re PR tree-optimization/77808 (ICE in duplicate_ssa_name_ptr_info, at…

re PR tree-optimization/77808 (ICE in duplicate_ssa_name_ptr_info, at tree-ssanames.c:630 starting with r240439)

Fix PR tree-optimization/77808

gcc/
	PR tree-optimization/77808
	* tree-ssa-loop-prefetch.c (issue_prefetch_ref): Check base_addr
	and addr are different before copying points-to information.

gcc/testsuite/
	PR tree-optimization/77808
	* gcc.dg/tree-ssa/pr77808.c: New testcase.

From-SVN: r240749

gcc/ChangeLog

+2016-10-04  Doug Gilmore  <doug.gilmore@imgtec.com>
+
+	PR tree-optimization/77808
+	* tree-ssa-loop-prefetch.c (issue_prefetch_ref): Check base_addr
+	and addr are different before copying points-to information.
+
 2016-10-04  Uros Bizjak  <ubizjak@gmail.com>
 
 	* config/i386/x86-tune.def (X86_TUNE_VECTORIZE_DOUBLE): Remove.

gcc/testsuite/ChangeLog

+2016-10-04  Doug Gilmore  <doug.gilmore@imgtec.com>
+
+	PR tree-optimization/77808
+	* gcc.dg/tree-ssa/pr77808.c: New testcase.
+
 2016-10-04  Richard Biener  <rguenther@suse.de>
 
 	PR tree-optimization/77399

gcc/testsuite/gcc.dg/tree-ssa/pr77808.c

+/* PR tree-optimization/77808 */
+/* { dg-options "-O2 -fprefetch-loop-arrays --param prefetch-latency=0 -w" } */
+
+void
+daxpy(int n, double da, double * __restrict dx, double * __restrict dy)
+{
+  int i;
+
+  for (i = 0;i < n; i++)
+    dy[i] = dy[i] + da*dx[i];
+}

gcc/tree-ssa-loop-prefetch.c

@@ -1162,7 +1162,8 @@ issue_prefetch_ref (struct mem_ref *ref, unsigned unroll_factor, unsigned ahead)
 					   NULL, true, GSI_SAME_STMT);
       }
 
-      if (TREE_CODE (addr_base) == SSA_NAME
+      if (addr_base != addr
+	  && TREE_CODE (addr_base) == SSA_NAME
 	  && TREE_CODE (addr) == SSA_NAME)
 	{
 	  duplicate_ssa_name_ptr_info (addr, SSA_NAME_PTR_INFO (addr_base));