[AArch64] Teach the costmodel about widening muls

[dmgreen]

Summary

A vector mul(sext, sext) or mul(zext, zext) will be code generated as a single smull or umull instruction. This most notably effects v2i64 multiplies, which are otherwise not legal and need to be expanded.

The oneuse check has also been slightly changed, as it is already checked from the use of isWideningInstruction in getCastInstrCost.

[SjoerdMeijer]

Looks like a good one to me.

llvm/lib/Target/AArch64/AArch64TargetTransformInfo.cpp

1292

While we are at it, look at shl in a follow up? :)

1839–1840

Nit: we don't need the brackets?

[dmgreen]

Thanks.

llvm/lib/Target/AArch64/AArch64TargetTransformInfo.cpp

1292

I'll see what I can do about this and any others. I think they are much rarer than mul, which can come up a fair amount.

1839–1840

Oh yeah, I will remove it.

llvm/lib/Target/AArch64/AArch64TargetTransformInfo.cpp

bool AArch64TTIImpl::isWideningInstruction(Type *DstTy, unsigned Opcode,
   // 16-bits wide.
   if (!DstTy->isVectorTy() || DstTy->getScalarSizeInBits() < 16)
     return false;
 
   // Determine if the operation has a widening variant. We consider both the
   // "long" (e.g., usubl) and "wide" (e.g., usubw) versions of the
   // instructions.
   //
-  // TODO: Add additional widening operations (e.g., mul, shl, etc.) once we
+  // TODO: Add additional widening operations (e.g., shl, etc.) once we
   //       verify that their extending operands are eliminated during code
   //       generation.
   switch (Opcode) {
   case Instruction::Add: // UADDL(2), SADDL(2), UADDW(2), SADDW(2).
   case Instruction::Sub: // USUBL(2), SSUBL(2), USUBW(2), SSUBW(2).
+  case Instruction::Mul: // SMULL(2), UMULL(2)
     break;
   default:
     return false;
   }
 
   // To be a widening instruction (either the "wide" or "long" versions), the
-  // second operand must be a sign- or zero extend having a single user. We
-  // only consider extends having a single user because they may otherwise not
-  // be eliminated.
+  // second operand must be a sign- or zero extend.
   if (Args.size() != 2 ||
-      (!isa<SExtInst>(Args[1]) && !isa<ZExtInst>(Args[1])) ||
-      !Args[1]->hasOneUse())
+      (!isa<SExtInst>(Args[1]) && !isa<ZExtInst>(Args[1])))
     return false;
   auto *Extend = cast<CastInst>(Args[1]);
+  auto *Arg0 = dyn_cast<CastInst>(Args[0]);
+
+  // A mul only has a mull version (not like addw). Both operands need to be
+  // extending and the same type.
+  if (Opcode == Instruction::Mul &&
+      (!Arg0 || Arg0->getOpcode() != Extend->getOpcode() ||
+       Arg0->getOperand(0)->getType() != Extend->getOperand(0)->getType()))
+    return false;
 
   // Legalize the destination type and ensure it can be used in a widening
   // operation.
   auto DstTyL = TLI->getTypeLegalizationCost(DL, DstTy);
   unsigned DstElTySize = DstTyL.second.getScalarSizeInBits();
   if (!DstTyL.second.isVector() || DstElTySize != DstTy->getScalarSizeInBits())
     return false;
 
InstructionCost AArch64TTIImpl::getCastInstrCost(unsigned Opcode, Type *Dst,
                                                  TTI::CastContextHint CCH,
                                                  TTI::TargetCostKind CostKind,
                                                  const Instruction *I) {
   int ISD = TLI->InstructionOpcodeToISD(Opcode);
   assert(ISD && "Invalid opcode");
 
