[PATCH] tree-optimization/122370 - ICE with reduction and masks

[Richard Biener]

The following fixes bad interaction with mask demotion to data
and the code dealing with UB on signed reductions by making sure
to also update compute_vectype when updating vectype.

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

        PR tree-optimization/122370
        * tree-vect-loop.cc (vect_create_epilog_for_reduction):
        Also update compute_vectype when demoting masks to an
        integer vector.

        * gcc.dg/vect/vect-pr122370.c: New testcase.
---
 gcc/testsuite/gcc.dg/vect/vect-pr122370.c | 17 +++++++++++++++++
 gcc/tree-vect-loop.cc                     |  2 +-
 2 files changed, 18 insertions(+), 1 deletion(-)
 create mode 100644 gcc/testsuite/gcc.dg/vect/vect-pr122370.c

diff --git a/gcc/testsuite/gcc.dg/vect/vect-pr122370.c 
b/gcc/testsuite/gcc.dg/vect/vect-pr122370.c
new file mode 100644
index 00000000000..8e536bfb7c5
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/vect/vect-pr122370.c
@@ -0,0 +1,17 @@
+/* { dg-do compile } */
+/* { dg-additional-options "-mavx512vl -mavx512bw" { target { avx512vl && 
avx512bw } } } */
+
+bool f(bool splat, bool swizzle_splat,
+       int *elems, int length)
+{
+  int input = elems[0];
+  for (int i = 0; i < length; i++)
+    {
+      if (input != elems[i])
+       {
+         splat = false;
+         swizzle_splat = false;
+       }
+    }
+  return (splat && swizzle_splat);
+}
diff --git a/gcc/tree-vect-loop.cc b/gcc/tree-vect-loop.cc
index 617018f5aaf..77c9e15601b 100644
--- a/gcc/tree-vect-loop.cc
+++ b/gcc/tree-vect-loop.cc
@@ -5616,7 +5616,7 @@ vect_create_epilog_for_reduction (loop_vec_info 
loop_vinfo,
       && VECT_REDUC_INFO_VECTYPE_FOR_MASK (reduc_info)
       && vectype != VECT_REDUC_INFO_VECTYPE_FOR_MASK (reduc_info))
     {
-      vectype = VECT_REDUC_INFO_VECTYPE_FOR_MASK (reduc_info);
+      compute_vectype = vectype = VECT_REDUC_INFO_VECTYPE_FOR_MASK 
(reduc_info);
       gimple_seq stmts = NULL;
       for (unsigned i = 0; i < reduc_inputs.length (); ++i)
        reduc_inputs[i] = gimple_build (&stmts, VEC_COND_EXPR, vectype,
-- 
2.51.0