[committed] Fix predcom-3.c on arc-elf after vectorizer changes

[Jeff Law via Gcc-patches]

The change to turn on the vectorizer by default has caused predcom-3 to 
fail on arc-elf.

The test seems to want to verify that the loop was unrolled 3 times as 
part of the predcom pass.  Not surprisingly, vectorization changes the 
number of iterations and thus impacts unrolling decisions.

Given the test is expecting a specific amount of unrolling which is tied 
to the iterations, ISTM the best option in this case is to disable 
vectorization for this test.

Committed to the trunk,
Jeff
commit ebdf180e15d0ae18bfcb2bd822d7f096743cd4fb
Author: Jeff Law <jeffreya...@gmail.com>
Date:   Thu Oct 14 09:41:57 2021 -0400

    Fix predcom-3.c on arc-elf after vectorizer changes
    
    gcc/testsuite
            * gcc.dg/tree-ssa/predcom-3.c: Disable vectorizer.

diff --git a/gcc/testsuite/gcc.dg/tree-ssa/predcom-3.c 
b/gcc/testsuite/gcc.dg/tree-ssa/predcom-3.c
index 1174cd17eec..9abbe6c1380 100644
--- a/gcc/testsuite/gcc.dg/tree-ssa/predcom-3.c
+++ b/gcc/testsuite/gcc.dg/tree-ssa/predcom-3.c
@@ -1,5 +1,5 @@
 /* { dg-do compile } */
-/* { dg-options "-O2 -funroll-loops --param max-unroll-times=8 
-fpredictive-commoning -fdump-tree-pcom-details -fno-tree-pre" } */
+/* { dg-options "-O2 -funroll-loops --param max-unroll-times=8 
-fpredictive-commoning -fdump-tree-pcom-details -fno-tree-pre 
-fno-tree-loop-vectorize" } */
 
 int a[1000], b[1000];