[clang] [libc] [llvm] [libc] Implement (v|f)printf on the GPU (PR #96369)

[Jon Chesterfield via cfe-commits]

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@@ -215,7 +219,10 @@ void NVPTXABIInfo::computeInfo(CGFunctionInfo &FI) const {
 
 RValue NVPTXABIInfo::EmitVAArg(CodeGenFunction &CGF, Address VAListAddr,
                                QualType Ty, AggValueSlot Slot) const {
-  llvm_unreachable("NVPTX does not support varargs");
+  return emitVoidPtrVAArg(CGF, VAListAddr, Ty, /*IsIndirect=*/false,
+                          getContext().getTypeInfoInChars(Ty),
+                          CharUnits::fromQuantity(4),
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JonChesterfield wrote:

Error is here - this says slots shall be at least four bytes in size, but nvcc looks happy to pass struct {char} right next to other things, so we're looking for CharUnits::fromQuantity(1),

https://github.com/llvm/llvm-project/pull/96369