Fixed LTO issue on no discard variable #1761
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tmiguelf
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LebedevRI
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Mar 5, 2024
LebedevRI
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LebedevRI
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src/benchmark.cc
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| // FIXME: Verify if LTO still messes this up? | ||
| void UseCharPointer(char const volatile* const v) { | ||
| //forces compiler to issue instruction by assigning dummy value to a volatile preventing LTO |
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// We want to escape the pointer `v` so that the compiler can not eliminate computations
// that produced it. To do that, we escape the pointer by storing it into a volatile variable,
// since generally, volatile store, is not something the compiler is allowed to elide.
LebedevRI
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I think this works, at least better than the original: https://godbolt.org/z/v1493hd81
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I'll merge after #1761 unbreaks the CI... |
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Yes, I was having an issue where my code was optimized away and the benchmark::DoNotOptimize failed to prevent optimization. With this it works for my case, now my statistics are more accurate. |
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@tmiguelf thank you! |
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Fixed LTO issue on no discard variable.
Tested on MSVC