[PATCH] Fix PR54920

[Richard Biener]

This fixes PR54920.

Bootstrapped and tested on x86_64-unknown-linux-gnu, applied on
trunk and the 4.7 branch.

Richard.

2012-10-15  Richard Guenther  <rguent...@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.

Index: gcc/tree-ssa-pre.c
===================================================================
--- gcc/tree-ssa-pre.c  (revision 192398)
+++ gcc/tree-ssa-pre.c  (working copy)
@@ -2853,7 +2853,7 @@ create_expression_by_pieces (basic_block
     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)
          {
Index: gcc/testsuite/gcc.dg/torture/pr54920.c
===================================================================
--- gcc/testsuite/gcc.dg/torture/pr54920.c      (revision 0)
+++ gcc/testsuite/gcc.dg/torture/pr54920.c      (working copy)
@@ -0,0 +1,13 @@
+/* { 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 };
+}