   // If the cast is observable, and it is used by a widening instruction (e.g.,
   // uaddl, saddw, etc.), it may be free.
-  if (I && I->hasOneUse()) {
+  if (I && I->hasOneUser()) {
     auto *SingleUser = cast<Instruction>(*I->user_begin());
     SmallVector<const Value *, 4> Operands(SingleUser->operand_values());
     if (isWideningInstruction(Dst, SingleUser->getOpcode(), Operands)) {
       // If the cast is the second operand, it is free. We will generate either
       // a "wide" or "long" version of the widening instruction.
       if (I == SingleUser->getOperand(1))
         return 0;
       // If the cast is not the second operand, it will be free if it looks the
if (Ty->isVectorTy()) {
                                      Opd1Info, Opd2Info, Opd1PropInfo,
                                      Opd2PropInfo);
       // TODO: if one of the arguments is scalar, then it's not necessary to
       // double the cost of handling the vector elements.
       Cost += Cost;
     }
     return Cost;
   }
   case ISD::MUL:
-    if (LT.second != MVT::v2i64)
-      return LT.first;
     // Since we do not have a MUL.2d instruction, a mul <2 x i64> is expensive
     // as elements are extracted from the vectors and the muls scalarized.
     // As getScalarizationOverhead is a bit too pessimistic, we estimate the
     // cost for a i64 vector directly here, which is:
     // - four i64 extracts,
     // - two i64 inserts, and
     // - two muls.
     // So, for a v2i64 with LT.First = 1 the cost is 8, and for a v4i64 with
-    // LT.first = 2 the cost is 16.
+    // LT.first = 2 the cost is 16. If both operands are extensions it will not
+    // need to scalarize so the cost can be cheaper (smull or umull).
+    if (LT.second != MVT::v2i64 || isWideningInstruction(Ty, Opcode, Args))
+      return LT.first;
     return LT.first * 8;
   case ISD::ADD:
   case ISD::XOR:
   case ISD::OR:
   case ISD::AND:
   case ISD::SRL:
   case ISD::SRA:
   case ISD::SHL:

llvm/test/Analysis/CostModel/AArch64/arith-widening.ll

 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 8 for instruction: %asl_16_64 = mul <2 x i64> %sl1_16_64, %sl2_16_64
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %zw_16_64 = zext <2 x i16> %i16 to <2 x i64>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 8 for instruction: %azw_16_64 = mul <2 x i64> %i64, %zw_16_64
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %zl1_16_64 = zext <2 x i16> %i16 to <2 x i64>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %zl2_16_64 = zext <2 x i16> %i16 to <2 x i64>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 8 for instruction: %azl_16_64 = mul <2 x i64> %zl1_16_64, %zl2_16_64
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %sw_32_64 = sext <2 x i32> %i32 to <2 x i64>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 8 for instruction: %asw_32_64 = mul <2 x i64> %i64, %sw_32_64
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %sl1_32_64 = sext <2 x i32> %i32 to <2 x i64>
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %sl2_32_64 = sext <2 x i32> %i32 to <2 x i64>
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 8 for instruction: %asl_32_64 = mul <2 x i64> %sl1_32_64, %sl2_32_64
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %sl1_32_64 = sext <2 x i32> %i32 to <2 x i64>
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %sl2_32_64 = sext <2 x i32> %i32 to <2 x i64>
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %asl_32_64 = mul <2 x i64> %sl1_32_64, %sl2_32_64
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %zw_32_64 = zext <2 x i32> %i32 to <2 x i64>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 8 for instruction: %azw_32_64 = mul <2 x i64> %i64, %zw_32_64
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %zl1_32_64 = zext <2 x i32> %i32 to <2 x i64>
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %zl2_32_64 = zext <2 x i32> %i32 to <2 x i64>
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 8 for instruction: %azl_32_64 = mul <2 x i64> %zl1_32_64, %zl2_32_64
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %zl1_32_64 = zext <2 x i32> %i32 to <2 x i64>
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %zl2_32_64 = zext <2 x i32> %i32 to <2 x i64>
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %azl_32_64 = mul <2 x i64> %zl1_32_64, %zl2_32_64
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret void
 ;
   %sw_8_16 = sext <2 x i8> %i8 to <2 x i16>
   %asw_8_16 = mul <2 x i16> %i16, %sw_8_16
   %sl1_8_16 = sext <2 x i8> %i8 to <2 x i16>
   %sl2_8_16 = sext <2 x i8> %i8 to <2 x i16>
   %asl_8_16 = mul <2 x i16> %sl1_8_16, %sl2_8_16
 

