[PATCH] tree-optimization/95487 - use a truth type for scatter masks

[Richard Biener]

I am testing the following patch on x86_64-unknown-linux-gnu.  Test
coverage for autovectorization of scatters seems rare.

Richard.


This makes sure to get a truth type for scatter masks even when they
are invariant.

2020-06-03  Richard Biener  <rguent...@suse.de>

        PR tree-optimization/95487
        * tree-vect-stmts.c (vectorizable_store): Use a truth type
        for the scatter mask.

        * g++.dg/vect/pr95487.cc: New testcase.
---
 gcc/testsuite/g++.dg/vect/pr95487.cc | 20 ++++++++++++++++++++
 gcc/tree-vect-stmts.c                |  8 ++++++--
 2 files changed, 26 insertions(+), 2 deletions(-)
 create mode 100644 gcc/testsuite/g++.dg/vect/pr95487.cc

diff --git a/gcc/testsuite/g++.dg/vect/pr95487.cc 
b/gcc/testsuite/g++.dg/vect/pr95487.cc
new file mode 100644
index 00000000000..34023d25572
--- /dev/null
+++ b/gcc/testsuite/g++.dg/vect/pr95487.cc
@@ -0,0 +1,20 @@
+// { dg-do compile }
+// { dg-additional-options "-O3" }
+// { dg-additional-options "-march=skylake-avx512" { target x86_64-*-* 
i?86-*-* } }
+
+int a;
+bool d;
+char e;
+extern short f[];
+extern int g[];
+short j;
+void h() {
+  for (short b = j; b < 0; b += 2) {
+    f[b] = 0;
+    if (d) {
+      for (char c = 0; c < a; c += 3)
+        e = 0;
+      g[b] = 0;
+    }
+  }
+}
diff --git a/gcc/tree-vect-stmts.c b/gcc/tree-vect-stmts.c
index 10f2e394b1e..26121dfa79c 100644
--- a/gcc/tree-vect-stmts.c
+++ b/gcc/tree-vect-stmts.c
@@ -7668,8 +7668,12 @@ vectorizable_store (vec_info *vinfo,
                                                              gs_info.offset,
                                                              stmt_info);
              if (mask)
-               mask_op = vec_mask = vect_get_vec_def_for_operand (vinfo, mask,
-                                                                  stmt_info);
+               {
+                 tree mask_vectype = truth_type_for (vectype);
+                 mask_op = vec_mask
+                   = vect_get_vec_def_for_operand (vinfo, mask,
+                                                   stmt_info, mask_vectype);
+               }
            }
          else if (modifier != NONE && (j & 1))
            {
-- 
2.26.2