[turbofan] Add backend support for load/store float32 values.

src/compiler/arm64/code-generator-arm64.cc

Index: src/compiler/arm64/code-generator-arm64.cc
diff --git a/src/compiler/arm64/code-generator-arm64.cc b/src/compiler/arm64/code-generator-arm64.cc
index baacc854c0dde758833bfb2be8190f8fd99d9d73..edd023dc1838d8cf87af8c08b1cf1c9f15a0255a 100644
--- a/src/compiler/arm64/code-generator-arm64.cc
+++ b/src/compiler/arm64/code-generator-arm64.cc
@@ -426,6 +426,20 @@ void CodeGenerator::AssembleArchInstruction(Instruction* instr) {
     case kArm64Str:
       __ Str(i.InputRegister(2), i.MemoryOperand());
       break;
+    case kArm64LdrS: {
+      UseScratchRegisterScope scope(masm());
+      FPRegister scratch = scope.AcquireS();
+      __ Ldr(scratch, i.MemoryOperand());
+      __ Fcvt(i.OutputDoubleRegister(), scratch);
+      break;
+    }
+    case kArm64StrS: {
+      UseScratchRegisterScope scope(masm());
+      FPRegister scratch = scope.AcquireS();
+      __ Fcvt(scratch, i.InputDoubleRegister(2));
+      __ Str(scratch, i.MemoryOperand());
+      break;
+    }
     case kArm64LdrD:
       __ Ldr(i.OutputDoubleRegister(), i.MemoryOperand());
       break;