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b2728d5426
Update our range `assume`s to the format that LLVM prefers I found out in https://github.com/llvm/llvm-project/issues/123278#issuecomment-2597440158 that the way I started emitting the `assume`s in #109993 was suboptimal, and as seen in that LLVM issue the way we're doing it -- with two `assume`s sometimes -- can at times lead to CVP/SCCP not realize what's happening because one of them turns into a `ne` instead of conveying a range. So this updates how it's emitted from ``` assume( x >= LOW ); assume( x <= HIGH ); ``` or ``` // (for ranges that wrap the range) assume( (x <= LOW) | (x >= HIGH) ); ``` to ``` assume( (x - LOW) <= (HIGH - LOW) ); ``` so that we don't need multiple `icmp`s nor multiple `assume`s for a single value, and both wrappping and non-wrapping ranges emit the same shape. (And we don't bother emitting the subtraction if `LOW` is zero, since that's trivial for us to check too.) |
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| README.md | ||
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