| Message ID | 20171221175451.GB2353@tucnak |
|---|---|
| State | New |
| Headers | show |
| Series | Fix ICE with widen_mult and -ftrapv (PR tree-optimization/83523) | expand |
On December 21, 2017 6:54:51 PM GMT+01:00, Jakub Jelinek <jakub@redhat.com> wrote: >Hi! > >Converting widening mult, or widen_{plus,minus}_expr, or integral mult >to >fma is IMNSHO undesirable with -ftrapv for signed types - the expansion >of >those doesn't detect overflows and by giving up we don't need to worry >about >formerly trapping MULT_EXPR becoming something that isn't trapping and >performing EH cleanups etc. > >Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk? OK. Richard. >2017-12-21 Jakub Jelinek <jakub@redhat.com> > > PR tree-optimization/83523 > * tree-ssa-math-opts.c (is_widening_mult_p): Return false if > for INTEGER_TYPE TYPE_OVERFLOW_TRAPS. > (convert_mult_to_fma): Likewise. > > * g++.dg/tree-ssa/pr83523.C: New test. > >--- gcc/tree-ssa-math-opts.c.jj 2017-12-21 09:43:19.000000000 +0100 >+++ gcc/tree-ssa-math-opts.c 2017-12-21 12:22:10.576488270 +0100 >@@ -2196,8 +2196,12 @@ is_widening_mult_p (gimple *stmt, > { > tree type = TREE_TYPE (gimple_assign_lhs (stmt)); > >- if (TREE_CODE (type) != INTEGER_TYPE >- && TREE_CODE (type) != FIXED_POINT_TYPE) >+ if (TREE_CODE (type) == INTEGER_TYPE) >+ { >+ if (TYPE_OVERFLOW_TRAPS (type)) >+ return false; >+ } >+ else if (TREE_CODE (type) != FIXED_POINT_TYPE) > return false; > >if (!is_widening_mult_rhs_p (type, gimple_assign_rhs1 (stmt), >type1_out, >@@ -2656,7 +2660,7 @@ convert_mult_to_fma (gimple *mul_stmt, t > > /* We don't want to do bitfield reduction ops. */ > if (INTEGRAL_TYPE_P (type) >- && !type_has_mode_precision_p (type)) >+ && (!type_has_mode_precision_p (type) || TYPE_OVERFLOW_TRAPS >(type))) > return false; > >/* If the target doesn't support it, don't generate it. We assume that >--- gcc/testsuite/g++.dg/tree-ssa/pr83523.C.jj 2017-12-21 >12:20:56.555403891 +0100 >+++ gcc/testsuite/g++.dg/tree-ssa/pr83523.C 2017-12-21 >12:20:02.000000000 +0100 >@@ -0,0 +1,25 @@ >+// PR tree-optimization/83523 >+// { dg-do compile } >+// { dg-options "-O2 -fexceptions -fnon-call-exceptions -ftrapv" } >+ >+#ifdef __SIZEOF_INT128__ >+typedef __int128 T; >+typedef long long int U; >+#else >+typedef long long int T; >+typedef int U; >+#endif >+ >+struct S { S (); ~S (); }; >+void bar (); >+ >+T >+foo (U x, U y) >+{ >+ T z = x; >+ S s; >+ bar (); >+ z *= y; >+ bar (); >+ return z; >+} > > Jakub
On 12/21/2017 10:54 AM, Jakub Jelinek wrote: > Hi! > > Converting widening mult, or widen_{plus,minus}_expr, or integral mult to > fma is IMNSHO undesirable with -ftrapv for signed types - the expansion of > those doesn't detect overflows and by giving up we don't need to worry about > formerly trapping MULT_EXPR becoming something that isn't trapping and > performing EH cleanups etc. > > Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk? > > 2017-12-21 Jakub Jelinek <jakub@redhat.com> > > PR tree-optimization/83523 > * tree-ssa-math-opts.c (is_widening_mult_p): Return false if > for INTEGER_TYPE TYPE_OVERFLOW_TRAPS. > (convert_mult_to_fma): Likewise. > > * g++.dg/tree-ssa/pr83523.C: New test. OK. jeff
--- gcc/tree-ssa-math-opts.c.jj 2017-12-21 09:43:19.000000000 +0100 +++ gcc/tree-ssa-math-opts.c 2017-12-21 12:22:10.576488270 +0100 @@ -2196,8 +2196,12 @@ is_widening_mult_p (gimple *stmt, { tree type = TREE_TYPE (gimple_assign_lhs (stmt)); - if (TREE_CODE (type) != INTEGER_TYPE - && TREE_CODE (type) != FIXED_POINT_TYPE) + if (TREE_CODE (type) == INTEGER_TYPE) + { + if (TYPE_OVERFLOW_TRAPS (type)) + return false; + } + else if (TREE_CODE (type) != FIXED_POINT_TYPE) return false; if (!is_widening_mult_rhs_p (type, gimple_assign_rhs1 (stmt), type1_out, @@ -2656,7 +2660,7 @@ convert_mult_to_fma (gimple *mul_stmt, t /* We don't want to do bitfield reduction ops. */ if (INTEGRAL_TYPE_P (type) - && !type_has_mode_precision_p (type)) + && (!type_has_mode_precision_p (type) || TYPE_OVERFLOW_TRAPS (type))) return false; /* If the target doesn't support it, don't generate it. We assume that --- gcc/testsuite/g++.dg/tree-ssa/pr83523.C.jj 2017-12-21 12:20:56.555403891 +0100 +++ gcc/testsuite/g++.dg/tree-ssa/pr83523.C 2017-12-21 12:20:02.000000000 +0100 @@ -0,0 +1,25 @@ +// PR tree-optimization/83523 +// { dg-do compile } +// { dg-options "-O2 -fexceptions -fnon-call-exceptions -ftrapv" } + +#ifdef __SIZEOF_INT128__ +typedef __int128 T; +typedef long long int U; +#else +typedef long long int T; +typedef int U; +#endif + +struct S { S (); ~S (); }; +void bar (); + +T +foo (U x, U y) +{ + T z = x; + S s; + bar (); + z *= y; + bar (); + return z; +}
Hi! Converting widening mult, or widen_{plus,minus}_expr, or integral mult to fma is IMNSHO undesirable with -ftrapv for signed types - the expansion of those doesn't detect overflows and by giving up we don't need to worry about formerly trapping MULT_EXPR becoming something that isn't trapping and performing EH cleanups etc. Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk? 2017-12-21 Jakub Jelinek <jakub@redhat.com> PR tree-optimization/83523 * tree-ssa-math-opts.c (is_widening_mult_p): Return false if for INTEGER_TYPE TYPE_OVERFLOW_TRAPS. (convert_mult_to_fma): Likewise. * g++.dg/tree-ssa/pr83523.C: New test. Jakub