[PATCH] Fix expansion of constants with -fsection-anchors (PR middle-end/52074)

[Jakub Jelinek]

Hi!

For EXPAND_NORMAL we shouldn't be returning (plus (reg) (const_int)),
that should be limited to EXPAND_SUM and higher modifiers.
But with -fsection-anchors we sometimes do.

Fixed thusly, bootstrapped/regtested on x86_64-linux and i686-linux,
tested with cross to powerpc64-linux on the testcase.  Ok for trunk?

2012-02-01  Jakub Jelinek  <ja...@redhat.com>

        PR middle-end/52074
        * expr.c (expand_expr_addr_expr_1): For CONSTANT_CLASS_P or CONST_DECL
        if modifier < EXPAND_SUM call force_operand on the result.

        * gcc.c-torture/compile/pr52074.c: New test.

--- gcc/expr.c.jj       2012-01-30 00:10:01.000000000 +0100
+++ gcc/expr.c  2012-02-01 13:00:03.468835769 +0100
@@ -7414,7 +7414,12 @@ expand_expr_addr_expr_1 (tree exp, rtx t
      generating ADDR_EXPR of something that isn't an LVALUE.  The only
      exception here is STRING_CST.  */
   if (CONSTANT_CLASS_P (exp))
-    return XEXP (expand_expr_constant (exp, 0, modifier), 0);
+    {
+      result = XEXP (expand_expr_constant (exp, 0, modifier), 0);
+      if (modifier < EXPAND_SUM)
+       result = force_operand (result, target);
+      return result;
+    }
 
   /* Everything must be something allowed by is_gimple_addressable.  */
   switch (TREE_CODE (exp))
@@ -7433,7 +7438,11 @@ expand_expr_addr_expr_1 (tree exp, rtx t
 
     case CONST_DECL:
       /* Expand the initializer like constants above.  */
-      return XEXP (expand_expr_constant (DECL_INITIAL (exp), 0, modifier), 0);
+      result = XEXP (expand_expr_constant (DECL_INITIAL (exp),
+                                          0, modifier), 0);
+      if (modifier < EXPAND_SUM)
+       result = force_operand (result, target);
+      return result;
 
     case REALPART_EXPR:
       /* The real part of the complex number is always first, therefore
--- gcc/testsuite/gcc.c-torture/compile/pr52074.c.jj    2012-02-01 
13:03:26.236788697 +0100
+++ gcc/testsuite/gcc.c-torture/compile/pr52074.c       2012-02-01 
13:03:07.000000000 +0100
@@ -0,0 +1,10 @@
+/* PR middle-end/52074 */
+
+struct S { const char *d, *e; } __attribute__((packed));
+
+void
+foo (const char **p, struct S *q)
+{
+  *p = "abcdef";
+  q->d = "ghijk";
+}

        Jakub