https://gcc.gnu.org/g:e3a60357520bc3d14a098ca748c49c44f97b03f5
commit r16-5978-ge3a60357520bc3d14a098ca748c49c44f97b03f5 Author: Richard Biener <[email protected]> Date: Mon Dec 8 10:14:19 2025 +0100 target/123027 - handle min/max expansion when -ffinite-math-only When we get a <= b ? b : a into ix86_expand_sse_fp_minmax we can swap and invert this with -ffinite-math-only to get a < b ? a : b. PR target/123027 * config/i386/i386-expand.cc (ix86_expand_sse_fp_minmax): With !HONOR_NANS we can handle LE by swapping and inverting. * gcc.target/i386/pr123027.c: New testcase. * gcc.dg/torture/pr123027.c: Likewise. Diff: --- gcc/config/i386/i386-expand.cc | 9 +++++++-- gcc/testsuite/gcc.dg/torture/pr123027.c | 20 ++++++++++++++++++++ gcc/testsuite/gcc.target/i386/pr123027.c | 15 +++++++++++++++ 3 files changed, 42 insertions(+), 2 deletions(-) diff --git a/gcc/config/i386/i386-expand.cc b/gcc/config/i386/i386-expand.cc index fd9bcaa8541a..438fa4e4b6af 100644 --- a/gcc/config/i386/i386-expand.cc +++ b/gcc/config/i386/i386-expand.cc @@ -4159,12 +4159,18 @@ static bool ix86_expand_sse_fp_minmax (rtx dest, enum rtx_code code, rtx cmp_op0, rtx cmp_op1, rtx if_true, rtx if_false) { - machine_mode mode; + machine_mode mode = GET_MODE (dest); bool is_min; rtx tmp; if (code == LT) ; + else if (code == LE && !HONOR_NANS (mode)) + { + /* We can swap LE to GE and then invert to LT. */ + std::swap (cmp_op0, cmp_op1); + std::swap (if_true, if_false); + } else if (code == UNGE) std::swap (if_true, if_false); else @@ -4177,7 +4183,6 @@ ix86_expand_sse_fp_minmax (rtx dest, enum rtx_code code, rtx cmp_op0, else return false; - mode = GET_MODE (dest); if (immediate_operand (if_false, mode)) if_false = force_reg (mode, if_false); if (immediate_operand (if_true, mode)) diff --git a/gcc/testsuite/gcc.dg/torture/pr123027.c b/gcc/testsuite/gcc.dg/torture/pr123027.c new file mode 100644 index 000000000000..cba4cc9792e8 --- /dev/null +++ b/gcc/testsuite/gcc.dg/torture/pr123027.c @@ -0,0 +1,20 @@ +/* { dg-do run } */ +/* { dg-options "-ffinite-math-only" } */ +/* { dg-add-options ieee } */ + +double a = 0.0; +double b = -0.0; + +int main() +{ + double min1 = a < b ? a : b; + double max1 = a > b ? a : b; + double min2 = b < a ? b : a; + double max2 = b > a ? b : a; + if (__builtin_copysign (1., min1) != -1. + || __builtin_copysign (1., max1) != -1. + || __builtin_copysign (1., min2) != 1. + || __builtin_copysign (1., max2) != 1.) + __builtin_abort (); + return 0; +} diff --git a/gcc/testsuite/gcc.target/i386/pr123027.c b/gcc/testsuite/gcc.target/i386/pr123027.c new file mode 100644 index 000000000000..b7effac99f7e --- /dev/null +++ b/gcc/testsuite/gcc.target/i386/pr123027.c @@ -0,0 +1,15 @@ +/* { dg-do compile } */ +/* { dg-options "-O2 -msse -mfpmath=sse -ffinite-math-only" } */ + +float foo (float a, float b) +{ + return a < b ? a : b; +} + +float bar (float a, float b) +{ + return a > b ? a : b; +} + +/* { dg-final { scan-assembler-times "minss" 1 } } */ +/* { dg-final { scan-assembler-times "maxss" 1 } } */
