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>
(cherry picked from commit 42f5f1004ff16ab25b97d3315a365614c68c6201)

diff --git a/gcc/config/riscv/riscv-vector-builtins-bases.cc b/gcc/config/riscv/riscv-vector-builtins-bases.cc
index bf5172c6e041a640125fbfe870c2a420119b8fa4..5ccb872df639d635ba8c5cadaab02f45b5593274 100644 (file)
--- a/gcc/config/riscv/riscv-vector-builtins-bases.cc
+++ b/gcc/config/riscv/riscv-vector-builtins-bases.cc
@@ -1792,12 +1792,13 @@ 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 (file)
index 0000000..a026a7e
--- /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);
+}