[PATCH] D135462: [SelectionDAG] Do not second-guess alignment for alloca
Eli Friedman via Phabricator via llvm-commits
llvm-commits at lists.llvm.org
Fri Oct 7 11:12:59 PDT 2022
efriedma added a comment.
Given we're de-emphasizing the type of allocas, this probably makes sense? We should be careful that this doesn't have unexpected effects, though; decreasing the alignment of an alloca could affect code generation. (For example, see D134282 <https://reviews.llvm.org/D134282>.)
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Comment at: llvm/lib/CodeGen/SelectionDAG/FunctionLoweringInfo.cpp:137
// The "specified" alignment is the alignment written on the alloca,
// or the preferred alignment of the type if none is specified.
+ Align Alignment = AI->getAlign();
----------------
Outdated comment?
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Comment at: llvm/test/CodeGen/AArch64/preferred-alignment.ll:10
; CHECK-NEXT: add x1, sp, #8
- %i = alloca i32, align 4
+ %i = alloca i32
; CHECK-NEXT: add x2, sp, #4
----------------
Please explicitly specify alignment where possible.
I though the preferred alignment of i8 is 1? I can't see how this change has any practical effect.
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D135462/new/
https://reviews.llvm.org/D135462
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