[stubs] Suppress shifts with immediate shift of zero.

src/compiler/code-assembler.cc

Index: src/compiler/code-assembler.cc
diff --git a/src/compiler/code-assembler.cc b/src/compiler/code-assembler.cc
index 46208751cd7bbdc2bf5a26833a4d44ecae9abcf5..3ef8243a50865a4fde987a413f306c5452c24665 100644
--- a/src/compiler/code-assembler.cc
+++ b/src/compiler/code-assembler.cc
@@ -209,11 +209,18 @@ CODE_ASSEMBLER_BINARY_OP_LIST(DEFINE_CODE_ASSEMBLER_BINARY_OP)
 #undef DEFINE_CODE_ASSEMBLER_BINARY_OP
 
 Node* CodeAssembler::WordShl(Node* value, int shift) {
-  return raw_assembler_->WordShl(value, IntPtrConstant(shift));
+  return (shift != 0) ? raw_assembler_->WordShl(value, IntPtrConstant(shift))
+                      : value;
 }
 
 Node* CodeAssembler::WordShr(Node* value, int shift) {
-  return raw_assembler_->WordShr(value, IntPtrConstant(shift));
+  return (shift != 0) ? raw_assembler_->WordShr(value, IntPtrConstant(shift))
+                      : value;
+}
+
+Node* CodeAssembler::Word32Shr(Node* value, int shift) {
+  return (shift != 0) ? raw_assembler_->Word32Shr(value, IntPtrConstant(shift))
+                      : value;
 }
 
 Node* CodeAssembler::ChangeUint32ToWord(Node* value) {