[ARM] Add Neon saturating add and subtract instructions.

src/arm/assembler-arm.cc

Index: src/arm/assembler-arm.cc
diff --git a/src/arm/assembler-arm.cc b/src/arm/assembler-arm.cc
index 52213b06ccebc89d64b34939a0ebb730571f6828..ec75b7d07e62b2cb103761ede5e4253d3090b7d7 100644
--- a/src/arm/assembler-arm.cc
+++ b/src/arm/assembler-arm.cc
@@ -4272,7 +4272,19 @@ static Instr EncodeNeonBinOp(FPBinOp op, QwNeonRegister dst,
          vm | op_encoding;
 }
 
-enum IntegerBinOp { VADD, VSUB, VMUL, VMIN, VMAX, VTST, VCEQ, VCGE, VCGT };
+enum IntegerBinOp {
+  VADD,
+  VQADD,
+  VSUB,
+  VQSUB,
+  VMUL,
+  VMIN,
+  VMAX,
+  VTST,
+  VCEQ,
+  VCGE,
+  VCGT
+};
 
 static Instr EncodeNeonBinOp(IntegerBinOp op, NeonDataType dt,
                              const QwNeonRegister dst,
@@ -4283,9 +4295,15 @@ static Instr EncodeNeonBinOp(IntegerBinOp op, NeonDataType dt,
     case VADD:
       op_encoding = 0x8 * B8;
       break;
+    case VQADD:
+      op_encoding = B4;
+      break;
     case VSUB:
       op_encoding = B24 | 0x8 * B8;
       break;
+    case VQSUB:
+      op_encoding = 0x2 * B8 | B4;
+      break;
     case VMUL:
       op_encoding = 0x9 * B8 | B4;
       break;
@@ -4348,6 +4366,14 @@ void Assembler::vadd(NeonSize size, QwNeonRegister dst, QwNeonRegister src1,
   emit(EncodeNeonBinOp(VADD, size, dst, src1, src2));
 }
 
+void Assembler::vqadd(NeonDataType dt, QwNeonRegister dst, QwNeonRegister src1,
+                      QwNeonRegister src2) {
+  DCHECK(IsEnabled(NEON));
+  // Qd = vqadd(Qn, Qm) SIMD integer saturating addition.
+  // Instruction details available in ARM DDI 0406C.b, A8-996.
+  emit(EncodeNeonBinOp(VQADD, dt, dst, src1, src2));
+}
+
 void Assembler::vsub(QwNeonRegister dst, QwNeonRegister src1,
                      QwNeonRegister src2) {
   DCHECK(IsEnabled(NEON));
@@ -4364,6 +4390,14 @@ void Assembler::vsub(NeonSize size, QwNeonRegister dst, QwNeonRegister src1,
   emit(EncodeNeonBinOp(VSUB, size, dst, src1, src2));
 }
 
+void Assembler::vqsub(NeonDataType dt, QwNeonRegister dst, QwNeonRegister src1,
+                      QwNeonRegister src2) {
+  DCHECK(IsEnabled(NEON));
+  // Qd = vqsub(Qn, Qm) SIMD integer saturating subtraction.
+  // Instruction details available in ARM DDI 0406C.b, A8-1020.
+  emit(EncodeNeonBinOp(VQSUB, dt, dst, src1, src2));
+}
+
 void Assembler::vmul(QwNeonRegister dst, QwNeonRegister src1,
                      QwNeonRegister src2) {
   DCHECK(IsEnabled(NEON));