From: Andrew Pinski <andrew.pinski@oss.qualcomm.com>
Date: Wed, 15 Oct 2025 16:59:25 +0000 (-0700)
Subject: riscv: Fix gimple folding of the vset* intrinsics [PR122270]
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=42f5f1004ff16ab25b97d3315a365614c68c6201;p=thirdparty%2Fgcc.git

riscv: Fix gimple folding of the vset* intrinsics [PR122270]

The problem here is that when the backend folds the vset intrinsics,
it tries to keep the lhs of the new statement to be the same as the old statement
due to the check in gsi_replace. The problem is with a MEM_REF vset::fold was
unsharing the new lhs here and using the original lhs in the other new statement.
This meant the check in gsi_replace would fail.
This fixes that oversight by switching around which statement gets the unshared
version.

Note the comment in vset::fold was already correct just not matching the code:
    /* Replace the call with two statements: a copy of the full tuple
       to the call result, followed by an update of the individual vector.

       The fold routines expect the replacement statement to have the
       same lhs as the original call, so return the copy statement
       rather than the field update.  */

Changes since v1:
* v2: Fix testcase.

	PR target/122270

gcc/ChangeLog:

	* config/riscv/riscv-vector-builtins-bases.cc (vset::fold): Use the
	unshare_expr for the statement that will be added seperately rather
	the one which will be used for the replacement.

gcc/testsuite/ChangeLog:

	* gcc.target/riscv/rvv/base/pr122270-1.c: New test.

Signed-off-by: Andrew Pinski <andrew.pinski@oss.qualcomm.com>
---

diff --git a/gcc/config/riscv/riscv-vector-builtins-bases.cc b/gcc/config/riscv/riscv-vector-builtins-bases.cc
index 7e4d396f05a..22b77ccd3d5 100644
--- a/gcc/config/riscv/riscv-vector-builtins-bases.cc
+++ b/gcc/config/riscv/riscv-vector-builtins-bases.cc
@@ -1793,12 +1793,13 @@ public:
        The fold routines expect the replacement statement to have the
        same lhs as the original call, so return the copy statement
        rather than the field update.  */
-    gassign *copy = gimple_build_assign (unshare_expr (f.lhs), rhs_tuple);
+    gassign *copy = gimple_build_assign (f.lhs, rhs_tuple);
 
     /* Get a reference to the individual vector.  */
     tree field = tuple_type_field (TREE_TYPE (f.lhs));
     tree lhs_array
-      = build3 (COMPONENT_REF, TREE_TYPE (field), f.lhs, field, NULL_TREE);
+      = build3 (COMPONENT_REF, TREE_TYPE (field), unshare_expr (f.lhs),
+		field, NULL_TREE);
     tree lhs_vector = build4 (ARRAY_REF, TREE_TYPE (rhs_vector), lhs_array,
 			      index, NULL_TREE, NULL_TREE);
     gassign *update = gimple_build_assign (lhs_vector, rhs_vector);
diff --git a/gcc/testsuite/gcc.target/riscv/rvv/base/pr122270-1.c b/gcc/testsuite/gcc.target/riscv/rvv/base/pr122270-1.c
new file mode 100644
index 00000000000..a026a7e16d7
--- /dev/null
+++ b/gcc/testsuite/gcc.target/riscv/rvv/base/pr122270-1.c
@@ -0,0 +1,10 @@
+/* { dg-options "" } */
+/* { dg-do compile } */
+/* { dg-add-options riscv_v } */
+/* PR target/122270 */
+
+#include "riscv_vector.h"
+
+void a(vfloat32m1_t b, vfloat32m1x4_t *c) {
+  *c = __riscv_vset_v_f32m1_f32m1x4(*c, 3, b);
+}