[X86] Remove FeatureRTM from Skylake processor list

[thiagomacieira]

Summary

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.

[thiagomacieira]

Matches https://reviews.llvm.org/D53042

[craig.topper]

LGTM

llvm/trunk/lib/Target/X86/X86.td

class BroadwellProc<string Name> : ProcModel<Name, BroadwellModel,
   FeaturePOPCNTFalseDeps,
   FeatureLZCNTFalseDeps
 ]>;
 def : BroadwellProc<"broadwell">;
 
 def SKLFeatures : ProcessorFeatures<BDWFeatures.Value, [
   FeatureAES,
   FeatureMPX,
-  FeatureRTM,
   FeatureXSAVEC,
   FeatureXSAVES,
   FeatureCLFLUSHOPT,
   FeatureFastVectorFSQRT
 ]>;
 
 class SkylakeClientProc<string Name> : ProcModel<Name, SkylakeClientModel,
                                                  SKLFeatures.Value, [

llvm/trunk/test/CodeGen/X86/rtm-schedule.ll

 ; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
-; RUN: llc < %s -mtriple=x86_64-unknown-unknown -print-schedule -mcpu=x86-64 -mattr=+rtm | FileCheck %s --check-prefix=CHECK --check-prefix=GENERIC
-; RUN: llc < %s -mtriple=x86_64-unknown-unknown -print-schedule -mcpu=skylake | FileCheck %s --check-prefix=CHECK --check-prefix=SKYLAKE --check-prefix=SKL
-; RUN: llc < %s -mtriple=x86_64-unknown-unknown -print-schedule -mcpu=skx | FileCheck %s --check-prefix=CHECK --check-prefix=SKYLAKE --check-prefix=SKX
-; RUN: llc < %s -mtriple=x86_64-unknown-unknown -print-schedule -mcpu=cannonlake | FileCheck %s --check-prefix=CHECK --check-prefix=SKYLAKE --check-prefix=CNL
-; RUN: llc < %s -mtriple=x86_64-unknown-unknown -print-schedule -mcpu=icelake-client | FileCheck %s --check-prefix=CHECK --check-prefix=SKYLAKE --check-prefix=ICL
-; RUN: llc < %s -mtriple=x86_64-unknown-unknown -print-schedule -mcpu=icelake-server | FileCheck %s --check-prefix=CHECK --check-prefix=SKYLAKE --check-prefix=ICL
+; RUN: llc < %s -mtriple=x86_64-unknown-unknown -print-schedule -mattr=+rtm -mcpu=x86-64 -mattr=+rtm | FileCheck %s --check-prefix=CHECK --check-prefix=GENERIC
+; RUN: llc < %s -mtriple=x86_64-unknown-unknown -print-schedule -mattr=+rtm -mcpu=skylake | FileCheck %s --check-prefix=CHECK --check-prefix=SKYLAKE --check-prefix=SKL
+; RUN: llc < %s -mtriple=x86_64-unknown-unknown -print-schedule -mattr=+rtm -mcpu=skx | FileCheck %s --check-prefix=CHECK --check-prefix=SKYLAKE --check-prefix=SKX
+; RUN: llc < %s -mtriple=x86_64-unknown-unknown -print-schedule -mattr=+rtm -mcpu=cannonlake | FileCheck %s --check-prefix=CHECK --check-prefix=SKYLAKE --check-prefix=CNL
+; RUN: llc < %s -mtriple=x86_64-unknown-unknown -print-schedule -mattr=+rtm -mcpu=icelake-client | FileCheck %s --check-prefix=CHECK --check-prefix=SKYLAKE --check-prefix=ICL
+; RUN: llc < %s -mtriple=x86_64-unknown-unknown -print-schedule -mattr=+rtm -mcpu=icelake-server | FileCheck %s --check-prefix=CHECK --check-prefix=SKYLAKE --check-prefix=ICL
 
 define i32 @test_xbegin() nounwind uwtable {
 ; GENERIC-LABEL: test_xbegin:
 ; GENERIC:       # %bb.0:
 ; GENERIC-NEXT:    xbegin .LBB0_2 # sched: [100:0.33]
 ; GENERIC-NEXT:  # %bb.1:
 ; GENERIC-NEXT:    movl $-1, %eax # sched: [1:0.33]
 ; GENERIC-NEXT:    retq # sched: [1:1.00]