From: Richard Sandiford <richard.sandiford@arm.com>
Date: Fri, 7 Mar 2025 10:18:35 +0000 (+0000)
Subject: aarch64: Use force_lowpart_subreg in a BFI splitter [PR119133]
X-Git-Tag: basepoints/gcc-16~1673
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=5ae621e2e86c00d1fb13ef6839d0c3bace762ac8;p=thirdparty%2Fgcc.git

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 --git a/gcc/config/aarch64/aarch64.md b/gcc/config/aarch64/aarch64.md
index b10059e4f58..03188a64ab1 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 00000000000..78cdda69afe
--- /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;
+}