 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 16 for instruction: %asl_8_64 = mul <4 x i64> %sl1_8_64, %sl2_8_64
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 3 for instruction: %zw_8_64 = zext <4 x i8> %i8 to <4 x i64>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 16 for instruction: %azw_8_64 = mul <4 x i64> %i64, %zw_8_64
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 3 for instruction: %zl1_8_64 = zext <4 x i8> %i8 to <4 x i64>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 3 for instruction: %zl2_8_64 = zext <4 x i8> %i8 to <4 x i64>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 16 for instruction: %azl_8_64 = mul <4 x i64> %zl1_8_64, %zl2_8_64
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %sw_16_32 = sext <4 x i16> %i16 to <4 x i32>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %asw_16_32 = mul <4 x i32> %i32, %sw_16_32
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %sl1_16_32 = sext <4 x i16> %i16 to <4 x i32>
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %sl2_16_32 = sext <4 x i16> %i16 to <4 x i32>
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %sl1_16_32 = sext <4 x i16> %i16 to <4 x i32>
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %sl2_16_32 = sext <4 x i16> %i16 to <4 x i32>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %asl_16_32 = mul <4 x i32> %sl1_16_32, %sl2_16_32
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %zw_16_32 = zext <4 x i16> %i16 to <4 x i32>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %azw_16_32 = mul <4 x i32> %i32, %zw_16_32
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %zl1_16_32 = zext <4 x i16> %i16 to <4 x i32>
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %zl2_16_32 = zext <4 x i16> %i16 to <4 x i32>
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %zl1_16_32 = zext <4 x i16> %i16 to <4 x i32>
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %zl2_16_32 = zext <4 x i16> %i16 to <4 x i32>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %azl_16_32 = mul <4 x i32> %zl1_16_32, %zl2_16_32
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 3 for instruction: %sw_16_64 = sext <4 x i16> %i16 to <4 x i64>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 16 for instruction: %asw_16_64 = mul <4 x i64> %i64, %sw_16_64
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 3 for instruction: %sl1_16_64 = sext <4 x i16> %i16 to <4 x i64>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 3 for instruction: %sl2_16_64 = sext <4 x i16> %i16 to <4 x i64>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 16 for instruction: %asl_16_64 = mul <4 x i64> %sl1_16_64, %sl2_16_64
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 3 for instruction: %zw_16_64 = zext <4 x i16> %i16 to <4 x i64>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 16 for instruction: %azw_16_64 = mul <4 x i64> %i64, %zw_16_64
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 3 for instruction: %zl1_16_64 = zext <4 x i16> %i16 to <4 x i64>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 3 for instruction: %zl2_16_64 = zext <4 x i16> %i16 to <4 x i64>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 16 for instruction: %azl_16_64 = mul <4 x i64> %zl1_16_64, %zl2_16_64
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %sw_32_64 = sext <4 x i32> %i32 to <4 x i64>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 16 for instruction: %asw_32_64 = mul <4 x i64> %i64, %sw_32_64
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %sl1_32_64 = sext <4 x i32> %i32 to <4 x i64>
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %sl2_32_64 = sext <4 x i32> %i32 to <4 x i64>
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 16 for instruction: %asl_32_64 = mul <4 x i64> %sl1_32_64, %sl2_32_64
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %sl1_32_64 = sext <4 x i32> %i32 to <4 x i64>
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %sl2_32_64 = sext <4 x i32> %i32 to <4 x i64>
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %asl_32_64 = mul <4 x i64> %sl1_32_64, %sl2_32_64
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %zw_32_64 = zext <4 x i32> %i32 to <4 x i64>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 16 for instruction: %azw_32_64 = mul <4 x i64> %i64, %zw_32_64
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %zl1_32_64 = zext <4 x i32> %i32 to <4 x i64>
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %zl2_32_64 = zext <4 x i32> %i32 to <4 x i64>
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 16 for instruction: %azl_32_64 = mul <4 x i64> %zl1_32_64, %zl2_32_64
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %zl1_32_64 = zext <4 x i32> %i32 to <4 x i64>
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %zl2_32_64 = zext <4 x i32> %i32 to <4 x i64>
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %azl_32_64 = mul <4 x i64> %zl1_32_64, %zl2_32_64
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret void
 ;
   %sw_8_16 = sext <4 x i8> %i8 to <4 x i16>
   %asw_8_16 = mul <4 x i16> %i16, %sw_8_16
   %sl1_8_16 = sext <4 x i8> %i8 to <4 x i16>
   %sl2_8_16 = sext <4 x i8> %i8 to <4 x i16>
   %asl_8_16 = mul <4 x i16> %sl1_8_16, %sl2_8_16
 
