ir_copy_propagation: New pass to rewrite dereferences to avoid copies.

This is pretty basic.  Right now it only handles pure assignments --
same type on each side, no swizzling, and only within basic blocks.

1 files changed, 6 insertions, 0 deletions

diff --git a/ir.h b/ir.h
index ce924206f8..d8568a8dae 100644
--- a/ir.h
+++ b/ir.h
@@ -62,6 +62,7 @@ public:
    virtual class ir_return *            as_return()           { return NULL; }
    virtual class ir_if *                as_if()               { return NULL; }
    virtual class ir_swizzle *           as_swizzle()          { return NULL; }
+   virtual class ir_constant *          as_constant()         { return NULL; }
    /*@}*/
 
 protected:
@@ -787,6 +788,11 @@ public:
    ir_constant(int i);
    ir_constant(float f);
 
+   virtual ir_constant *as_constant()
+   {
+      return this;
+   }
+
    virtual void accept(ir_visitor *v)
    {
       v->visit(this);