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Use separate memcpy source/dest alignments in LLVM 7 #49740

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hanna-kruppe opened this issue Apr 6, 2018 · 0 comments
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Use separate memcpy source/dest alignments in LLVM 7 #49740

hanna-kruppe opened this issue Apr 6, 2018 · 0 comments
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A-LLVM Area: Code generation parts specific to LLVM. Both correctness bugs and optimization-related issues. C-enhancement Category: An issue proposing an enhancement or a PR with one. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue.

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@hanna-kruppe
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LLVM trunk recently switched from a single alignment argument that applies to source and destination to annotating both the source and destination pointers with their respective alignment. See https://lists.llvm.org/pipermail/llvm-dev/2018-March/122143.html and the rest of that thread for details.

After we upgrade to LLVM 7, we should try to make use of that anywhere we know that the source and destination have different alignments. cc @eddyb
@hanna-kruppe hanna-kruppe changed the title Use separate source/dest alignments in LLVM 7 Use separate memcpy source/dest alignments in LLVM 7 Apr 6, 2018
@XAMPPRocky XAMPPRocky added A-LLVM Area: Code generation parts specific to LLVM. Both correctness bugs and optimization-related issues. C-enhancement Category: An issue proposing an enhancement or a PR with one. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. labels Jun 30, 2018
@nikic nikic mentioned this issue Nov 2, 2018
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bors added a commit that referenced this issue Nov 8, 2018
@bors
Auto merge of #55633 - nikic:memcpy-align, r=nagisa
3cb9d37 
Support memcpy/memmove with differing src/dst alignment

If LLVM 7 is used, generate memcpy/memmove with differing src/dst alignment. I've added new FFI functions to construct these through the builder API, which is more convenient than dealing with differing intrinsic signatures depending on the LLVM version.

Fixes #49740.
Mark-Simulacrum added a commit to Mark-Simulacrum/rust that referenced this issue Nov 9, 2018
@Mark-Simulacrum
Rollup merge of rust-lang#55633 - nikic:memcpy-align, r=nagisa
78cab36 
Support memcpy/memmove with differing src/dst alignment

If LLVM 7 is used, generate memcpy/memmove with differing src/dst alignment. I've added new FFI functions to construct these through the builder API, which is more convenient than dealing with differing intrinsic signatures depending on the LLVM version.

Fixes rust-lang#49740.
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A-LLVM Area: Code generation parts specific to LLVM. Both correctness bugs and optimization-related issues. C-enhancement Category: An issue proposing an enhancement or a PR with one. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue.
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