[llvm] [GlobalOpt] Add TTI interface useFastCCForInternalCall for FASTCC (PR #164768)

[Phoebe Wang via llvm-commits]

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@@ -319,6 +319,10 @@ class X86TTIImpl final : public BasicTTIImplBase<X86TTIImpl> {
   unsigned getStoreMinimumVF(unsigned VF, Type *ScalarMemTy,
                              Type *ScalarValTy) const override;
 
+  bool useFastCCForInternalCall(Function &F) const override {
+    return !ST->is64Bit() || ST->hasEGPR();
+  }
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phoebewang wrote:

I think single direction is enough. We can call a function without EGPR from EGPR enabled function, but not the opposite direction.

https://github.com/llvm/llvm-project/pull/164768