A64: UseRegisterAtStart for rhs of LMulS

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 12812bbf2e4f8b74928d0f56b4ad41b8981b670c..5d3d1eefda3e1459fd87b7ee341bff281ead037f 100644
--- a/src/a64/lithium-a64.cc
+++ b/src/a64/lithium-a64.cc
@@ -1849,8 +1849,7 @@ LInstruction* LChunkBuilder::DoMul(HMul* instr) {
     // allocated for the second operand.
     LInstruction* result;
     if (instr->representation().IsSmi()) {
-      // TODO(jbramley/rmcilroy): Fix LMulS so we can UseRegisterAtStart here.
-      LOperand* right = UseRegister(most_const);
+      LOperand* right = UseRegisterAtStart(most_const);
       result = DefineAsRegister(new(zone()) LMulS(left, right));
     } else {
       LOperand* right = UseRegisterAtStart(most_const);