[PATCH] D135991: [AArch64] Fix cost model for `udiv` instruction when one of the operands is a uniform constant

[Dave Green via Phabricator via llvm-commits]

dmgreen added inline comments.


================
Comment at: llvm/lib/Target/AArch64/AArch64TargetTransformInfo.cpp:2117
+            InstructionCost DivCost = BaseT::getArithmeticInstrCost(
+                Instruction::UDiv, Ty->getScalarType(), CostKind, Op1Info,
+                Op2Info);
----------------
zjaffal wrote:
> dmgreen wrote:
> > Should UDiv be Opcode, to handle SDiv a little better?
> Do you mean using `ISD::UDiv` instead of `Instruction::UDiv`. 
> I tried that but it get the following error if I do that 
> ```
> Assertion failed: (ISD && "Invalid opcode"), function getArithmeticInstrCost, file BasicTTIImpl.h, line 834.
> ```
> We can do the following instead 
> ```
> int Opcdoe = (ISD == ISD::UDIV) ? Instruction::UDiv : Instruction::SDiv;
> ```
I just meant the variable/argument `Opcode` - as far as I understand it could be UDiv or SDiv here.


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  https://reviews.llvm.org/D135991/new/

https://reviews.llvm.org/D135991