[AArch64] Implement the getCSRFirstUseCost API, mirroring that in ARM64.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@206473 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/AArch64/AArch64RegisterInfo.h b/lib/Target/AArch64/AArch64RegisterInfo.h
index bb26f1ac9a6e37cc05dc287bd84bb81f093245cb..5e9542a4dcfbe4a0119d8b2b13e8d99cb012a26d 100644 (file)
--- a/lib/Target/AArch64/AArch64RegisterInfo.h
+++ b/lib/Target/AArch64/AArch64RegisterInfo.h
@@ -30,6 +30,13 @@ struct AArch64RegisterInfo : public AArch64GenRegisterInfo {
   const MCPhysReg *getCalleeSavedRegs(const MachineFunction *MF = 0) const;
   const uint32_t *getCallPreservedMask(CallingConv::ID) const;
 
+  unsigned getCSRFirstUseCost() const {
+    // The cost will be compared against BlockFrequency where entry has the
+    // value of 1 << 14. A value of 5 will choose to spill or split really
+    // cold path instead of using a callee-saved register.
+    return 5;
+  }
+
   const uint32_t *getTLSDescCallPreservedMask() const;
 
   BitVector getReservedRegs(const MachineFunction &MF) const;