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

Reviewers: rengolin, t.p.northover

Subscribers: aemerson, llvm-commits, rengolin

Differential Revision: http://reviews.llvm.org/D18393

llvm-svn: 264165
diff --git a/llvm/lib/Target/ARM/ARMSubtarget.h b/llvm/lib/Target/ARM/ARMSubtarget.h
index 36b0178..ec1212d 100644
--- a/llvm/lib/Target/ARM/ARMSubtarget.h
+++ b/llvm/lib/Target/ARM/ARMSubtarget.h
@@ -43,8 +43,9 @@
 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
@@ -334,7 +335,7 @@
   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; }