[gcc r13-1502] tree-optimization/106196 - properly update virtual SSA for vector stores

[gcc r13-1502] tree-optimization/106196 - properly update virtual SSA for vector stores

[Richard Biener]

https://gcc.gnu.org/g:1a6e0d8252a71c61d4dc616044fb25b5ac2cfffb

commit r13-1502-g1a6e0d8252a71c61d4dc616044fb25b5ac2cfffb
Author: Richard Biener <rguenther@suse.de>
Date:   Tue Jul 5 10:43:42 2022 +0200

    tree-optimization/106196 - properly update virtual SSA for vector stores
    
    The following properly handles aggregate returns of the const marked
    STORE_LANES internal function to update virtual SSA form on-the-fly
    rather than relying on a costly virtual SSA rewrite.
    
            PR tree-optimization/106196
            * tree-vect-stmts.cc (vect_finish_stmt_generation): Properly
            handle aggregate returns of calls for VDEF updates.
    
            * gcc.dg/torture/pr106196.c: New testcase.

Diff:
---
 gcc/testsuite/gcc.dg/torture/pr106196.c | 14 ++++++++++++++
 gcc/tree-vect-stmts.cc                  |  6 ++++--
 2 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/gcc/testsuite/gcc.dg/torture/pr106196.c b/gcc/testsuite/gcc.dg/torture/pr106196.c
new file mode 100644
index 00000000000..56723de42c2
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr106196.c
@@ -0,0 +1,14 @@
+/* { dg-do compile } */
+/* { dg-additional-options "-ftree-vectorize -fno-vect-cost-model" } */
+
+extern char a[];
+char *b;
+void e() {
+  char *d;
+  int c;
+  d = a;
+  for (; c; c++) {
+    d[2] = d[1] = d[0] = b[c];
+    d += 3;
+  }
+}
diff --git a/gcc/tree-vect-stmts.cc b/gcc/tree-vect-stmts.cc
index 72107afc883..3db6620dd42 100644
--- a/gcc/tree-vect-stmts.cc
+++ b/gcc/tree-vect-stmts.cc
@@ -1638,8 +1638,10 @@ vect_finish_stmt_generation (vec_info *vinfo,
 	      && ((is_gimple_assign (vec_stmt)
 		   && !is_gimple_reg (gimple_assign_lhs (vec_stmt)))
 		  || (is_gimple_call (vec_stmt)
-		      && !(gimple_call_flags (vec_stmt)
-			   & (ECF_CONST|ECF_PURE|ECF_NOVOPS)))))
+		      && (!(gimple_call_flags (vec_stmt)
+			    & (ECF_CONST|ECF_PURE|ECF_NOVOPS))
+			  || (gimple_call_lhs (vec_stmt)
+			      && !is_gimple_reg (gimple_call_lhs (vec_stmt)))))))
 	    {
 	      tree new_vdef = copy_ssa_name (vuse, vec_stmt);
 	      gimple_set_vdef (vec_stmt, new_vdef);