[gcc r14-11633] aarch64: Use force_lowpart_subreg in a BFI splitter [PR119133]

[Richard Sandiford via Gcc-cvs]

https://gcc.gnu.org/g:17cce5f59a4d9cdb87f59c6841da89c9ea2ef8d5

commit r14-11633-g17cce5f59a4d9cdb87f59c6841da89c9ea2ef8d5
Author: Richard Sandiford <richard.sandif...@arm.com>
Date:   Wed Apr 16 13:20:27 2025 +0100

    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.
    
    (cherry picked from commit 5ae621e2e86c00d1fb13ef6839d0c3bace762ac8)

Diff:
---
 gcc/config/aarch64/aarch64.md           |  4 ++--
 gcc/testsuite/gcc.dg/torture/pr119133.c | 10 ++++++++++
 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/gcc/config/aarch64/aarch64.md b/gcc/config/aarch64/aarch64.md
index d3c381e82ce4..1be8322c4ee0 100644
--- a/gcc/config/aarch64/aarch64.md
+++ b/gcc/config/aarch64/aarch64.md
@@ -6161,8 +6161,8 @@
                          (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..f0c8f734c866
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr119133.c
@@ -0,0 +1,10 @@
+/* { dg-additional-options "-fno-tree-ter" } */
+/* { dg-require-effective-target float16 } */
+/* { dg-add-options float16 } */
+
+int
+foo(_Float16 f, int i)
+{
+  __builtin_memcpy(&i, &f, 2);
+  return i;
+}