[llvm-dev] [Release-testers] [7.0.0 Release] rc1 has been tagged

[Joerg Sonnenberger via llvm-dev]

On Tue, Aug 07, 2018 at 09:49:16PM +0200, Dimitry Andric via llvm-dev wrote:
> This is a regression caused by https://reviews.llvm.org/rL323281:
> 
> ------------------------------------------------------------------------
> r323281 | wmi | 2018-01-23 23:27:57 +0000 (Tue, 23 Jan 2018) | 12 lines
> 
> Adjust MaxAtomicInlineWidth for i386/i486 targets.
> 
> This is to fix the bug reported in https://bugs.llvm.org/show_bug.cgi?id=34347#c6.
> Currently, all  MaxAtomicInlineWidth of x86-32 targets are set to 64. However,
> i386 doesn't support any cmpxchg related instructions. i486 only supports cmpxchg.
> So in this patch MaxAtomicInlineWidth is reset as follows:
> For i386, the MaxAtomicInlineWidth should be 0 because no cmpxchg is supported.
> For i486, the MaxAtomicInlineWidth should be 32 because it supports cmpxchg.
> For others 32 bits x86 cpu, the MaxAtomicInlineWidth should be 64 because of cmpxchg8b.

This seems to be somewhat undesirable. Does *anyone* care about real
i386 support at this point? NetBSD certainly doesn't and I think we are
already the odd man for a number of cases like this.

Joerg