[llvm] [SLP] Make getSameOpcode support interchangeable instructions. (PR #127450)

[Han-Kuan Chen via llvm-commits]

HanKuanChen wrote:

> This commit causes a crash when building highway tests, e.g. https://github.com/google/highway/blob/master/hwy/tests/arithmetic_test.cc
> 
> Some tests (e.g. [unroller_test.cc](https://github.com/google/highway/blob/master/hwy/tests/unroller_test.cc)) fail with an assertion:
> 
> ```
> assert.h assertion failed at llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp:18508 in void llvm::slpvectorizer::BoUpSLP::BlockScheduling::cancelScheduling(ArrayRef<Value *>, Value *): Bundle->isSchedulingEntity() && (Bundle->isPartOfBundle() || needToScheduleSingleInstruction(VL)) && "tried to unbundle something which is not a bundle"
> *** Check failure stack trace: ***
>     @     0x555d3e1577b0  llvm::slpvectorizer::BoUpSLP::BlockScheduling::cancelScheduling()
>     @     0x555d3e11d390  llvm::slpvectorizer::BoUpSLP::BlockScheduling::tryScheduleBundle()
>     @     0x555d3e1107f8  llvm::slpvectorizer::BoUpSLP::buildTree_rec()
>     @     0x555d3e11259f  llvm::slpvectorizer::BoUpSLP::buildTree_rec()
>     @     0x555d3e111620  llvm::slpvectorizer::BoUpSLP::buildTree_rec()
>     @     0x555d3e167823  llvm::SLPVectorizerPass::tryToVectorizeList()
>     @     0x555d3e168afa  llvm::SLPVectorizerPass::tryToVectorize()
>     @     0x555d3e16ba81  llvm::SLPVectorizerPass::vectorizeRootInstruction()
>     @     0x555d3e16146f  llvm::SLPVectorizerPass::vectorizeChainsInBlock()
>     @     0x555d3e15e54e  llvm::SLPVectorizerPass::runImpl()
>     @     0x555d3e15dc5c  llvm::SLPVectorizerPass::run()
> ...
> 3.	Running pass "function<eager-inv>(float2int,lower-constant-intrinsics,chr,loop(loop-rotate<header-duplication;no-prepare-for-lto>,loop-deletion),loop-distribute,inject-tli-mappings,loop-vectorize<no-interleave-forced-only;no-vectorize-forced-only;>,infer-alignment,loop-load-elim,instcombine<max-iterations=1;no-verify-fixpoint>,simplifycfg<bonus-inst-threshold=1;forward-switch-cond;switch-range-to-icmp;switch-to-lookup;no-keep-loops;hoist-common-insts;no-hoist-loads-stores-with-cond-faulting;sink-common-insts;speculate-blocks;simplify-cond-branch;no-speculate-unpredictables>,slp-vectorizer,vector-combine,instcombine<max-iterations=1;no-verify-fixpoint>,loop-unroll<O3>,transform-warning,sroa<preserve-cfg>,infer-alignment,instcombine<max-iterations=1;no-verify-fixpoint>,loop-mssa(licm<allowspeculation>),alignment-from-assumptions,loop-sink,instsimplify,div-rem-pairs,tailcallelim,simplifycfg<bonus-inst-threshold=1;no-forward-switch-cond;switch-range-to-icmp;no-switch-to-lookup;keep-loops;no-hoist-common-insts;hoist-loads-stores-with-cond-faulting;no-sink-common-insts;speculate-blocks;simplify-cond-branch;speculate-unpredictables>)" on module "hwy/contrib/unroller/unroller_test.cc"
> ```
> 
> Other tests (e.g. [arithmetic_test.cc](https://github.com/google/highway/blob/master/hwy/tests/arithmetic_test.cc)) also crash with an identical stack, but with no assertion.

Any build command?

https://github.com/llvm/llvm-project/pull/127450