;
 
   ret void
 }
 
 define void @extmulv8(<8 x i8> %i8, <8 x i16> %i16, <8 x i32> %i32, <8 x i64> %i64)  {
 ; CHECK-LABEL: 'extmulv8'
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %sw_8_16 = sext <8 x i8> %i8 to <8 x i16>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %asw_8_16 = mul <8 x i16> %i16, %sw_8_16
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %sl1_8_16 = sext <8 x i8> %i8 to <8 x i16>
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %sl2_8_16 = sext <8 x i8> %i8 to <8 x i16>
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %sl1_8_16 = sext <8 x i8> %i8 to <8 x i16>
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %sl2_8_16 = sext <8 x i8> %i8 to <8 x i16>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %asl_8_16 = mul <8 x i16> %sl1_8_16, %sl2_8_16
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %zw_8_16 = zext <8 x i8> %i8 to <8 x i16>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %azw_8_16 = mul <8 x i16> %i16, %zw_8_16
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %zl1_8_16 = zext <8 x i8> %i8 to <8 x i16>
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %zl2_8_16 = zext <8 x i8> %i8 to <8 x i16>
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %zl1_8_16 = zext <8 x i8> %i8 to <8 x i16>
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %zl2_8_16 = zext <8 x i8> %i8 to <8 x i16>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %azl_8_16 = mul <8 x i16> %zl1_8_16, %zl2_8_16
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 3 for instruction: %sw_8_32 = sext <8 x i8> %i8 to <8 x i32>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %asw_8_32 = mul <8 x i32> %i32, %sw_8_32
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 3 for instruction: %sl1_8_32 = sext <8 x i8> %i8 to <8 x i32>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 3 for instruction: %sl2_8_32 = sext <8 x i8> %i8 to <8 x i32>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %asl_8_32 = mul <8 x i32> %sl1_8_32, %sl2_8_32
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 3 for instruction: %zw_8_32 = zext <8 x i8> %i8 to <8 x i32>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %azw_8_32 = mul <8 x i32> %i32, %zw_8_32
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 3 for instruction: %zl1_8_32 = zext <8 x i8> %i8 to <8 x i32>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 3 for instruction: %zl2_8_32 = zext <8 x i8> %i8 to <8 x i32>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %azl_8_32 = mul <8 x i32> %zl1_8_32, %zl2_8_32
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 7 for instruction: %sw_8_64 = sext <8 x i8> %i8 to <8 x i64>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 32 for instruction: %asw_8_64 = mul <8 x i64> %i64, %sw_8_64
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 7 for instruction: %sl1_8_64 = sext <8 x i8> %i8 to <8 x i64>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 7 for instruction: %sl2_8_64 = sext <8 x i8> %i8 to <8 x i64>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 32 for instruction: %asl_8_64 = mul <8 x i64> %sl1_8_64, %sl2_8_64
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 7 for instruction: %zw_8_64 = zext <8 x i8> %i8 to <8 x i64>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 32 for instruction: %azw_8_64 = mul <8 x i64> %i64, %zw_8_64
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 7 for instruction: %zl1_8_64 = zext <8 x i8> %i8 to <8 x i64>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 7 for instruction: %zl2_8_64 = zext <8 x i8> %i8 to <8 x i64>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 32 for instruction: %azl_8_64 = mul <8 x i64> %zl1_8_64, %zl2_8_64
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %sw_16_32 = sext <8 x i16> %i16 to <8 x i32>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %asw_16_32 = mul <8 x i32> %i32, %sw_16_32
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %sl1_16_32 = sext <8 x i16> %i16 to <8 x i32>
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %sl2_16_32 = sext <8 x i16> %i16 to <8 x i32>
