shchenz added a comment.
Can we use the feature bit `FeatureQuadwordAtomic` to decide whether QuadAtomic
is supported or not on AIX? Like what we do for Linux.
The reason we need this option is: we may need to compile a lock free libatomic
on a Power7 or below target? If so, do we have similar issue on Linux? Thanks.
================
Comment at: clang/include/clang/Driver/Options.td:3611
HelpText<"Enable the default Altivec ABI on AIX (AIX only). Uses only
volatile vector registers.">;
+def maix_quadword_atomics : Flag<["-"], "maix64-quadword-atomics">,
+ Group<m_Group>, Flags<[CC1Option]>,
----------------
amyk wrote:
> Would it be better if we called this `maix64-quadword-atomics` instead?
Do we need to change the backend check below too?
```
bool PPCTargetLowering::shouldInlineQuadwordAtomics() const {
// TODO: 16-byte atomic type support for AIX is in progress; we should be able
// to inline 16-byte atomic ops on AIX too in the future.
return Subtarget.isPPC64() &&
(EnableQuadwordAtomics || !Subtarget.getTargetTriple().isOSAIX()) &&
Subtarget.hasQuadwordAtomics();
}
```
================
Comment at: clang/lib/Basic/Targets/PPC.cpp:854
+ HasQuadwordAtomics)
+ MaxAtomicInlineWidth = 128;
}
----------------
Can we set `MaxAtomicInlineWidth` in `PPC64TargetInfo::setMaxAtomicWidth()`?
There is a `TODO` there
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D127189/new/
https://reviews.llvm.org/D127189
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