re PR tree-optimization/32810 (Not folding of const element for goto)

2008-03-27  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/32810
	* tree-ssa-ccp.c (get_symbol_constant_value): Strip useless
	conversions from DECL_INITIAL.
	(fold_const_aggregate_ref): Likewise from constructor elements.

	* gcc.dg/tree-ssa/ssa-ccp-18.c: New testcase.

From-SVN: r133645

gcc/ChangeLog

+2008-03-27  Richard Guenther  <rguenther@suse.de>
+
+	PR tree-optimization/32810
+	* tree-ssa-ccp.c (get_symbol_constant_value): Strip useless
+	conversions from DECL_INITIAL.
+	(fold_const_aggregate_ref): Likewise from constructor elements.
+
 2008-03-27  Zdenek Dvorak  <ook@ucw.cz>
 
 	* tree-affine.h (aff_combination_expand): Declare.

gcc/testsuite/ChangeLog

+2008-03-27  Richard Guenther  <rguenther@suse.de>
+
+	PR tree-optimization/32810
+	* gcc.dg/tree-ssa/ssa-ccp-18.c: New testcase.
+
 2008-03-27  Douglas Gregor  <doug.gregor@gmail.com>
 
        * g++.dg/cpp0x/variadic91.C: New.

gcc/testsuite/gcc.dg/tree-ssa/ssa-ccp-18.c

+/* { dg-do compile } */
+/* { dg-options "-O -fdump-tree-ccp1" } */
+
+/* Check that we constant propagate &&c into the goto and remove
+   the unreachable BBs.  */
+
+void a(int*);  void b(int*);  void c(int*);  void d(int*);
+void func2(int* val)
+{
+  const void *const labels[] = { &&a, &&b, &&c, &&d };
+  goto *labels[2];
+  a: a(val);
+  b: b(val);
+  c: c(val);
+  d: d(val);
+}
+
+/* { dg-final { scan-tree-dump-not "a \\\(" "ccp1" } } */
+/* { dg-final { scan-tree-dump-not "b \\\(" "ccp1" } } */
+/* { dg-final { cleanup-tree-dump "ccp1" } } */

gcc/tree-ssa-ccp.c

@@ -278,9 +278,12 @@ get_symbol_constant_value (tree sym)
       && !MTAG_P (sym))
     {
       tree val = DECL_INITIAL (sym);
-      if (val
-	  && is_gimple_min_invariant (val))
-	return val;
+      if (val)
+	{
+	  STRIP_USELESS_TYPE_CONVERSION (val);
+	  if (is_gimple_min_invariant (val))
+	    return val;
+	}
       /* Variables declared 'const' without an initializer
 	 have zero as the intializer if they may not be
 	 overridden at link or run time.  */
@@ -1104,7 +1107,10 @@ fold_const_aggregate_ref (tree t)
       /* Whoo-hoo!  I'll fold ya baby.  Yeah!  */
       FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (ctor), cnt, cfield, cval)
 	if (tree_int_cst_equal (cfield, idx))
-	  return cval;
+	  {
+	    STRIP_USELESS_TYPE_CONVERSION (cval);
+	    return cval;
+	  }
       break;
 
     case COMPONENT_REF:
@@ -1144,7 +1150,10 @@ fold_const_aggregate_ref (tree t)
 	if (cfield == field
 	    /* FIXME: Handle bit-fields.  */
 	    && ! DECL_BIT_FIELD (cfield))
-	  return cval;
+	  {
+	    STRIP_USELESS_TYPE_CONVERSION (cval);
+	    return cval;
+	  }
       break;
 
     case REALPART_EXPR: