[gcc r16-9249] i386: Fix ccmp support checks for floating-point modes [PR126148]

https://gcc.gnu.org/g:c79762f15836588c1ed57bc8049c13a12e60b5db

commit r16-9249-gc79762f15836588c1ed57bc8049c13a12e60b5db
Author: Uros Bizjak <[email protected]>
Date:   Wed Jul 8 16:50:15 2026 +0200

    i386: Fix ccmp support checks for floating-point modes [PR126148]
    
    The ccmp expansion code allowed DFmode, SFmode and HFmode comparisons
    without verifying that the corresponding floating-point instruction
    set was available. This could result in attempts to generate ccmp
    sequences for comparisons that cannot be emitted as a single instruction
    under the selected target options.
    
    Restrict XFmode support to x87 targets, DFmode/SFmode support to
    targets with either x87 or SSE with SSE math enabled, and HFmode
    support to targets with AVX512FP16 enabled.
    
            PR target/126148
    
    gcc/ChangeLog:
    
            * config/i386/i386-expand.cc (ix86_gen_ccmp_first): Restrict
            floating-point modes accepted for ccmp according to the
            available floating-point instruction set.
    
    gcc/testsuite/ChangeLog:
    
            * gcc.target/i386/pr126148.c: New test.
    
    (cherry picked from commit c9e6fa83a85e8e86811bf03c71e607247397e082)

Diff:
---
 gcc/config/i386/i386-expand.cc           | 13 ++++++++-----
 gcc/testsuite/gcc.target/i386/pr126148.c |  8 ++++++++
 2 files changed, 16 insertions(+), 5 deletions(-)

diff --git a/gcc/config/i386/i386-expand.cc b/gcc/config/i386/i386-expand.cc
index 395f91ffdc33..b4763c703473 100644
--- a/gcc/config/i386/i386-expand.cc
+++ b/gcc/config/i386/i386-expand.cc
@@ -27061,12 +27061,15 @@ ix86_gen_ccmp_first (rtx_insn **prep_seq, rtx_insn **gen_seq,
     op_mode = GET_MODE (op1);
 
   /* We only supports following scalar comparisons that use just 1
-     instruction: DI/SI/QI/HI/DF/SF/HF.
-     Unordered/Ordered compare cannot be corretly indentified by
+     instruction: DI/SI/HI/QI/XF/DF/SF/HF.
+     Unordered/Ordered compare cannot be correctly identified by
      ccmp so they are not supported.  */
-  if (!(op_mode == DImode || op_mode == SImode || op_mode == HImode
-	|| op_mode == QImode || op_mode == DFmode || op_mode == SFmode
-	|| op_mode == HFmode)
+  if (!(op_mode == DImode || op_mode == SImode
+	|| op_mode == HImode || op_mode == QImode
+	|| ((op_mode == XFmode || op_mode == DFmode || op_mode == SFmode)
+	    && (TARGET_80387
+		|| (SSE_FLOAT_MODE_P (op_mode) && TARGET_SSE_MATH)))
+	|| (op_mode == HFmode && TARGET_AVX512FP16))
       || code == ORDERED
       || code == UNORDERED)
     {
diff --git a/gcc/testsuite/gcc.target/i386/pr126148.c b/gcc/testsuite/gcc.target/i386/pr126148.c
new file mode 100644
index 000000000000..f706d303c4d5
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr126148.c
@@ -0,0 +1,8 @@
+/* { dg-do compile { target { ! ia32 } } } */
+/* { dg-options "-O2 -ffast-math -mapxf -mno-80387 -mfpmath=387" } */
+
+int foo (int a, double b) {
+  if (a || b)
+    return 1;
+  return 0;
+}