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

[Thiago Macieira via Phabricator via cfe-commits]

thiagomacieira created this revision.
thiagomacieira added reviewers: erichkeane, craig.topper.
Herald added a subscriber: cfe-commits.
craig.topper retitled this revision from "Remove FeatureRTM from Skylake processor list" to "[X86] Remove FeatureRTM from Skylake processor list".

There are a LOT of Skylakes and later without TSX-NI. Examples:

- SKL: https://ark.intel.com/products/136863/Intel-Core-i3-8121U-Processor-4M-Cache-up-to-3-20-GHz-
- KBL: https://ark.intel.com/products/97540/Intel-Core-i7-7560U-Processor-4M-Cache-up-to-3-80-GHz-
- KBL-R: https://ark.intel.com/products/149091/Intel-Core-i7-8565U-Processor-8M-Cache-up-to-4-60-GHz-
- CNL: https://ark.intel.com/products/136863/Intel-Core-i3-8121U-Processor-4M-Cache-up-to-3_20-GHz

This feature seems to be present only on high-end desktop and server
chips (I can't find any SKX without). This commit leaves it disabled
for all processors, but can be re-enabled for specific builds with
-mrtm.

Matches https://reviews.llvm.org/D53041


Repository:
  rC Clang

https://reviews.llvm.org/D53042

Files:
  lib/Basic/Targets/X86.cpp


Index: lib/Basic/Targets/X86.cpp
===================================================================
--- lib/Basic/Targets/X86.cpp
+++ lib/Basic/Targets/X86.cpp
@@ -169,7 +169,6 @@
     if (Kind != CK_SkylakeServer) // SKX inherits all SKL features, except SGX
       setFeatureEnabledImpl(Features, "sgx", true);
     setFeatureEnabledImpl(Features, "clflushopt", true);
-    setFeatureEnabledImpl(Features, "rtm", true);
     setFeatureEnabledImpl(Features, "aes", true);
     LLVM_FALLTHROUGH;
   case CK_Broadwell:


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