A64: Improve constraints on StoreKeyed instructions

src/a64/lithium-a64.cc

Index: src/a64/lithium-a64.cc
diff --git a/src/a64/lithium-a64.cc b/src/a64/lithium-a64.cc
index cf89c09f5b2515d2dbc0b6cabe667b10245eb9ea..38f9c731041430afd0955a52e42194d4e695fb5b 100644
--- a/src/a64/lithium-a64.cc
+++ b/src/a64/lithium-a64.cc
@@ -2169,7 +2169,7 @@ LInstruction* LChunkBuilder::DoStoreKeyed(HStoreKeyed* instr) {
   LOperand* temp = NULL;
   LOperand* elements = NULL;
   LOperand* val = NULL;
-  LOperand* key = NULL;
+  LOperand* key = UseRegisterOrConstantAtStart(instr->key());
 
   if (!instr->is_typed_elements() &&
       instr->value()->representation().IsTagged() &&
@@ -2177,11 +2177,11 @@ LInstruction* LChunkBuilder::DoStoreKeyed(HStoreKeyed* instr) {
     // RecordWrite() will clobber all registers.
     elements = UseRegisterAndClobber(instr->elements());
     val = UseRegisterAndClobber(instr->value());
-    key = UseRegisterAndClobber(instr->key());
+    temp = TempRegister();
   } else {
     elements = UseRegister(instr->elements());
     val = UseRegister(instr->value());
-    key = UseRegisterOrConstantAtStart(instr->key());
+    temp = instr->key()->IsConstant() ? NULL : TempRegister();
   }
 
   if (instr->is_typed_elements()) {
@@ -2193,23 +2193,16 @@ LInstruction* LChunkBuilder::DoStoreKeyed(HStoreKeyed* instr) {
             instr->elements()->representation().IsTagged()) ||
            (instr->is_external() &&
             instr->elements()->representation().IsExternal()));
-    temp = instr->key()->IsConstant() ? NULL : TempRegister();
     return new(zone()) LStoreKeyedExternal(elements, key, val, temp);
 
   } else if (instr->value()->representation().IsDouble()) {
     ASSERT(instr->elements()->representation().IsTagged());
-
-    // The constraint used here is UseRegister, even though the StoreKeyed
-    // instruction may canonicalize the value in the register if it is a NaN.
-    temp = TempRegister();
     return new(zone()) LStoreKeyedFixedDouble(elements, key, val, temp);
 
   } else {
     ASSERT(instr->elements()->representation().IsTagged());
     ASSERT(instr->value()->representation().IsSmiOrTagged() ||
            instr->value()->representation().IsInteger32());
-
-    temp = TempRegister();
     return new(zone()) LStoreKeyedFixed(elements, key, val, temp);
   }
 }