[PATCH] Fix wrong-code at -O0 with MEM_REF in initializer (PR middle-end/53084)

[Jakub Jelinek]

Hi!

output_addressed_constants isn't able to output constants addressed
with &MEM_REF<&something, X> and similarly compute_reloc_for_constant
doesn't handle it.  Fixed thusly, bootstrapped/regtested on x86_64-linux and
i686-linux, ok for trunk/4.7?

2012-04-23  Jakub Jelinek  <ja...@redhat.com>

        PR middle-end/53084
        * varasm.c (compute_reloc_for_constant): Handle ADDR_EXPR
        of MEM_REF.
        (output_addressed_constants): Likewise.

        * gcc.c-torture/execute/pr53084.c: New test.

--- gcc/varasm.c.jj     2012-04-23 18:55:46.000000000 +0200
+++ gcc/varasm.c        2012-04-23 20:26:15.930660033 +0200
@@ -3948,6 +3948,13 @@ compute_reloc_for_constant (tree exp)
           tem = TREE_OPERAND (tem, 0))
        ;
 
+      if (TREE_CODE (tem) == MEM_REF
+         && TREE_CODE (TREE_OPERAND (tem, 0)) == ADDR_EXPR)
+       {
+         reloc = compute_reloc_for_constant (TREE_OPERAND (tem, 0));
+         break;
+       }
+
       if (TREE_PUBLIC (tem))
        reloc |= 2;
       else
@@ -4016,6 +4023,9 @@ output_addressed_constants (tree exp)
 
       if (CONSTANT_CLASS_P (tem) || TREE_CODE (tem) == CONSTRUCTOR)
        output_constant_def (tem, 0);
+
+      if (TREE_CODE (tem) == MEM_REF)
+       output_addressed_constants (TREE_OPERAND (tem, 0));
       break;
 
     case PLUS_EXPR:
--- gcc/testsuite/gcc.c-torture/execute/pr53084.c       2012-04-16 
20:35:50.603036390 +0200
+++ gcc/testsuite/gcc.c-torture/execute/pr53084.c       2012-04-23 
20:30:57.193896339 +0200
@@ -0,0 +1,18 @@
+/* PR middle-end/53084 */
+
+extern void abort (void);
+
+__attribute__((noinline, noclone)) void
+bar (const char *p)
+{
+  if (p[0] != 'o' || p[1] != 'o' || p[2])
+    abort ();
+}
+
+int
+main ()
+{
+  static const char *const foo[] = {"foo" + 1};
+  bar (foo[0]);
+  return 0;
+}

        Jakub