Changeset 41474 in webkit for trunk/JavaScriptCore/jit/JIT.cpp

Timestamp:

Mar 5, 2009, 11:02:10 PM (16 years ago)

Author:

[email protected]

Message:

2009-03-05 Gavin Barraclough <​[email protected]>

Reviewed by Oliver Hunt.

Writes of constant values to SF registers should be made with direct memory
writes where possible, rather than moving the value via a hardware register.

~3% win on SunSpider tests on x86, ~1.5% win on v8 tests on x86-64.

• assembler/MacroAssemblerX86_64.h: (JSC::MacroAssemblerX86_64::storePtr):
• assembler/X86Assembler.h: (JSC::X86Assembler::movq_i32m):
• jit/JIT.cpp: (JSC::JIT::privateCompileMainPass):

File:

• trunk/JavaScriptCore/jit/JIT.cpp (modified) (1 diff)

trunk/JavaScriptCore/jit/JIT.cpp

@@ -305 +305 @@
         switch (opcodeID) {
         case op_mov: {
-            emitGetVirtualRegister(currentInstruction[2].u.operand, regT0);
-            emitPutVirtualRegister(currentInstruction[1].u.operand);
+            int src = currentInstruction[2].u.operand;
+            int dst = currentInstruction[1].u.operand;
+
+            if (m_codeBlock->isConstantRegisterIndex(src)) {
+                storePtr(ImmPtr(JSValuePtr::encode(getConstantOperand(src))), Address(callFrameRegister, dst * sizeof(Register)));
+                if (dst == m_lastResultBytecodeRegister)
+                    killLastResultRegister();
+            } else {
+                emitGetVirtualRegister(src, regT0);
+                emitPutVirtualRegister(dst);
+            }
             NEXT_OPCODE(op_mov);
         }