg-options "-O1 -fnon-call-exceptions -ftrapv" } */ > + > +void *buf[5]; > + > +void > +foo (int a) > +{ > + if (__builtin_setjmp (buf) == 0) > + __asm__ ("" : : "n" (a * 2)); /* { dg-error "impossible constraint in 'asm'" } */ > + /* { dg-warning "asm operand 0 probably doesn't match constraints" "" { target *-*-* } .-1 } */ > +} > > Jakub >
--- gcc/dce.c.jj 2019-04-12 18:19:47.134165696 +0200 +++ gcc/dce.c 2019-04-15 12:17:40.746266503 +0200 @@ -87,6 +87,32 @@ deletable_insn_p_1 (rtx body) } } +/* Don't delete calls that may throw if we cannot do so. */ + +static bool +can_delete_call (rtx_insn *insn) +{ + if (cfun->can_delete_dead_exceptions && can_alter_cfg) + return true; + if (!insn_nothrow_p (insn)) + return false; + if (can_alter_cfg) + return true; + /* If we can't alter cfg, even when the call can't throw exceptions, it + might have EDGE_ABNORMAL_CALL edges and so we shouldn't delete such + calls. */ + gcc_assert (CALL_P (insn)); + if (BLOCK_FOR_INSN (insn) && BB_END (BLOCK_FOR_INSN (insn)) == insn) + { + edge e; + edge_iterator ei; + + FOR_EACH_EDGE (e, ei, BLOCK_FOR_INSN (insn)->succs) + if ((e->flags & EDGE_ABNORMAL_CALL) != 0) + return false; + } + return true; +} /* Return true if INSN is a normal instruction that can be deleted by the DCE pass. */ @@ -111,8 +137,7 @@ deletable_insn_p (rtx_insn *insn, bool f && (RTL_CONST_OR_PURE_CALL_P (insn) && !RTL_LOOPING_CONST_OR_PURE_CALL_P (insn)) /* Don't delete calls that may throw if we cannot do so. */ - && ((cfun->can_delete_dead_exceptions && can_alter_cfg) - || insn_nothrow_p (insn))) + && can_delete_call (insn)) return find_call_stack_args (as_a <rtx_call_insn *> (insn), false, fast, arg_stores); @@ -206,8 +231,7 @@ mark_insn (rtx_insn *insn, bool fast) && !SIBLING_CALL_P (insn) && (RTL_CONST_OR_PURE_CALL_P (insn) && !RTL_LOOPING_CONST_OR_PURE_CALL_P (insn)) - && ((cfun->can_delete_dead_exceptions && can_alter_cfg) - || insn_nothrow_p (insn))) + && can_delete_call (insn)) find_call_stack_args (as_a <rtx_call_insn *> (insn), true, fast, NULL); } } --- gcc/testsuite/gcc.dg/pr90082.c.jj 2019-04-15 12:22:01.662053468 +0200 +++ gcc/testsuite/gcc.dg/pr90082.c 2019-04-15 12:22:41.638407968 +0200 @@ -0,0 +1,13 @@ +/* PR rtl-optimization/90082 */ +/* { dg-do compile } */ +/* { dg-options "-O1 -fnon-call-exceptions -ftrapv" } */ + +void *buf[5]; + +void +foo (int a) +{ + if (__builtin_setjmp (buf) == 0) + __asm__ ("" : : "n" (a * 2)); /* { dg-error "impossible constraint in 'asm'" } */ + /* { dg-warning "asm operand 0 probably doesn't match constraints" "" { target *-*-* } .-1 } */ +}
Hi! Recently I've added an assert that if !can_alter_cfg DCE (fast DCE in that case) doesn't actually alter the cfg. The following testcase shows something where it still does. Even when a (const or pure) call doesn't throw, it could have EDGE_ABNORMAL{,_CALL} edges added to setjmp etc. The following patch makes sure we don't DCE such calls either if we can't alter the cfg. Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk? 2019-04-16 Jakub Jelinek <jakub@redhat.com> PR rtl-optimization/90082 * dce.c (can_delete_call): New function. (deletable_insn_p, mark_insn): Use it. * gcc.dg/pr90082.c: New test. Jakub