Set both nuw and nsw in slice size calculation
#136575
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Probably won't change that much, but let's see |
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Set both `nuw` and `nsw` in slice size calculation There's an old note in the code to do this, and now that [LLVM-C has an API for it](https://github.com/llvm/llvm-project/blob/f0b8ff12519270adcfef93410abff76ab073476a/llvm/include/llvm-c/Core.h#L4403-L4408), we might as well. And it's been there since what looks like LLVM 17 llvm/llvm-project@de9b6aa so doesn't even need to be conditional. (There's other places, like `RawVecInner` or `Layout`, that might want to do things like this too, but I'll leave those for a future PR.)
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☀️ Try build successful - checks-actions |
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Finished benchmarking commit (c304764): comparison URL. Overall result: ❌ regressions - no action neededBenchmarking this pull request likely means that it is perf-sensitive, so we're automatically marking it as not fit for rolling up. While you can manually mark this PR as fit for rollup, we strongly recommend not doing so since this PR may lead to changes in compiler perf. @bors rollup=never Instruction countThis is the most reliable metric that we have; it was used to determine the overall result at the top of this comment. However, even this metric can sometimes exhibit noise.
Max RSS (memory usage)Results (primary 6.5%)This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.
CyclesThis benchmark run did not return any relevant results for this metric. Binary sizeThis benchmark run did not return any relevant results for this metric. Bootstrap: 779.293s -> 779.494s (0.03%) |
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Allows a bit more optimization without a compile-time perf change, so looks ready to go to me 👍 |
| // CHECK-LABEL: @slice_size_plus_2 | ||
| #[no_mangle] | ||
| pub fn slice_size_plus_2(x: &[u16]) -> usize { | ||
| // Before #136575 this didn't get the `nuw` in the add. |
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☔ The latest upstream changes (presumably #136965) made this pull request unmergeable. Please resolve the merge conflicts. |
There's an old note in the code to do this, and now that LLVM-C has an API for it, we might as well.
| @@ -1430,6 +1430,8 @@ unsafe extern "C" { | |||
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| // Extra flags on arithmetic | |||
| pub(crate) fn LLVMSetIsDisjoint(Instr: &Value, IsDisjoint: Bool); | |||
| pub(crate) fn LLVMSetNUW(ArithInst: &Value, HasNUW: Bool); | |||
| pub(crate) fn LLVMSetNSW(ArithInst: &Value, HasNSW: Bool); | |||
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annot: Rebased to address the conflict, and updated these to pub(crate) following #136881
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@bors r+ |
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☀️ Test successful - checks-actions |
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Finished benchmarking commit (bdc97d1): comparison URL. Overall result: no relevant changes - no action needed@rustbot label: -perf-regression Instruction countThis benchmark run did not return any relevant results for this metric. Max RSS (memory usage)Results (primary -2.2%)This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.
CyclesThis benchmark run did not return any relevant results for this metric. Binary sizeThis benchmark run did not return any relevant results for this metric. Bootstrap: 789.359s -> 790.438s (0.14%) |
There's an old note in the code to do this, and now that LLVM-C has an API for it, we might as well. And it's been there since what looks like LLVM 17 llvm/llvm-project@de9b6aa so doesn't even need to be conditional.
(There's other places, like
RawVecInnerorLayout, that might want to do things like this too, but I'll leave those for a future PR.)