[llvm-dev] Weird pointer alignment behavior on x86_32 - intentional or not?

Karl Rehm via llvm-dev llvm-dev at lists.llvm.org
Mon Jun 14 19:28:01 PDT 2021

Update: This might be an issue with optimization ordering. Forcing
DAGCombiner::isAlias to return true (everything aliases) causes things to
go as expected. The difference in architectures is because the alignment on
other platforms is 4 bytes whereas on Windows it's 8, causing the alias
analysis to succeed on Windows but not on other platforms.

On Mon, Jun 14, 2021 at 6:32 PM Karl Rehm <klrehm123 at gmail.com> wrote:

> Hello,
> I'm trying to figure out why LLVM generates different code between Windows
> and other targets when it comes to a simple pointer dereference. I've
> narrowed it down to alignment, but I'm confused as to why this happens. Is
> this behavior intentional?
> https://godbolt.org/z/f18WxzW11
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