Revert "Added constant propagation and better variable liveness tracking to"

This reverts commit f54b07121f81a56145fb118a2e18841fc135717d.

Reason for revert: ASAN failure

Original change's description:
> Added constant propagation and better variable liveness tracking to
> skslc. 
> 
> This allows skslc to track the values of variables with constant
> values across multiple statements and replace variable references with
> constant values where appropriate.
> 
> The improved liveness tracking allows skslc to realize that a
> variable is no longer alive if all references to it have been
> replaced. It is not yet doing much with this information; better
> dead code elimination is coming in a followup change.
> 
> BUG=skia:
> 
> Change-Id: I6bf267d478b769caf0063ac3597dc16bbe618cb4
> Reviewed-on: https://skia-review.googlesource.com/7033
> Commit-Queue: Ethan Nicholas <ethannicholas@google.com>
> Reviewed-by: Greg Daniel <egdaniel@google.com>
> 

TBR=egdaniel@google.com,ethannicholas@google.com
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=skia:

Change-Id: Id2e26bce96b27df73948f8b32d3dff2e358ae0d6
Reviewed-on: https://skia-review.googlesource.com/7274
Commit-Queue: Ethan Nicholas <ethannicholas@google.com>
Reviewed-by: Ethan Nicholas <ethannicholas@google.com>

1 files changed, 4 insertions, 14 deletions

diff --git a/src/sksl/ir/SkSLBinaryExpression.h b/src/sksl/ir/SkSLBinaryExpression.h
index de85e4812b..132513e7f7 100644
--- a/src/sksl/ir/SkSLBinaryExpression.h
+++ b/src/sksl/ir/SkSLBinaryExpression.h
@@ -4,19 +4,17 @@
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
-
+ 
 #ifndef SKSL_BINARYEXPRESSION
 #define SKSL_BINARYEXPRESSION
 
 #include "SkSLExpression.h"
-#include "SkSLExpression.h"
-#include "../SkSLIRGenerator.h"
 #include "../SkSLToken.h"
 
 namespace SkSL {
 
 /**
- * A binary operation.
+ * A binary operation. 
  */
 struct BinaryExpression : public Expression {
     BinaryExpression(Position position, std::unique_ptr<Expression> left, Token::Kind op,
@@ -26,22 +24,14 @@ struct BinaryExpression : public Expression {
     , fOperator(op)
     , fRight(std::move(right)) {}
 
-    virtual std::unique_ptr<Expression> constantPropagate(
-                                                        const IRGenerator& irGenerator,
-                                                        const DefinitionMap& definitions) override {
-        return irGenerator.constantFold(*fLeft,
-                                        fOperator,
-                                        *fRight);
-    }
-
     virtual SkString description() const override {
         return "(" + fLeft->description() + " " + Token::OperatorName(fOperator) + " " +
                fRight->description() + ")";
     }
 
-    std::unique_ptr<Expression> fLeft;
+    const std::unique_ptr<Expression> fLeft;
     const Token::Kind fOperator;
-    std::unique_ptr<Expression> fRight;
+    const std::unique_ptr<Expression> fRight;
 
     typedef Expression INHERITED;
 };