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, 3 insertions, 0 deletions

diff --git a/ast.h b/ast.h
index a158910421..53b0e4a2b4 100644
--- a/ast.h
+++ b/ast.h
@@ -492,6 +492,9 @@ public:
 			   ast_node *else_statement);
    virtual void print(void) const;
 
+   virtual ir_rvalue *hir(exec_list *instructions,
+			  struct _mesa_glsl_parse_state *state);
+
    ast_expression *condition;
    ast_node *then_statement;
    ast_node *else_statement;