re PR tree-optimization/80359 (DSE causes error: invalid reference prefix)

2017-04-12  Richard Biener  <rguenther@suse.de>
	Jeff Law  <law@redhat.com>

	PR tree-optimization/80359
	* tree-ssa-dse.c (maybe_trim_partially_dead_store): Do not
	trim stores to TARGET_MEM_REFs.

	* gcc.dg/torture/pr80359.c: New testcase.

Co-Authored-By: Jeff Law <law@redhat.com>

From-SVN: r246875

gcc/ChangeLog

 2017-04-12  Richard Biener  <rguenther@suse.de>
+	Jeff Law  <law@redhat.com>
+
+	PR tree-optimization/80359
+	* tree-ssa-dse.c (maybe_trim_partially_dead_store): Do not
+	trim stores to TARGET_MEM_REFs.
+
+2017-04-12  Richard Biener  <rguenther@suse.de>
 
 	PR tree-optimization/79390
 	* gimple-ssa-split-paths.c (is_feasible_trace): Restrict

gcc/testsuite/ChangeLog

 2017-04-12  Richard Biener  <rguenther@suse.de>
+	Jeff Law  <law@redhat.com>
+
+	PR tree-optimization/80359
+	* gcc.dg/torture/pr80359.c: New testcase.
+
+2017-04-12  Richard Biener  <rguenther@suse.de>
 	Bernd Edlinger  <bernd.edlinger@hotmail.de>
 
 	PR middle-end/79671

gcc/testsuite/gcc.dg/torture/pr80359.c

+/* { dg-do compile } */
+
+void FFT(_Complex *X, int length)
+{
+  unsigned i, j;
+  for (; i < length; i++)
+    {
+      X[i] = 0;
+      for (j = 0; j < length; j++)
+	X[i] = X[i] / length;
+    }
+}

gcc/tree-ssa-dse.c

@@ -451,7 +451,8 @@ maybe_trim_memstar_call (ao_ref *ref, sbitmap live, gimple *stmt)
 static void
 maybe_trim_partially_dead_store (ao_ref *ref, sbitmap live, gimple *stmt)
 {
-  if (is_gimple_assign (stmt))
+  if (is_gimple_assign (stmt)
+      && TREE_CODE (gimple_assign_lhs (stmt)) != TARGET_MEM_REF)
     {
       switch (gimple_assign_rhs_code (stmt))
 	{