MIPS: Port [turbofan] ARM64: Use zr for zeroing stack slots

src/compiler/mips64/code-generator-mips64.cc

Index: src/compiler/mips64/code-generator-mips64.cc
diff --git a/src/compiler/mips64/code-generator-mips64.cc b/src/compiler/mips64/code-generator-mips64.cc
index 6fef2884bef761169780a11f68d9780b8fa95fd3..7db7ce9b968ecae8b231ceb52f72ddcfbf4d0fbd 100644
--- a/src/compiler/mips64/code-generator-mips64.cc
+++ b/src/compiler/mips64/code-generator-mips64.cc
@@ -2385,9 +2385,14 @@ void CodeGenerator::AssembleMove(InstructionOperand* source,
     } else if (src.type() == Constant::kFloat32) {
       if (destination->IsFPStackSlot()) {
         MemOperand dst = g.ToMemOperand(destination);
-        __ li(at, Operand(bit_cast<int32_t>(src.ToFloat32())));
-        __ sw(at, dst);
+        if (bit_cast<int32_t>(src.ToFloat32()) == 0) {
+          __ sw(zero_reg, dst);
+        } else {
+          __ li(at, Operand(bit_cast<int32_t>(src.ToFloat32())));
+          __ sw(at, dst);
+        }
       } else {
+        DCHECK(destination->IsFPRegister());
         FloatRegister dst = g.ToSingleRegister(destination);
         __ Move(dst, src.ToFloat32());
       }