Index: include/llvm/Support/ARMTargetParser.def
===================================================================
--- include/llvm/Support/ARMTargetParser.def
+++ include/llvm/Support/ARMTargetParser.def
@@ -104,23 +104,24 @@
 #undef ARM_ARCH
 
 #ifndef ARM_ARCH_EXT_NAME
-#define ARM_ARCH_EXT_NAME(NAME, ID)
+#define ARM_ARCH_EXT_NAME(NAME, ID, FEATURE, NEGFEATURE)
 #endif
-ARM_ARCH_EXT_NAME("invalid", AEK_INVALID)
-ARM_ARCH_EXT_NAME("none", AEK_NONE)
-ARM_ARCH_EXT_NAME("crc", AEK_CRC)
-ARM_ARCH_EXT_NAME("crypto", AEK_CRYPTO)
-ARM_ARCH_EXT_NAME("fp", AEK_FP)
-ARM_ARCH_EXT_NAME("idiv", (AEK_HWDIVARM | AEK_HWDIV))
-ARM_ARCH_EXT_NAME("mp", AEK_MP)
-ARM_ARCH_EXT_NAME("simd", AEK_SIMD)
-ARM_ARCH_EXT_NAME("sec", AEK_SEC)
-ARM_ARCH_EXT_NAME("virt", AEK_VIRT)
-ARM_ARCH_EXT_NAME("os", AEK_OS)
-ARM_ARCH_EXT_NAME("iwmmxt", AEK_IWMMXT)
-ARM_ARCH_EXT_NAME("iwmmxt2", AEK_IWMMXT2)
-ARM_ARCH_EXT_NAME("maverick", AEK_MAVERICK)
-ARM_ARCH_EXT_NAME("xscale", AEK_XSCALE)
+// FIXME: This would be nicer were it tablegen
+ARM_ARCH_EXT_NAME("invalid",  AEK_INVALID,  nullptr,  nullptr)
+ARM_ARCH_EXT_NAME("none",     AEK_NONE,     nullptr,  nullptr)
+ARM_ARCH_EXT_NAME("crc",      AEK_CRC,      "+crc",   "-crc")
+ARM_ARCH_EXT_NAME("crypto",   AEK_CRYPTO,   "+crypto","-crypto")
+ARM_ARCH_EXT_NAME("fp",       AEK_FP,       nullptr,  nullptr)
+ARM_ARCH_EXT_NAME("idiv",     (AEK_HWDIVARM | AEK_HWDIV), nullptr, nullptr)
+ARM_ARCH_EXT_NAME("mp",       AEK_MP,       nullptr,  nullptr)
+ARM_ARCH_EXT_NAME("simd",     AEK_SIMD,     nullptr,  nullptr)
+ARM_ARCH_EXT_NAME("sec",      AEK_SEC,      nullptr,  nullptr)
+ARM_ARCH_EXT_NAME("virt",     AEK_VIRT,     nullptr,  nullptr)
+ARM_ARCH_EXT_NAME("os",       AEK_OS,       nullptr,  nullptr)
+ARM_ARCH_EXT_NAME("iwmmxt",   AEK_IWMMXT,   nullptr,  nullptr)
+ARM_ARCH_EXT_NAME("iwmmxt2",  AEK_IWMMXT2,  nullptr,  nullptr)
+ARM_ARCH_EXT_NAME("maverick", AEK_MAVERICK, nullptr,  nullptr)
+ARM_ARCH_EXT_NAME("xscale",   AEK_XSCALE,   nullptr,  nullptr)
 #undef ARM_ARCH_EXT_NAME
 
 #ifndef ARM_HW_DIV_NAME
Index: include/llvm/Support/TargetParser.h
===================================================================
--- include/llvm/Support/TargetParser.h
+++ include/llvm/Support/TargetParser.h
@@ -119,6 +119,7 @@
 StringRef getCPUAttr(unsigned ArchKind);
 StringRef getSubArch(unsigned ArchKind);
 StringRef getArchExtName(unsigned ArchExtKind);
+const char *getArchExtFeature(StringRef ArchExt);
 StringRef getHWDivName(unsigned HWDivKind);
 
 // Information by Name
Index: lib/Support/TargetParser.cpp
===================================================================
--- lib/Support/TargetParser.cpp
+++ lib/Support/TargetParser.cpp
@@ -16,6 +16,7 @@
 #include "llvm/Support/TargetParser.h"
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/ADT/StringSwitch.h"
+#include "llvm/ADT/Twine.h"
 #include <cctype>
 
 using namespace llvm;
@@ -82,10 +83,14 @@
   const char *NameCStr;
   size_t NameLength;
   unsigned ID;
+  const char *Feature;
+  const char *NegFeature;
 
   StringRef getName() const { return StringRef(NameCStr, NameLength); }
+  StringRef getNegName() const { return (Twine("no") + getName()).str(); }
 } ARCHExtNames[] = {
-#define ARM_ARCH_EXT_NAME(NAME, ID) { NAME, sizeof(NAME) - 1, ID },
+#define ARM_ARCH_EXT_NAME(NAME, ID, FEATURE, NEGFEATURE) \
+  { NAME, sizeof(NAME) - 1, ID, FEATURE, NEGFEATURE },
 #include "llvm/Support/ARMTargetParser.def"
 };
 
@@ -326,6 +331,17 @@
   return StringRef();
 }
 
+const char *llvm::ARM::getArchExtFeature(StringRef ArchExt) {
+  for (const auto AE : ARCHExtNames) {
+    if (AE.Feature && ArchExt == AE.getName())
+      return AE.Feature;
+    else if (AE.NegFeature && ArchExt == AE.getNegName())
+      return AE.NegFeature;
+  }
+
+  return nullptr;
+}
+
 StringRef llvm::ARM::getHWDivName(unsigned HWDivKind) {
   for (const auto D : HWDivNames) {
     if (HWDivKind == D.ID)