Relax register constraints for LMathSqrt.

src/ia32/lithium-codegen-ia32.cc

Index: src/ia32/lithium-codegen-ia32.cc
diff --git a/src/ia32/lithium-codegen-ia32.cc b/src/ia32/lithium-codegen-ia32.cc
index c85f1ca45aabc06d48e232a4b43dc7b82b7b18fc..9fd0ae532cc9d29931dbcd821297e8c3b2becbc5 100644
--- a/src/ia32/lithium-codegen-ia32.cc
+++ b/src/ia32/lithium-codegen-ia32.cc
@@ -3708,9 +3708,9 @@ void LCodeGen::DoMathRound(LMathRound* instr) {
 
 
 void LCodeGen::DoMathSqrt(LMathSqrt* instr) {
-  XMMRegister input_reg = ToDoubleRegister(instr->value());
-  ASSERT(ToDoubleRegister(instr->result()).is(input_reg));
-  __ sqrtsd(input_reg, input_reg);
+  Operand input = ToOperand(instr->value());
+  XMMRegister output = ToDoubleRegister(instr->result());
+  __ sqrtsd(output, input);
 }