https://bugs.winehq.org/show_bug.cgi?id=55470
--- Comment #8 from Zeb Figura z.figura12@gmail.com --- (In reply to Stefan Dösinger from comment #7)
There are a lot of compiler alignment related bugs. I am not opposed to closing this one (or others) as duplicates. How the compiler ends up generating alignment dependent code (either by explicit request like in my C sample or via SSE) is I think less important than that gcc uses the wrong defaults when targeting x86 Windows.
Well, the critical point is that it doesn't, though; gcc *does* in general agree that i386-w64-mingw has a stack alignment of 4. You can see this when it generates SSE instructions (except for the conditions of bug 55007). But for some reason that doesn't apply to manually aligned types.