glsl: Consolidate duplicate copies of constant folding.

We could probably clean this up more (maybe make it a method), but at
least there's only one copy of this code now, and that's a start.

No change in shader-db.

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>

src/compiler/glsl/opt_constant_propagation.cpp

@@ -136,33 +136,10 @@ public:
 
 
 void
-ir_constant_propagation_visitor::constant_folding(ir_rvalue **rvalue) {
-
-   if (*rvalue == NULL || (*rvalue)->ir_type == ir_type_constant)
-      return;
-
-   /* Note that we visit rvalues one leaving.  So if an expression has a
-    * non-constant operand, no need to go looking down it to find if it's
-    * constant.  This cuts the time of this pass down drastically.
-    */
-   ir_expression *expr = (*rvalue)->as_expression();
-   if (expr) {
-      for (unsigned int i = 0; i < expr->get_num_operands(); i++) {
-	 if (!expr->operands[i]->as_constant())
-	    return;
-      }
-   }
-
-   /* Ditto for swizzles. */
-   ir_swizzle *swiz = (*rvalue)->as_swizzle();
-   if (swiz && !swiz->val->as_constant())
-      return;
-
-   ir_constant *constant = (*rvalue)->constant_expression_value();
-   if (constant) {
-      *rvalue = constant;
+ir_constant_propagation_visitor::constant_folding(ir_rvalue **rvalue)
+{
+   if (ir_constant_fold(rvalue))
       this->progress = true;
-   }
 }
 
 void