[llvm-dev] How do I prevent DAGCombiner from combining ZExt/SExt(load) into LoadZExt?

[Tim Northover via llvm-dev]

Hi Zhang,

On Wed, 6 Jan 2021 at 03:51, Zhang via llvm-dev <llvm-dev at lists.llvm.org> wrote:
> In our toy ISA, we don't have a dedicated ZExtLoad instruction. However DAGCombiner tends to combine ZERO_EXTEND(LOAD) into a LoadZExt node which can't be trivially selected:

I think you control that with a call to
TargetLowering::setLoadExtAction in XYZTargetLowering.

Cheers.

Tim.