Relax register constraints for LMathSqrt.

src/ia32/lithium-ia32.cc

Index: src/ia32/lithium-ia32.cc
diff --git a/src/ia32/lithium-ia32.cc b/src/ia32/lithium-ia32.cc
index 58290759987e45cc3fdff4e7f8a4ca99c04c115e..3ebceea66a4539296d626c98d3f8b9f48e2a8bac 100644
--- a/src/ia32/lithium-ia32.cc
+++ b/src/ia32/lithium-ia32.cc
@@ -1219,9 +1219,8 @@ LInstruction* LChunkBuilder::DoMathExp(HUnaryMathOperation* instr) {
 
 
 LInstruction* LChunkBuilder::DoMathSqrt(HUnaryMathOperation* instr) {
-  LOperand* input = UseRegisterAtStart(instr->value());
-  LMathSqrt* result = new(zone()) LMathSqrt(input);
-  return DefineSameAsFirst(result);
+  LOperand* input = UseAtStart(instr->value());
+  return DefineAsRegister(new(zone()) LMathSqrt(input));
 }