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %sl1_16_32 = sext <8 x i16> %i16 to <8 x i32>
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %sl2_16_32 = sext <8 x i16> %i16 to <8 x i32>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %asl_16_32 = mul <8 x i32> %sl1_16_32, %sl2_16_32
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %zw_16_32 = zext <8 x i16> %i16 to <8 x i32>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %azw_16_32 = mul <8 x i32> %i32, %zw_16_32
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %zl1_16_32 = zext <8 x i16> %i16 to <8 x i32>
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %zl2_16_32 = zext <8 x i16> %i16 to <8 x i32>
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %zl1_16_32 = zext <8 x i16> %i16 to <8 x i32>
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %zl2_16_32 = zext <8 x i16> %i16 to <8 x i32>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %azl_16_32 = mul <8 x i32> %zl1_16_32, %zl2_16_32
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 6 for instruction: %sw_16_64 = sext <8 x i16> %i16 to <8 x i64>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 32 for instruction: %asw_16_64 = mul <8 x i64> %i64, %sw_16_64
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 6 for instruction: %sl1_16_64 = sext <8 x i16> %i16 to <8 x i64>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 6 for instruction: %sl2_16_64 = sext <8 x i16> %i16 to <8 x i64>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 32 for instruction: %asl_16_64 = mul <8 x i64> %sl1_16_64, %sl2_16_64
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 6 for instruction: %zw_16_64 = zext <8 x i16> %i16 to <8 x i64>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 32 for instruction: %azw_16_64 = mul <8 x i64> %i64, %zw_16_64
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 6 for instruction: %zl1_16_64 = zext <8 x i16> %i16 to <8 x i64>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 6 for instruction: %zl2_16_64 = zext <8 x i16> %i16 to <8 x i64>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 32 for instruction: %azl_16_64 = mul <8 x i64> %zl1_16_64, %zl2_16_64
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %sw_32_64 = sext <8 x i32> %i32 to <8 x i64>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 32 for instruction: %asw_32_64 = mul <8 x i64> %i64, %sw_32_64
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %sl1_32_64 = sext <8 x i32> %i32 to <8 x i64>
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %sl2_32_64 = sext <8 x i32> %i32 to <8 x i64>
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 32 for instruction: %asl_32_64 = mul <8 x i64> %sl1_32_64, %sl2_32_64
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %sl1_32_64 = sext <8 x i32> %i32 to <8 x i64>
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %sl2_32_64 = sext <8 x i32> %i32 to <8 x i64>
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %asl_32_64 = mul <8 x i64> %sl1_32_64, %sl2_32_64
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %zw_32_64 = zext <8 x i32> %i32 to <8 x i64>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 32 for instruction: %azw_32_64 = mul <8 x i64> %i64, %zw_32_64
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %zl1_32_64 = zext <8 x i32> %i32 to <8 x i64>
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %zl2_32_64 = zext <8 x i32> %i32 to <8 x i64>
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 32 for instruction: %azl_32_64 = mul <8 x i64> %zl1_32_64, %zl2_32_64
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %zl1_32_64 = zext <8 x i32> %i32 to <8 x i64>
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %zl2_32_64 = zext <8 x i32> %i32 to <8 x i64>
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %azl_32_64 = mul <8 x i64> %zl1_32_64, %zl2_32_64
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret void
 ;
   %sw_8_16 = sext <8 x i8> %i8 to <8 x i16>
   %asw_8_16 = mul <8 x i16> %i16, %sw_8_16
   %sl1_8_16 = sext <8 x i8> %i8 to <8 x i16>
   %sl2_8_16 = sext <8 x i8> %i8 to <8 x i16>
   %asl_8_16 = mul <8 x i16> %sl1_8_16, %sl2_8_16
 
