Set exact flag on index_castui during iree-util-optimize-int-arithmetic#23667
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amd-eochoalo wants to merge 4 commits intoiree-org:mainfrom
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Set exact flag on index_castui during iree-util-optimize-int-arithmetic#23667amd-eochoalo wants to merge 4 commits intoiree-org:mainfrom
amd-eochoalo wants to merge 4 commits intoiree-org:mainfrom
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Converting back to draft. I'll add exact instead on one of the passes like |
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kuhar
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@RattataKing I'll merge after your LLVM integration, so no need to worry about this PR. I'll also point to the new LLVM branch. |
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I'm going to flag that these patterns also exist upstream, and that there are a few other spots in IREE where we generate index_cast ops. |
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I'm closing this without merging due to it being reverted upstream. See llvm/llvm-project#184876 |
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Since llvm/llvm-project#183395 was merged upstream,
optimization of index_cast(index_cast(x)) -> x requires the exact flag.
This pattern without the exact flag is unsound since the size of index is assumed to be 64 bits
but that is not always the case.
IREE applies this pattern when running --iree-util-optimize-int-arithmetic.
This pass uses the util dialect to prove the correctness of transforming signed operations into unsigned operations.
We take advantage of this to set the exact flag which allows the pattern to get applied soundly.