Replace a string comparison in ARMSubtarget.h with a tablegen entry in ARM.td (NFC)

[rengolin]

Obvious patch. LGTM. Thanks!

lib/Target/ARM/ARM.td

 
 def ProcR4      : SubtargetFeature<"r4", "ARMProcFamily", "CortexR4",
                                    "Cortex-R4 ARM processors", []>;
 def ProcR5      : SubtargetFeature<"r5", "ARMProcFamily", "CortexR5",
                                    "Cortex-R5 ARM processors", []>;
 def ProcR7      : SubtargetFeature<"r7", "ARMProcFamily", "CortexR7",
                                    "Cortex-R7 ARM processors", []>;
 
+def ProcM3      : SubtargetFeature<"m3", "ARMProcFamily", "CortexM3",
+                                   "Cortex-M3 ARM processors", []>;
 
 //===----------------------------------------------------------------------===//
 // ARM schedules.
 //
 
 include "ARMSchedule.td"
 
 
def : ProcessorModel<"cortex-r8",   CortexA8Model,      [ARMv7r,
                                                          FeatureFP16,
                                                          FeatureMP,
                                                          FeatureSlowFPBrcc,
                                                          FeatureHWDivARM,
                                                          FeatureHasSlowFPVMLx,
                                                          FeatureAvoidPartialCPSR,
                                                          FeatureT2XtPk]>;
 
-def : ProcNoItin<"cortex-m3",                           [ARMv7m]>;
-def : ProcNoItin<"sc300",                               [ARMv7m]>;
+def : ProcNoItin<"cortex-m3",                           [ARMv7m, ProcM3]>;
+def : ProcNoItin<"sc300",                               [ARMv7m, ProcM3]>;
 
 def : ProcNoItin<"cortex-m4",                           [ARMv7em,
                                                          FeatureVFP4,
                                                          FeatureVFPOnlySP,
                                                          FeatureD16]>;
 
 def : ProcNoItin<"cortex-m7",                           [ARMv7em,
                                                          FeatureFPARMv8,

lib/Target/ARM/ARMSubtarget.h

 class StringRef;
 class TargetOptions;
 class ARMBaseTargetMachine;
 
 class ARMSubtarget : public ARMGenSubtargetInfo {
 protected:
   enum ARMProcFamilyEnum {
     Others, CortexA5, CortexA7, CortexA8, CortexA9, CortexA12, CortexA15,
-    CortexA17, CortexR4, CortexR4F, CortexR5, CortexR7, CortexA32, CortexA35,
-    CortexA53, CortexA57, CortexA72, Krait, Swift, ExynosM1
+    CortexA17, CortexR4, CortexR4F, CortexR5, CortexR7, CortexM3,
+    CortexA32, CortexA35, CortexA53, CortexA57, CortexA72,
+    Krait, Swift, ExynosM1
   };
   enum ARMProcClassEnum {
     None, AClass, RClass, MClass
   };
   enum ARMArchEnum {
     ARMv2, ARMv2a, ARMv3, ARMv3m, ARMv4, ARMv4t, ARMv5, ARMv5t, ARMv5te,
     ARMv5tej, ARMv6, ARMv6k, ARMv6kz, ARMv6t2, ARMv6m, ARMv6sm, ARMv7a, ARMv7r,
     ARMv7m, ARMv7em, ARMv8a, ARMv81a, ARMv82a, ARMv8mMainline, ARMv8mBaseline
public:
   bool hasV8MMainlineOps() const { return HasV8MMainlineOps; }
 
   bool isCortexA5() const { return ARMProcFamily == CortexA5; }
   bool isCortexA7() const { return ARMProcFamily == CortexA7; }
   bool isCortexA8() const { return ARMProcFamily == CortexA8; }
   bool isCortexA9() const { return ARMProcFamily == CortexA9; }
   bool isCortexA15() const { return ARMProcFamily == CortexA15; }
   bool isSwift()    const { return ARMProcFamily == Swift; }
-  bool isCortexM3() const { return CPUString == "cortex-m3"; }
+  bool isCortexM3() const { return ARMProcFamily == CortexM3; }
   bool isLikeA9() const { return isCortexA9() || isCortexA15() || isKrait(); }
   bool isCortexR5() const { return ARMProcFamily == CortexR5; }
   bool isKrait() const { return ARMProcFamily == Krait; }
 
   bool hasARMOps() const { return !NoARM; }
 
   bool hasVFP2() const { return HasVFPv2; }
   bool hasVFP3() const { return HasVFPv3; }