[PATCH] D53042: [X86] Remove FeatureRTM from Skylake processor list

[Thiago Macieira via Phabricator via cfe-commits]

thiagomacieira added inline comments.


================
Comment at: lib/Basic/Targets/X86.cpp:169
     setFeatureEnabledImpl(Features, "mpx", true);
     if (Kind != CK_SkylakeServer) // SKX inherits all SKL features, except SGX
       setFeatureEnabledImpl(Features, "sgx", true);
----------------
craig.topper wrote:
> craig.topper wrote:
> > lebedev.ri wrote:
> > > > high-end desktop and server chips (I can't find any SKX without).
> > > 
> > > Are you sure you didn't want to move it into an else of this `if()` ?
> > > This commit leaves it disabled for all processors, but can be re-enabled for specific builds with -mrtm.
> > 
> > So I think this was intended.
> It's also consistent with gcc based on grepping for _RTM_ in their predefined macro output. https://godbolt.org/z/dtfrQU They don't infer it from -mcpu=skylake-avx512, but do when adding -mrtm
I'm sure I didn't want to :-) Do you want me to do that? And do you want me to do it for IcelakeServer too?

This matches GCC's behaviour:

```
$ gcc -march=skylake-avx512 -dM -E -xc /dev/null | grep -c RTM
0
```


Repository:
  rC Clang

https://reviews.llvm.org/D53042