[PATCH] Fix PR79552

[Richard Biener]

The following fixes PR79552 on trunk (for the branch it would also need
backporting of r235147 to not regress PR48885 - its fix caused this
regression).

Bootstrapped on x86_64-unknown-linux-gnu, testing in progress.

Richard.

2017-02-17  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/79552
	* tree-ssa-structalias.c (visit_loadstore): Properly verify
	default defs.

Index: gcc/tree-ssa-structalias.c
===================================================================
--- gcc/tree-ssa-structalias.c	(revision 245501)
+++ gcc/tree-ssa-structalias.c	(working copy)
@@ -7296,9 +7312,15 @@ visit_loadstore (gimple *, tree base, tr
       || TREE_CODE (base) == TARGET_MEM_REF)
     {
       tree ptr = TREE_OPERAND (base, 0);
-      if (TREE_CODE (ptr) == SSA_NAME
-	  && ! SSA_NAME_IS_DEFAULT_DEF (ptr))
+      if (TREE_CODE (ptr) == SSA_NAME)
 	{
+	  /* For parameters, get at the points-to set for the actual parm
+	     decl.  */
+	  if (SSA_NAME_IS_DEFAULT_DEF (ptr)
+	      && (TREE_CODE (SSA_NAME_VAR (ptr)) == PARM_DECL
+		  || TREE_CODE (SSA_NAME_VAR (ptr)) == RESULT_DECL))
+	    ptr = SSA_NAME_VAR (ptr);
+
 	  /* We need to make sure 'ptr' doesn't include any of
 	     the restrict tags we added bases for in its points-to set.  */
 	  varinfo_t vi = lookup_vi_for_tree (ptr);