re PR tree-optimization/54920 (segfault in tree-ssa-pre.c during Firefox build)

2012-10-15  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/54920
	* tree-ssa-pre.c (create_expression_by_pieces): Properly
	allocate temporary storage for all NARY elements.

	* gcc.dg/torture/pr54920.c: New testcase.

From-SVN: r192454

gcc/ChangeLog

+2012-10-15  Richard Guenther  <rguenther@suse.de>
+
+	PR tree-optimization/54920
+	* tree-ssa-pre.c (create_expression_by_pieces): Properly
+	allocate temporary storage for all NARY elements.
+
 2012-10-15  Joern Rennecke  <joern.rennecke@embecosm.com>
 
 	* web.c (union_match_dups): Properly handle OP_INOUT match_dups.

gcc/testsuite/ChangeLog

+2012-10-15  Richard Guenther  <rguenther@suse.de>
+
+	PR tree-optimization/54920
+	* gcc.dg/torture/pr54920.c: New testcase.
+
 2012-10-15  Eric Botcazou  <ebotcazou@adacore.com>
 
 	* gnat.dg/unchecked_convert9.ad[sb]: New test.

gcc/testsuite/gcc.dg/torture/pr54920.c

+/* { dg-do compile } */
+
+typedef short __v8hi __attribute__ ((__vector_size__ (16)));
+typedef long long __m128i __attribute__ ((__vector_size__ (16)));
+int a;
+__m128i b;
+
+void
+fn1 ()
+{
+  while (1)
+    b = (__m128i) (__v8hi) { a, 0, 0, 0, 0, 0 };
+}

gcc/tree-ssa-pre.c

@@ -2853,7 +2853,7 @@ create_expression_by_pieces (basic_block block, pre_expr expr,
     case NARY:
       {
 	vn_nary_op_t nary = PRE_EXPR_NARY (expr);
-	tree genop[4];
+	tree *genop = XALLOCAVEC (tree, nary->length);
 	unsigned i;
 	for (i = 0; i < nary->length; ++i)
 	  {