Remove partial.reduce.sub support

Author: NickGuy-Arm

llvm/lib/Target/AArch64/AArch64TargetTransformInfo.h

@@ -368,7 +368,7 @@ class AArch64TTIImpl : public BasicTTIImplBase<AArch64TTIImpl> {
     InstructionCost Invalid = InstructionCost::getInvalid();
     InstructionCost Cost(TTI::TCC_Basic);
 
-    if (Opcode != Instruction::Add && Opcode != Instruction::Sub)
+    if (Opcode != Instruction::Add)
       return Invalid;
 
     if (InputTypeA != InputTypeB)

llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp

@@ -317,22 +317,13 @@ void VPPartialReductionRecipe::execute(VPTransformState &State) {
   State.setDebugLocFrom(getDebugLoc());
   auto &Builder = State.Builder;
 
+  assert(getOpcode() == Instruction::Add &&
+         "Unhandled partial reduction opcode");
+
   Value *BinOpVal = State.get(getOperand(0));
   Value *PhiVal = State.get(getOperand(1));
   assert(PhiVal && BinOpVal && "Phi and Mul must be set");
 
-  auto Opcode = getOpcode();
-
-  // Currently we don't have a partial_reduce_sub intrinsic,
-  // so mimic the behaviour by negating the second operand
-  if (Opcode == Instruction::Sub) {
-    BinOpVal = Builder.CreateSub(Constant::getNullValue(BinOpVal->getType()),
-                                 BinOpVal);
-    Opcode = Instruction::Add;
-  }
-
-  assert(Opcode == Instruction::Add && "Unhandled partial reduction opcode");
-
   Type *RetTy = PhiVal->getType();
 
   CallInst *V = Builder.CreateIntrinsic(