[gcc r15-7880] aarch64: Use force_lowpart_subreg in a BFI splitter [PR119133]

[Richard Sandiford via Gcc-cvs]

https://gcc.gnu.org/g:5ae621e2e86c00d1fb13ef6839d0c3bace762ac8

commit r15-7880-g5ae621e2e86c00d1fb13ef6839d0c3bace762ac8
Author: Richard Sandiford <richard.sandif...@arm.com>
Date:   Fri Mar 7 10:18:35 2025 +0000

    aarch64: Use force_lowpart_subreg in a BFI splitter [PR119133]
    
    lowpart_subreg ICEs are the gift that keeps giving.  This is another
    case where we need to use force_lowpart_subreg instead, to handle
    cases where the input is already a subreg and where the combined
    subreg is not allowed as a single operation.
    
    We don't need to check can_create_pseudo_p since the input should
    be a hard register rather than a subreg if !can_create_pseudo_p.
    
    gcc/
            PR target/119133
            * config/aarch64/aarch64.md
            (*aarch64_bfi<GPI:mode><ALLX:mode>_<SUBDI_BITS>): Use
            force_lowpart_subreg.
    
    gcc/testsuite/
            PR target/119133
            * gcc.dg/torture/pr119133.c: New test.

Diff:
---
 gcc/config/aarch64/aarch64.md           | 4 ++--
 gcc/testsuite/gcc.dg/torture/pr119133.c | 8 ++++++++
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/gcc/config/aarch64/aarch64.md b/gcc/config/aarch64/aarch64.md
index b10059e4f580..03188a64ab17 100644
--- a/gcc/config/aarch64/aarch64.md
+++ b/gcc/config/aarch64/aarch64.md
@@ -6435,8 +6435,8 @@
                          (match_dup 1))
        (match_dup 2))]
   {
-    operands[2] = lowpart_subreg (<GPI:MODE>mode, operands[2],
-                                 <ALLX:MODE>mode);
+    operands[2] = force_lowpart_subreg (<GPI:MODE>mode, operands[2],
+                                       <ALLX:MODE>mode);
   }
   [(set_attr "type" "bfm,neon_ins_q,neon_ins_q")
    (set_attr "arch" "*,simd,simd")]
diff --git a/gcc/testsuite/gcc.dg/torture/pr119133.c 
b/gcc/testsuite/gcc.dg/torture/pr119133.c
new file mode 100644
index 000000000000..78cdda69afed
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr119133.c
@@ -0,0 +1,8 @@
+/* { dg-additional-options "-fno-tree-ter" } */
+
+int
+foo(_Float16 f, int i)
+{
+  __builtin_memcpy(&i, &f, 2);
+  return i;
+}