[X86] Add MOVBE and RDRND features to BDVER4.

Only 6 years behind gcc. https://gcc.gnu.org/legacy-ml/gcc-patches/2014-08/msg00231.html

Found while working on improving how we define CPU features for
clang and auditing for correctness.

Author: topperc

clang/lib/Basic/Targets/X86.cpp

@@ -414,6 +414,8 @@ bool X86TargetInfo::initFeatureMap(
   case CK_BDVER4:
     setFeatureEnabledImpl(Features, "avx2", true);
     setFeatureEnabledImpl(Features, "bmi2", true);
+    setFeatureEnabledImpl(Features, "movbe", true);
+    setFeatureEnabledImpl(Features, "rdrnd", true);
     setFeatureEnabledImpl(Features, "mwaitx", true);
     LLVM_FALLTHROUGH;
   case CK_BDVER3:

clang/test/Preprocessor/predefined-arch-macros.c

@@ -2753,9 +2753,11 @@
 // CHECK_BDVER4_M32: #define __LWP__ 1
 // CHECK_BDVER4_M32: #define __LZCNT__ 1
 // CHECK_BDVER4_M32: #define __MMX__ 1
+// CHECK_BDVER4_M32: #define __MOVBE__ 1
 // CHECK_BDVER4_M32: #define __PCLMUL__ 1
 // CHECK_BDVER4_M32: #define __POPCNT__ 1
 // CHECK_BDVER4_M32: #define __PRFCHW__ 1
+// CHECK_BDVER4_M32: #define __RDRND__ 1
 // CHECK_BDVER4_M32: #define __SSE2_MATH__ 1
 // CHECK_BDVER4_M32: #define __SSE2__ 1
 // CHECK_BDVER4_M32: #define __SSE3__ 1
@@ -2791,9 +2793,11 @@
 // CHECK_BDVER4_M64: #define __LWP__ 1
 // CHECK_BDVER4_M64: #define __LZCNT__ 1
 // CHECK_BDVER4_M64: #define __MMX__ 1
+// CHECK_BDVER4_M64: #define __MOVBE__ 1
 // CHECK_BDVER4_M64: #define __PCLMUL__ 1
 // CHECK_BDVER4_M64: #define __POPCNT__ 1
 // CHECK_BDVER4_M64: #define __PRFCHW__ 1
+// CHECK_BDVER4_M64: #define __RDRND__ 1
 // CHECK_BDVER4_M64: #define __SSE2_MATH__ 1
 // CHECK_BDVER4_M64: #define __SSE2__ 1
 // CHECK_BDVER4_M64: #define __SSE3__ 1

llvm/lib/Target/X86/X86.td

@@ -946,6 +946,8 @@ def ProcessorFeatures {
   // Excavator
   list<SubtargetFeature> BdVer4AdditionalFeatures = [FeatureAVX2,
                                                      FeatureBMI2,
+                                                     FeatureMOVBE,
+                                                     FeatureRDRAND,
                                                      FeatureMWAITX];
   list<SubtargetFeature> BdVer4InheritableFeatures =
     !listconcat(BdVer3InheritableFeatures, BdVer4AdditionalFeatures);