gcc/ChangeLog: 2020-05-18 Uroš Bizjak <ubiz...@gmail.com>
PR target/95169 * config/i386/i386-expand.c (ix86_expand_int_movcc): Avoid reversing a non-trapping comparison to a trapping one. testsuite/ChangeLog: 2020-05-18 Uroš Bizjak <ubiz...@gmail.com> PR target/95169 * gcc.target/i386/pr95169.c: New test. Bootstrapped and regression tested on x86_64-linux-gnu {,-m32}. Uros.
diff --git a/gcc/config/i386/i386-expand.c b/gcc/config/i386/i386-expand.c index 2865cced66c..79f827fd653 100644 --- a/gcc/config/i386/i386-expand.c +++ b/gcc/config/i386/i386-expand.c @@ -3057,11 +3057,14 @@ 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); @@ -3213,11 +3216,15 @@ 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/gcc.target/i386/pr95169.c b/gcc/testsuite/gcc.target/i386/pr95169.c new file mode 100644 index 00000000000..91411744228 --- /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 <fenv.h> + +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; +}