[PATCH] D150427: [AMDGPU] Non hostcall printf support for HIP

[Sameer Sahasrabuddhe via Phabricator via cfe-commits]

sameerds added inline comments.


================
Comment at: llvm/lib/Transforms/Utils/AMDGPUEmitPrintf.cpp:386-387
+    } else {
+      auto IntTy = dyn_cast<IntegerType>(Args[i]->getType());
+      if (IntTy && IntTy->getBitWidth() == 32)
+        WhatToStore.push_back(
----------------
vikramRH wrote:
> arsenm wrote:
> > vikramRH wrote:
> > > arsenm wrote:
> > > > isIntegerTy(32).
> > > > 
> > > > I also do not understand why only 32-bit integers would be promoted to 64-bit (or why this would be zext). This doesn't match varargs ABI handling, where everything smaller would be promoted to i32.
> > > Right, But default promotions would have happened already, this additional promotion is due to runtime processing requirement
> > Is this documented somewhere? If it's promote everything to i64, I'd prefer to handle all types rather than special casing 32
> That's precisely what the function "fitArgInto64Bits()" did. We eliminated it due to some redundant instructions generated. int32 was the only case (apart from float16 now) that required this special casting.
I think the problem is that the check for "isIntergerTy(32)" makes it look like it is some sort of special case. What we really mean is that if the type is an integer with width less than 64 bits, then zext it with padding to fit the 64-bit store into the buffer. We can do that with just "isIntegerTy()".

Separately, we know from auto promotion of varargs that the integer can only be of size 32 or 64. We can assert that instead of assuming it in the code.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D150427/new/

https://reviews.llvm.org/D150427