[PATCH] tree-optimization/95297 - handle scalar shift arg for SLP invariant vectype

[Richard Biener]

This skips invariant vector type setting for a scalar shift argument.

Bootstrapped and tested on x86_64-unknown-linux-gnu, applied.

Richard.

2020-05-25  Richard Biener  <rguent...@suse.de>

        PR tree-optimization/95297
        * tree-vect-stmts.c (vectorizable_shift): For scalar_shift_arg
        skip updating operand 1 vector type.

        * g++.dg/vect/pr95297.cc: New testcase.
---
 gcc/testsuite/g++.dg/vect/pr95297.cc | 22 ++++++++++++++++++++++
 gcc/tree-vect-stmts.c                |  3 ++-
 2 files changed, 24 insertions(+), 1 deletion(-)
 create mode 100644 gcc/testsuite/g++.dg/vect/pr95297.cc

diff --git a/gcc/testsuite/g++.dg/vect/pr95297.cc 
b/gcc/testsuite/g++.dg/vect/pr95297.cc
new file mode 100644
index 00000000000..6ffc92e5fd0
--- /dev/null
+++ b/gcc/testsuite/g++.dg/vect/pr95297.cc
@@ -0,0 +1,22 @@
+// { dg-do compile }
+// { dg-additional-options "-O3 -fvect-cost-model=dynamic" }
+
+extern bool var_10;
+extern int var_16;
+extern short var_17;
+extern long var_18;
+extern int arr_3[][13];
+
+int min(const int &a, const int &b)
+{
+  return a < b ? a : b;
+}
+
+void test() {
+    for (short a = 0; a < 010; a++)
+      for (char b = 0; b < 012; b++)
+       arr_3[a][b] = min(-var_10, 0) + 2147483647 >> var_10;
+    var_16 = (bool)4;
+    var_17 = 0;
+    var_18 = -1594153176;
+}
diff --git a/gcc/tree-vect-stmts.c b/gcc/tree-vect-stmts.c
index 9023dd4c216..76c7b995817 100644
--- a/gcc/tree-vect-stmts.c
+++ b/gcc/tree-vect-stmts.c
@@ -5784,7 +5784,8 @@ vectorizable_shift (vec_info *vinfo,
     {
       if (slp_node
          && (!vect_maybe_update_slp_op_vectype (slp_op0, vectype)
-             || !vect_maybe_update_slp_op_vectype (slp_op1, op1_vectype)))
+             || (!scalar_shift_arg
+                 && !vect_maybe_update_slp_op_vectype (slp_op1, op1_vectype))))
        {
          if (dump_enabled_p ())
            dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
-- 
2.25.1