Missed transform: `umin/umax/smin/smax` on `i1` to `and/or`

[Kmeakin]

umin(i1, i1) => and: https://alive2.llvm.org/ce/z/tRp7VK
umax(i1, i1) => or: https://alive2.llvm.org/ce/z/7nS6Wp

smin(i1, i1) => or: https://alive2.llvm.org/ce/z/XXfBSk
smax(i1, i1) => and: https://alive2.llvm.org/ce/z/N9fqT2

[llvmbot]

Hi!

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[elhewaty]

Hi there,
I am a total beginner in LLVM although I have a solid knowledge of compilers, and I contributed to GCC, and SpiderMonkey before.
I really want to solve this, but can anyone please give me a hint about where to start?
Where in the source should I find this? or any information that can help?

[RKSimon]

I'd expect it'd probably get added inside InstCombinerImpl::visitCallInst for the smin/smax/umin/umax case:

llvm-project/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp

Line 1599 in 479955a

case Intrinsic::smin: {

A example of the fold for add (i1, i1) -> xor (i1, i1) can be found here:

llvm-project/llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp

Line 1426 in 479955a

return BinaryOperator::CreateXor(LHS, RHS);

[elhewaty]

@RKSimon I think I fixed it, how can I test the changes?
how can I know where make check-llvm fails exactly?

[RKSimon]

Try make check-llvm-transforms - but its likely you will need to add additional tests inside llvm-project/llvm/test/Transforms/InstCombine/

[RKSimon]

@elhewaty Any luck with adding test coverage?

[overlorde]

hi @elhewaty any update of the patch?

[Qi-Hu]

Hi @elhewaty, are you still working on this issue? If you don't mind, I'd like to take over. I wrote this patch as a practice: https://reviews.llvm.org/D158915.

[Qi-Hu]

The patch has been landed: 1a65cd3fcf58. This issue can be closed.