Fix performance regression in DXT5Decoder.js.

src/x64/lithium-x64.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 1867 matching lines @@
   LOperand* object = UseFixed(instr->object(), rdx);
   LOperand* key = UseFixed(instr->key(), rax);
 
   LLoadKeyedGeneric* result = new(zone()) LLoadKeyedGeneric(object, key);
   return MarkAsCall(DefineFixed(result, rax), instr);
 }
 
 
 LInstruction* LChunkBuilder::DoStoreKeyed(HStoreKeyed* instr) {
   ElementsKind elements_kind = instr->elements_kind();
-  bool needs_write_barrier = instr->NeedsWriteBarrier();
   bool clobbers_key = instr->key()->representation().IsTagged();
-  LOperand* key = (clobbers_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 = clobbers_key ? UseTempRegister(instr->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 = (clobbers_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 = (needs_write_barrier || val_is_temp_register)
-      ? UseTempRegister(instr->value())
-      : UseRegisterAtStart(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* val = val_is_temp_register ? UseTempRegister(instr->value())
+      : UseRegister(instr->value());
+  LOperand* key = clobbers_key ? UseTempRegister(instr->key())
+      : UseRegisterOrConstantAtStart(instr->key());
+  LOperand* external_pointer = UseRegister(instr->elements());
+  return new(zone()) LStoreKeyed(external_pointer, key, val);
 }
 
 
 LInstruction* LChunkBuilder::DoStoreKeyedGeneric(HStoreKeyedGeneric* instr) {
   LOperand* object = UseFixed(instr->object(), rdx);
   LOperand* key = UseFixed(instr->key(), rcx);
   LOperand* value = UseFixed(instr->value(), rax);
 
   ASSERT(instr->object()->representation().IsTagged());
   ASSERT(instr->key()->representation().IsTagged());
@@ skipping 320 matching lines @@
 LInstruction* LChunkBuilder::DoLoadFieldByIndex(HLoadFieldByIndex* instr) {
   LOperand* object = UseRegister(instr->object());
   LOperand* index = UseTempRegister(instr->index());
   return DefineSameAsFirst(new(zone()) LLoadFieldByIndex(object, index));
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64