Clear restrict in install_var_field

2015-12-08  Tom de Vries  <tom@codesourcery.com>

	PR tree-optimization/68640
	* omp-low.c (install_var_field): Clear the restrict qualifier on the var
	type.

From-SVN: r231411

gcc/ChangeLog

+2015-12-08  Tom de Vries  <tom@codesourcery.com>
+
+	PR tree-optimization/68640
+	* omp-low.c (install_var_field): Clear the restrict qualifier on the var
+	type.
+
 2015-12-08  Kirill Yukhin  <kirill.yukhin@intel.com>
 
 	* config/i386/sse.md (define_insn "<avx512>_vec_dup<mode>_1"): Fix

gcc/omp-low.c

@@ -1389,6 +1389,13 @@ install_var_field (tree var, bool by_ref, int mask, omp_context *ctx,
 	      || !is_gimple_omp_oacc (ctx->stmt));
 
   type = TREE_TYPE (var);
+  /* Prevent redeclaring the var in the split-off function with a restrict
+     pointer type.  Note that we only clear type itself, restrict qualifiers in
+     the pointed-to type will be ignored by points-to analysis.  */
+  if (POINTER_TYPE_P (type)
+      && TYPE_RESTRICT (type))
+    type = build_qualified_type (type, TYPE_QUALS (type) & ~TYPE_QUAL_RESTRICT);
+
   if (mask & 4)
     {
       gcc_assert (TREE_CODE (type) == ARRAY_TYPE);

gcc/testsuite/gcc.dg/gomp/pr68640.c

+/* { dg-do compile } */
+/* { dg-options "-O2 -fopenmp -fdump-tree-ealias-all" } */
+
+#define N 1024
+
+int
+foo (int *__restrict__ ap)
+{
+  int *bp = ap;
+#pragma omp parallel for
+  for (unsigned int idx = 0; idx < N; idx++)
+    ap[idx] = bp[idx];
+}
+
+/* { dg-final { scan-tree-dump-times "clique 1 base 1" 2 "ealias" } } */
+/* { dg-final { scan-tree-dump-times "(?n)clique .* base .*" 2 "ealias" } } */