;
 
   ret void
 }
 
 define void @extmulv16(<16 x i8> %i8, <16 x i16> %i16, <16 x i32> %i32, <16 x i64> %i64)  {
 ; CHECK-LABEL: 'extmulv16'
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %sw_8_16 = sext <16 x i8> %i8 to <16 x i16>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %asw_8_16 = mul <16 x i16> %i16, %sw_8_16
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %sl1_8_16 = sext <16 x i8> %i8 to <16 x i16>
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %sl2_8_16 = sext <16 x i8> %i8 to <16 x i16>
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %sl1_8_16 = sext <16 x i8> %i8 to <16 x i16>
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %sl2_8_16 = sext <16 x i8> %i8 to <16 x i16>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %asl_8_16 = mul <16 x i16> %sl1_8_16, %sl2_8_16
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %zw_8_16 = zext <16 x i8> %i8 to <16 x i16>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %azw_8_16 = mul <16 x i16> %i16, %zw_8_16
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %zl1_8_16 = zext <16 x i8> %i8 to <16 x i16>
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %zl2_8_16 = zext <16 x i8> %i8 to <16 x i16>
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %zl1_8_16 = zext <16 x i8> %i8 to <16 x i16>
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %zl2_8_16 = zext <16 x i8> %i8 to <16 x i16>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %azl_8_16 = mul <16 x i16> %zl1_8_16, %zl2_8_16
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 6 for instruction: %sw_8_32 = sext <16 x i8> %i8 to <16 x i32>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %asw_8_32 = mul <16 x i32> %i32, %sw_8_32
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 6 for instruction: %sl1_8_32 = sext <16 x i8> %i8 to <16 x i32>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 6 for instruction: %sl2_8_32 = sext <16 x i8> %i8 to <16 x i32>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %asl_8_32 = mul <16 x i32> %sl1_8_32, %sl2_8_32
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 6 for instruction: %zw_8_32 = zext <16 x i8> %i8 to <16 x i32>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %azw_8_32 = mul <16 x i32> %i32, %zw_8_32
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 6 for instruction: %zl1_8_32 = zext <16 x i8> %i8 to <16 x i32>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 6 for instruction: %zl2_8_32 = zext <16 x i8> %i8 to <16 x i32>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %azl_8_32 = mul <16 x i32> %zl1_8_32, %zl2_8_32
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 15 for instruction: %sw_8_64 = sext <16 x i8> %i8 to <16 x i64>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 64 for instruction: %asw_8_64 = mul <16 x i64> %i64, %sw_8_64
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 15 for instruction: %sl1_8_64 = sext <16 x i8> %i8 to <16 x i64>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 15 for instruction: %sl2_8_64 = sext <16 x i8> %i8 to <16 x i64>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 64 for instruction: %asl_8_64 = mul <16 x i64> %sl1_8_64, %sl2_8_64
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 15 for instruction: %zw_8_64 = zext <16 x i8> %i8 to <16 x i64>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 64 for instruction: %azw_8_64 = mul <16 x i64> %i64, %zw_8_64
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 15 for instruction: %zl1_8_64 = zext <16 x i8> %i8 to <16 x i64>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 15 for instruction: %zl2_8_64 = zext <16 x i8> %i8 to <16 x i64>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 64 for instruction: %azl_8_64 = mul <16 x i64> %zl1_8_64, %zl2_8_64
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %sw_16_32 = sext <16 x i16> %i16 to <16 x i32>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %asw_16_32 = mul <16 x i32> %i32, %sw_16_32
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %sl1_16_32 = sext <16 x i16> %i16 to <16 x i32>
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %sl2_16_32 = sext <16 x i16> %i16 to <16 x i32>
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %sl1_16_32 = sext <16 x i16> %i16 to <16 x i32>
