PR for llvm/llvm-project#62694 #443
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The x86_intrcc calling convention will build two STACKALLOC_W_PROBING machine instructions if the function takes an error code. This is caused by an additional call to emitSPUpdate in llvm/lib/Target/X86/X86FrameLowering.cpp:1650. Previously only the first STACKALLOC_W_PROBING machine instruction was properly handled, the second one was simply ignored. This lead to miscompilations where the stack pointer wasn't properly updated (see rust-lang/rust#109918). This patch fixes this by handling all STACKALLOC_W_PROBING machine instructions. To be honest I don't quite understand why this didn't lead to more noticeable miscompilations previously. This is my first time contributing to LLVM. Reviewed By: pengfei Differential Revision: https://reviews.llvm.org/D150033 (cherry picked from commit f615436)
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@phoebewang What do you think about merging this PR to the release branch? |
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I don't see any risk to merge this. LGTM. |
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resolves llvm/llvm-project#62694