[PATCH] D132910: [SimplifyCFG] add a test for branch folding multiple BB

[Yaxun Liu via Phabricator via llvm-commits]

yaxunl marked an inline comment as done.
yaxunl added inline comments.


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Comment at: llvm/test/Transforms/SimplifyCFG/branch-fold-multiple.ll:5
+
+target triple = "amdgcn-amd-amdhsa"
+
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fhahn wrote:
> Does this need to be target specific? We should definitely have at least some target-independent tests here.
The cost of bonus instructions depends on the target triple and processor (https://github.com/llvm/llvm-project/blob/main/llvm/lib/Transforms/Utils/SimplifyCFG.cpp#L3676). Certain processors have high costs than others, causing the branch not to be folded.

For example, if I replace the target triple of this lit test with `x86_64` and remove the target processor. This lit test still passes since `x86_64` behaves similarly as amdgcn gfx906. However, if I replace the target triple with `x86`, this lit test will fail since the branches are never folded even without my patch.

How about I make the IR in this lit test target independent, and use `-mtriple` to test a few triples which are relevant to the test?


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  https://reviews.llvm.org/D132910/new/

https://reviews.llvm.org/D132910