[PATCH] D74794: [X86][ISelLowering] refactor Varargs handling in X86ISelLowering.cpp

[Alexey Lapshin via Phabricator via llvm-commits]

avl marked an inline comment as done.
avl added inline comments.


================
Comment at: llvm/lib/Target/X86/X86ISelLowering.cpp:3523-3524
+                                                   unsigned StackSize) {
+  FuncInfo->setVarArgsFrameIndex(0xAAAAAAA);
+  FuncInfo->setRegSaveFrameIndex(0xAAAAAAA);
+
----------------
aeubanks wrote:
> This isn't the exact same logic as before, is that intended?
Yes. I moved it intentionally. 
To make it clear if *FrameIndex is not set. 
i.e., previously it was set in the very end under some conditions:


```
if (!Is64Bit) {
  // RegSaveFrameIndex is X86-64 only.
  FuncInfo->setRegSaveFrameIndex(0xAAAAAAA);
  if (CallConv == CallingConv::X86_FastCall ||
      CallConv == CallingConv::X86_ThisCall)
  // fastcc functions can't have varargs.
  FuncInfo->setVarArgsFrameIndex(0xAAAAAAA);
}
```

Instead, I always set FrameIndex to an invalid value in the start.
And update it if it really should be set.

Thus if we forget to set that value, we will immediately see 0xAAAAAAA index.


Repository:
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https://reviews.llvm.org/D74794