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %sl2_16_32 = sext <16 x i16> %i16 to <16 x i32>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %asl_16_32 = mul <16 x i32> %sl1_16_32, %sl2_16_32
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %zw_16_32 = zext <16 x i16> %i16 to <16 x i32>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %azw_16_32 = mul <16 x i32> %i32, %zw_16_32
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %zl1_16_32 = zext <16 x i16> %i16 to <16 x i32>
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %zl2_16_32 = zext <16 x i16> %i16 to <16 x i32>
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %zl1_16_32 = zext <16 x i16> %i16 to <16 x i32>
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %zl2_16_32 = zext <16 x i16> %i16 to <16 x i32>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %azl_16_32 = mul <16 x i32> %zl1_16_32, %zl2_16_32
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 12 for instruction: %sw_16_64 = sext <16 x i16> %i16 to <16 x i64>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 64 for instruction: %asw_16_64 = mul <16 x i64> %i64, %sw_16_64
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 12 for instruction: %sl1_16_64 = sext <16 x i16> %i16 to <16 x i64>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 12 for instruction: %sl2_16_64 = sext <16 x i16> %i16 to <16 x i64>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 64 for instruction: %asl_16_64 = mul <16 x i64> %sl1_16_64, %sl2_16_64
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 12 for instruction: %zw_16_64 = zext <16 x i16> %i16 to <16 x i64>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 64 for instruction: %azw_16_64 = mul <16 x i64> %i64, %zw_16_64
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 12 for instruction: %zl1_16_64 = zext <16 x i16> %i16 to <16 x i64>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 12 for instruction: %zl2_16_64 = zext <16 x i16> %i16 to <16 x i64>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 64 for instruction: %azl_16_64 = mul <16 x i64> %zl1_16_64, %zl2_16_64
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 8 for instruction: %sw_32_64 = sext <16 x i32> %i32 to <16 x i64>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 64 for instruction: %asw_32_64 = mul <16 x i64> %i64, %sw_32_64
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 8 for instruction: %sl1_32_64 = sext <16 x i32> %i32 to <16 x i64>
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 8 for instruction: %sl2_32_64 = sext <16 x i32> %i32 to <16 x i64>
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 64 for instruction: %asl_32_64 = mul <16 x i64> %sl1_32_64, %sl2_32_64
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %sl1_32_64 = sext <16 x i32> %i32 to <16 x i64>
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %sl2_32_64 = sext <16 x i32> %i32 to <16 x i64>
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 8 for instruction: %asl_32_64 = mul <16 x i64> %sl1_32_64, %sl2_32_64
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 8 for instruction: %zw_32_64 = zext <16 x i32> %i32 to <16 x i64>
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 64 for instruction: %azw_32_64 = mul <16 x i64> %i64, %zw_32_64
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 8 for instruction: %zl1_32_64 = zext <16 x i32> %i32 to <16 x i64>
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 8 for instruction: %zl2_32_64 = zext <16 x i32> %i32 to <16 x i64>
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 64 for instruction: %azl_32_64 = mul <16 x i64> %zl1_32_64, %zl2_32_64
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %zl1_32_64 = zext <16 x i32> %i32 to <16 x i64>
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %zl2_32_64 = zext <16 x i32> %i32 to <16 x i64>
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 8 for instruction: %azl_32_64 = mul <16 x i64> %zl1_32_64, %zl2_32_64
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret void
 ;
   %sw_8_16 = sext <16 x i8> %i8 to <16 x i16>
   %asw_8_16 = mul <16 x i16> %i16, %sw_8_16
   %sl1_8_16 = sext <16 x i8> %i8 to <16 x i16>
   %sl2_8_16 = sext <16 x i8> %i8 to <16 x i16>
   %asl_8_16 = mul <16 x i16> %sl1_8_16, %sl2_8_16