[gcc r16-3080] aarch64: Relax fpm_t assert to allow const_ints [PR120986]

[Alex Coplan via Gcc-cvs]

https://gcc.gnu.org/g:80b0e4ad2f60de8bd57e83628b4ead46df6fb004

commit r16-3080-g80b0e4ad2f60de8bd57e83628b4ead46df6fb004
Author: Alex Coplan <alex.cop...@arm.com>
Date:   Tue Jul 15 11:49:27 2025 +0100

    aarch64: Relax fpm_t assert to allow const_ints [PR120986]
    
    This relaxes an overzealous assert that required the fpm_t argument to
    be in DImode when expanding FP8 intrinsics.  Of course this fails to
    account for modeless const_ints.
    
    gcc/ChangeLog:
    
            PR target/120986
            * config/aarch64/aarch64-sve-builtins.cc
            (function_expander::expand): Relax fpm_t assert to allow
            modeless const_ints.
    
    gcc/testsuite/ChangeLog:
    
            PR target/120986
            * gcc.target/aarch64/torture/pr120986-2.c: New test.

Diff:
---
 gcc/config/aarch64/aarch64-sve-builtins.cc            | 5 +++--
 gcc/testsuite/gcc.target/aarch64/torture/pr120986-2.c | 7 +++++++
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/gcc/config/aarch64/aarch64-sve-builtins.cc 
b/gcc/config/aarch64/aarch64-sve-builtins.cc
index e394c9a84a04..1764cf8f7e8f 100644
--- a/gcc/config/aarch64/aarch64-sve-builtins.cc
+++ b/gcc/config/aarch64/aarch64-sve-builtins.cc
@@ -4590,8 +4590,9 @@ function_expander::expand ()
     {
       /* The last element of these functions is always an fpm_t that must be
          written to FPMR before the call to the instruction itself. */
-      gcc_assert (args.last ()->mode == DImode);
-      emit_move_insn (gen_rtx_REG (DImode, FPM_REGNUM), args.last ());
+      rtx fpm = args.last ();
+      gcc_assert (CONST_INT_P (fpm) || GET_MODE (fpm) == DImode);
+      emit_move_insn (gen_rtx_REG (DImode, FPM_REGNUM), fpm);
     }
   rtx result = base->expand (*this);
   if (function_returns_void_p ())
diff --git a/gcc/testsuite/gcc.target/aarch64/torture/pr120986-2.c 
b/gcc/testsuite/gcc.target/aarch64/torture/pr120986-2.c
new file mode 100644
index 000000000000..1218dead9ddb
--- /dev/null
+++ b/gcc/testsuite/gcc.target/aarch64/torture/pr120986-2.c
@@ -0,0 +1,7 @@
+/* { dg-do compile } */
+/* { dg-options "-march=armv8.2-a+sve2+fp8dot2" } */
+#include <arm_sve.h>
+svfloat16_t foo(svfloat16_t a, svmfloat8_t b, svmfloat8_t c)
+{
+  return svdot_lane_fpm (a, b, c, 0, 0);
+}