Implement ir_if (for if-statments) and conversion from AST

The following tests now pass:

    glslparsertest/shaders/if1.frag
    glslparsertest/shaders/if2.frag

The following tests that used to pass now fail.  It appears that most
of these fail because ast_nequal and ast_equal are not converted to HIR.

    shaders/glsl-unused-varying.frag
    shaders/glsl-fs-sqrt-branch.frag

1 files changed, 22 insertions, 0 deletions

diff --git a/ir.h b/ir.h
index 328cd4e4ff..83e4f95b0c 100644
--- a/ir.h
+++ b/ir.h
@@ -192,6 +192,28 @@ public:
 /*@}*/
 
 
+/**
+ * IR instruction representing high-level if-statements
+ */
+class ir_if : public ir_instruction {
+public:
+   ir_if(ir_rvalue *condition)
+      : condition(condition)
+   {
+      /* empty */
+   }
+
+   virtual void accept(ir_visitor *v)
+   {
+      v->visit(this);
+   }
+
+   ir_rvalue *condition;
+   exec_list  then_instructions;
+   exec_list  else_instructions;
+};
+
+
 class ir_assignment : public ir_rvalue {
 public:
    ir_assignment(ir_rvalue *lhs, ir_rvalue *rhs, ir_rvalue *condition);