From ddfb80adbd91a0e45cc6e04a8b0dbe3ca15ba45f Mon Sep 17 00:00:00 2001 From: Uros Bizjak Date: Thu, 21 May 2020 19:36:32 +0200 Subject: [PATCH] i386: Avoid reversing a non-trapping comparison to a trapping one [PR95169] MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit 2020-05-21 Uroš Bizjak gcc/ChangeLog: PR target/95169 * config/i386/i386-expand.c (ix86_expand_int_movcc): Avoid reversing a non-trapping comparison to a trapping one. gcc/testsuite/ChangeLog: PR target/95169 * gcc.target/i386/pr95169.c: New test. --- gcc/ChangeLog | 6 ++++++ gcc/config/i386/i386-expand.c | 27 +++++++++++++++--------- gcc/testsuite/ChangeLog | 5 +++++ gcc/testsuite/gcc.target/i386/pr95169.c | 28 +++++++++++++++++++++++++ 4 files changed, 56 insertions(+), 10 deletions(-) create mode 100644 gcc/testsuite/gcc.target/i386/pr95169.c diff --git a/gcc/ChangeLog b/gcc/ChangeLog index be6787b08e9d..076b8f4c9063 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,9 @@ +2020-05-21 Uroš Bizjak + + PR target/95169 + * config/i386/i386-expand.c (ix86_expand_int_movcc): + Avoid reversing a non-trapping comparison to a trapping one. + 2020-05-21 Martin Liska * common/config/aarch64/aarch64-common.c (aarch64_handle_option): diff --git a/gcc/config/i386/i386-expand.c b/gcc/config/i386/i386-expand.c index 48f00c5fcfc6..6c759b01edf2 100644 --- a/gcc/config/i386/i386-expand.c +++ b/gcc/config/i386/i386-expand.c @@ -3059,11 +3059,14 @@ ix86_expand_int_movcc (rtx operands[]) { gcc_assert (!DECIMAL_FLOAT_MODE_P (cmp_mode)); - /* We may be reversing unordered compare to normal compare, that - is not valid in general (we may convert non-trapping condition - to trapping one), however on i386 we currently emit all - comparisons unordered. */ - new_code = reverse_condition_maybe_unordered (code); + /* We may be reversing a non-trapping + comparison to a trapping comparison. */ + if (HONOR_NANS (cmp_mode) && flag_trapping_math + && code != EQ && code != NE + && code != ORDERED && code != UNORDERED) + new_code = UNKNOWN; + else + new_code = reverse_condition_maybe_unordered (code); } else new_code = ix86_reverse_condition (code, cmp_mode); @@ -3215,11 +3218,15 @@ ix86_expand_int_movcc (rtx operands[]) { gcc_assert (!DECIMAL_FLOAT_MODE_P (cmp_mode)); - /* We may be reversing unordered compare to normal compare, - that is not valid in general (we may convert non-trapping - condition to trapping one), however on i386 we currently - emit all comparisons unordered. */ - new_code = reverse_condition_maybe_unordered (code); + /* We may be reversing a non-trapping + comparison to a trapping comparison. */ + if (HONOR_NANS (cmp_mode) && flag_trapping_math + && code != EQ && code != NE + && code != ORDERED && code != UNORDERED) + new_code = UNKNOWN; + else + new_code = reverse_condition_maybe_unordered (code); + } else { diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index 92a989fab087..74b4d088591f 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,8 @@ +2020-05-21 Uroš Bizjak + + PR target/95169 + * gcc.target/i386/pr95169.c: New test. + 2020-05-21 Martin Liska * gcc.target/aarch64/target_attr_20.c: New test. diff --git a/gcc/testsuite/gcc.target/i386/pr95169.c b/gcc/testsuite/gcc.target/i386/pr95169.c new file mode 100644 index 000000000000..91411744228e --- /dev/null +++ b/gcc/testsuite/gcc.target/i386/pr95169.c @@ -0,0 +1,28 @@ +/* PR target/95169 */ +/* { dg-do run { target ia32 } } */ +/* { dg-options "-O0 -march=i386 -mtune=generic" } */ +/* { dg-require-effective-target fenv_exceptions } */ + +#include + +void +f (double y) +{ + if (__builtin_expect (y == 0.0, 0)) + __builtin_abort (); +} + +int +main (void) +{ + double y = __builtin_nan (""); + + feclearexcept (FE_INVALID); + + f (y); + + if (fetestexcept (FE_INVALID)) + __builtin_abort (); + + return 0; +} -- 2.47.2