Fix performance regression in DXT5Decoder.js.

src/arm/lithium-arm.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 1941 matching lines @@
   LOperand* key = UseFixed(instr->key(), r0);
 
   LInstruction* result =
       DefineFixed(new(zone()) LLoadKeyedGeneric(object, key), r0);
   return MarkAsCall(result, instr);
 }
 
 
 LInstruction* LChunkBuilder::DoStoreKeyed(HStoreKeyed* instr) {
   ElementsKind elements_kind = instr->elements_kind();
-  bool needs_write_barrier = instr->NeedsWriteBarrier();
-  LOperand* key = needs_write_barrier
-      ? UseTempRegister(instr->key())
-      : UseRegisterOrConstantAtStart(instr->key());
+
+  if (!instr->is_external()) {
+    ASSERT(instr->elements()->representation().IsTagged());
+    bool needs_write_barrier = instr->NeedsWriteBarrier();
+    LOperand* object = NULL;
+    LOperand* key = NULL;
+    LOperand* val = NULL;
+
+    if (instr->value()->representation().IsDouble()) {
+      object = UseRegisterAtStart(instr->elements());
+      val = UseTempRegister(instr->value());
+      key = UseRegisterOrConstantAtStart(instr->key());
+    } else {
+      ASSERT(instr->value()->representation().IsTagged());
+      object = UseTempRegister(instr->elements());
+      val = needs_write_barrier ? UseTempRegister(instr->value())
+          : UseRegisterAtStart(instr->value());
+      key = needs_write_barrier ? UseTempRegister(instr->key())
+          : UseRegisterOrConstantAtStart(instr->key());
+    }
+
+    return new(zone()) LStoreKeyed(object, key, val);
+  }
+
+  ASSERT(
+      (instr->value()->representation().IsInteger32() &&
+       (elements_kind != EXTERNAL_FLOAT_ELEMENTS) &&
+       (elements_kind != EXTERNAL_DOUBLE_ELEMENTS)) ||
+      (instr->value()->representation().IsDouble() &&
+       ((elements_kind == EXTERNAL_FLOAT_ELEMENTS) ||
+        (elements_kind == EXTERNAL_DOUBLE_ELEMENTS))));
+  ASSERT(instr->elements()->representation().IsExternal());
   bool val_is_temp_register =
       elements_kind == EXTERNAL_PIXEL_ELEMENTS ||
       elements_kind == EXTERNAL_FLOAT_ELEMENTS;
-  LOperand* val = val_is_temp_register || needs_write_barrier
-      ? UseTempRegister(instr->value())
+  LOperand* val = val_is_temp_register ? UseTempRegister(instr->value())
       : UseRegister(instr->value());
-
-  LStoreKeyed* result = NULL;
-  if (!instr->is_external()) {
-    ASSERT(instr->elements()->representation().IsTagged());
-
-    LOperand* object = NULL;
-    if (instr->value()->representation().IsDouble()) {
-      object = UseRegisterAtStart(instr->elements());
-    } else {
-      ASSERT(instr->value()->representation().IsTagged());
-      object = UseTempRegister(instr->elements());
-    }
-
-    result = new(zone()) LStoreKeyed(object, key, val);
-  } else {
-    ASSERT(
-        (instr->value()->representation().IsInteger32() &&
-         (elements_kind != EXTERNAL_FLOAT_ELEMENTS) &&
-         (elements_kind != EXTERNAL_DOUBLE_ELEMENTS)) ||
-        (instr->value()->representation().IsDouble() &&
-         ((elements_kind == EXTERNAL_FLOAT_ELEMENTS) ||
-          (elements_kind == EXTERNAL_DOUBLE_ELEMENTS))));
-    ASSERT(instr->elements()->representation().IsExternal());
-
-    LOperand* external_pointer = UseRegister(instr->elements());
-    result = new(zone()) LStoreKeyed(external_pointer, key, val);
-  }
-
-  ASSERT(result != NULL);
-  return result;
+  LOperand* key = UseRegisterOrConstantAtStart(instr->key());
+  LOperand* external_pointer = UseRegister(instr->elements());
+  return new(zone()) LStoreKeyed(external_pointer, key, val);
 }
 
 
 LInstruction* LChunkBuilder::DoStoreKeyedGeneric(HStoreKeyedGeneric* instr) {
   LOperand* obj = UseFixed(instr->object(), r2);
   LOperand* key = UseFixed(instr->key(), r1);
   LOperand* val = UseFixed(instr->value(), r0);
 
   ASSERT(instr->object()->representation().IsTagged());
   ASSERT(instr->key()->representation().IsTagged());
@@ skipping 313 matching lines @@
 
 
 LInstruction* LChunkBuilder::DoLoadFieldByIndex(HLoadFieldByIndex* instr) {
   LOperand* object = UseRegister(instr->object());
   LOperand* index = UseRegister(instr->index());
   return DefineAsRegister(new(zone()) LLoadFieldByIndex(object, index));
 }
 
 
 } }  // namespace v8::internal