[PATCH] D29284: [AMDGPU] Lower null pointers in static variable initializer

[Yaxun Liu via Phabricator via llvm-commits]

yaxunl added inline comments.


================
Comment at: lib/Target/AMDGPU/Utils/AMDGPUConstantFoldUtils.cpp:17
+
+bool isNonZeroNullPointer(const Constant *CV) {
+  auto CE = dyn_cast<ConstantExpr>(CV);
----------------
arsenm wrote:
> This doesn't need to be its own file and isn't the right API to be re-used. I think the right place is in AMDGPUTargetMachine because this is logically part of the DataLayout.
> 
> The base function should just be the address spaces so it can be used in the DAG and MI
I took a look of TargetMachine and its derived classes, I did not see a precedence to put such information there. Is it the right place to hold such information?

Another question. I am not quite sure about the desired API for this function. Do you want something like this?


```
uint64_t getNullPointerValue(unsigned AddrSpace);
```

which returns -1 for private/local address spaces and 0 for other address spaces?


https://reviews.llvm.org/D29284