Use more LLVM_ENABLE_ABI_BREAKING_CHECKS in Error.h

[aaronpuchert]

Summary

If we don't read the flag, we don't need to set it. Then we also don't
need to filter it out to get the pointer.

This should have a (small) positive impact on code size and performance.

[dblaikie]

Pinging @lhames

[lhames]

LGTM. Thanks Aaron!

llvm/include/llvm/Support/Error.h

#endif
   void assertIsChecked() {
 #if LLVM_ENABLE_ABI_BREAKING_CHECKS
     if (LLVM_UNLIKELY(!getChecked() || getPtr()))
       fatalUncheckedError();
 #endif
   }
 
   ErrorInfoBase *getPtr() const {
+#if LLVM_ENABLE_ABI_BREAKING_CHECKS
     return reinterpret_cast<ErrorInfoBase*>(
              reinterpret_cast<uintptr_t>(Payload) &
              ~static_cast<uintptr_t>(0x1));
+#else
+    return Payload;
+#endif
   }
 
   void setPtr(ErrorInfoBase *EI) {
 #if LLVM_ENABLE_ABI_BREAKING_CHECKS
     Payload = reinterpret_cast<ErrorInfoBase*>(
                 (reinterpret_cast<uintptr_t>(EI) &
                  ~static_cast<uintptr_t>(0x1)) |
                 (reinterpret_cast<uintptr_t>(Payload) & 0x1));
 #else
     Payload = EI;
 #endif
   }
 
   bool getChecked() const {
 #if LLVM_ENABLE_ABI_BREAKING_CHECKS
     return (reinterpret_cast<uintptr_t>(Payload) & 0x1) == 0;
 #else
     return true;
 #endif
   }
 
   void setChecked(bool V) {
+#if LLVM_ENABLE_ABI_BREAKING_CHECKS
     Payload = reinterpret_cast<ErrorInfoBase*>(
                 (reinterpret_cast<uintptr_t>(Payload) &
                   ~static_cast<uintptr_t>(0x1)) |
                   (V ? 0 : 1));
+#endif
   }
 
   std::unique_ptr<ErrorInfoBase> takePayload() {
     std::unique_ptr<ErrorInfoBase> Tmp(getPtr());
     setPtr(nullptr);
     setChecked(true);
     return Tmp;
   }