X64 Crankshaft: Add DoPower to lithium compiler on x64 platform.

src/x64/lithium-codegen-x64.cc

Index: src/x64/lithium-codegen-x64.cc
===================================================================
--- src/x64/lithium-codegen-x64.cc	(revision 6962)
+++ src/x64/lithium-codegen-x64.cc	(working copy)
@@ -2462,7 +2462,57 @@
 
 
 void LCodeGen::DoPower(LPower* instr) {
-  Abort("Unimplemented: %s", "DoPower");
+  LOperand* left = instr->InputAt(0);
+  DoubleRegister left_reg = ToDoubleRegister(left);

[Rico, 2011/02/28 19:18:34]

I don't think we use DoubleRegister anywhere else do we, normally we use
XMMRegister. I was not even aware that we had a typedef of this

+  LOperand* right = instr->InputAt(1);
+  DoubleRegister result_reg = ToDoubleRegister(instr->result());
+  Representation exponent_type = instr->hydrogen()->right()->representation();
+  if (exponent_type.IsDouble()) {
+    DoubleRegister right_reg = ToDoubleRegister(right);
+    __ PrepareCallCFunction(2);
+    // Move arguments to correct registers
+    __ movsd(xmm0, left_reg);
+    if (!right_reg.is(xmm1)) {

[Rico, 2011/02/28 19:18:34]

We know that right is in xmm2, you explicitly request that in lithium-x64

+      __ movsd(xmm1, right_reg);
+    }
+    __ CallCFunction(ExternalReference::power_double_double_function(), 4);
+  } else if (exponent_type.IsInteger32()) {
+    Register right_reg = ToRegister(right);
+    __ PrepareCallCFunction(2);
+    // Move arguments to correct registers: xmm0 and edi (not rdi).
+    __ movsd(xmm0, left_reg);
+    if (!right_reg.is(rdi)) {

[Rico, 2011/02/28 19:18:34]

We know that right is in rax, you explicitly request this in lithium-x64

+      __ movl(rdi, right_reg);
+    }
+     __ CallCFunction(ExternalReference::power_double_int_function(), 4);
+  } else {
+    ASSERT(exponent_type.IsTagged());
+    CpuFeatures::Scope scope(SSE2);
+    Register right_reg = ToRegister(right);
+
+    Label non_smi, call;
+    __ JumpIfNotSmi(right_reg, &non_smi);
+    __ SmiToInteger32(right_reg, right_reg);
+    __ cvtlsi2sd(result_reg, right_reg);
+    __ jmp(&call);
+
+    __ bind(&non_smi);
+    __ CmpObjectType(right_reg, HEAP_NUMBER_TYPE , kScratchRegister);
+    DeoptimizeIf(not_equal, instr->environment());
+    __ movsd(result_reg, FieldOperand(right_reg, HeapNumber::kValueOffset));
+
+    __ bind(&call);
+    __ PrepareCallCFunction(2);
+    // Move arguments to correct registers xmm0 and xmm1.
+    __ movsd(xmm0, left_reg);
+    if (!result_reg.is(xmm1)) {
+      __ movsd(xmm1, result_reg);
+    }
+    // Right argument is already in xmm1.
+    __ CallCFunction(ExternalReference::power_double_double_function(), 4);
+  }
+  // Return value is in xmm0.
+  __ movsd(result_reg, xmm0);
 }