Reland of [turbofan] ARM: Implement vswp and use in gap resolver

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

Index: src/compiler/arm/code-generator-arm.cc
diff --git a/src/compiler/arm/code-generator-arm.cc b/src/compiler/arm/code-generator-arm.cc
index 4fa615576dc6c980aae2583eb5a470218fed2a60..e9e6621d2cac745cf5d9512289495c93ed415b3a 100644
--- a/src/compiler/arm/code-generator-arm.cc
+++ b/src/compiler/arm/code-generator-arm.cc
@@ -1912,33 +1912,31 @@ void CodeGenerator::AssembleSwap(InstructionOperand* source,
     __ vstr(temp_1, src);
   } else if (source->IsFPRegister()) {
     LowDwVfpRegister temp = kScratchDoubleReg;
-      DwVfpRegister src = g.ToDoubleRegister(source);
-      if (destination->IsFPRegister()) {
-        DwVfpRegister dst = g.ToDoubleRegister(destination);
-        __ Move(temp, src);
-        __ Move(src, dst);
-        __ Move(dst, temp);
-      } else {
-        DCHECK(destination->IsFPStackSlot());
-        MemOperand dst = g.ToMemOperand(destination);
-        __ Move(temp, src);
-        __ vldr(src, dst);
-        __ vstr(temp, dst);
-      }
+    DwVfpRegister src = g.ToDoubleRegister(source);
+    if (destination->IsFPRegister()) {
+      DwVfpRegister dst = g.ToDoubleRegister(destination);
+      __ vswp(src, dst);
+    } else {
+      DCHECK(destination->IsFPStackSlot());
+      MemOperand dst = g.ToMemOperand(destination);
+      __ Move(temp, src);
+      __ vldr(src, dst);
+      __ vstr(temp, dst);
+    }
   } else if (source->IsFPStackSlot()) {
     DCHECK(destination->IsFPStackSlot());
     Register temp_0 = kScratchReg;
     LowDwVfpRegister temp_1 = kScratchDoubleReg;
     MemOperand src0 = g.ToMemOperand(source);
     MemOperand dst0 = g.ToMemOperand(destination);
-      MemOperand src1(src0.rn(), src0.offset() + kPointerSize);
-      MemOperand dst1(dst0.rn(), dst0.offset() + kPointerSize);
-      __ vldr(temp_1, dst0);  // Save destination in temp_1.
-      __ ldr(temp_0, src0);   // Then use temp_0 to copy source to destination.
-      __ str(temp_0, dst0);
-      __ ldr(temp_0, src1);
-      __ str(temp_0, dst1);
-      __ vstr(temp_1, src0);
+    MemOperand src1(src0.rn(), src0.offset() + kPointerSize);
+    MemOperand dst1(dst0.rn(), dst0.offset() + kPointerSize);
+    __ vldr(temp_1, dst0);  // Save destination in temp_1.
+    __ ldr(temp_0, src0);   // Then use temp_0 to copy source to destination.
+    __ str(temp_0, dst0);
+    __ ldr(temp_0, src1);
+    __ str(temp_0, dst1);
+    __ vstr(temp_1, src0);
   } else {
     // No other combinations are possible.
     UNREACHABLE();