[PATCH] D96351: [AIX] Enable the default AltiVec ABI on AIX

[Hubert Tong via Phabricator via llvm-commits]

hubert.reinterpretcast added inline comments.


================
Comment at: llvm/lib/Target/PowerPC/PPCISelLowering.cpp:15165-15166
+    if (R.first >= (PPC::V0 + 20) && R.second == &PPC::VSRCRegClass)
+      errs() << "warning: vector registers 20 to 32 are reserved in the "
+                "default AIX AltiVec ABI and cannot be used\n";
+  }
----------------
ZarkoCA wrote:
> hubert.reinterpretcast wrote:
> > Is there a lot of precedent for "raw output" to stderr for warnings from the back-end? Can we diagnose this closer to where `err_asm_unknown_register_name` is handled in the front-end?
> I've seen some cases in other targets but, no, there is not a lot of precedent for this in  PPC subtarget. 
> 
> I investigated with making the suggested change where `err_asm_unknown_register_name` is handled in clang but it seems to me making the changes there is at least a patch of its own.  I wasn't able to find an efficient way to do it for now using that method.  
> 
> If you feel strongly about this, I could remove the warning here and then make a follow on patch to add the warning the front end. My own feeling is that the warning should come from the frond end and this is a comprise for now.
I think having something here for now is better than having nothing. Please add a FIXME comment to implement the warning in the front-end to replace this one (and do the follow up patch after dealing with the functional issues on your plate for vector support right now).

Also, can you point me to the test for this?


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D96351/new/

https://reviews.llvm.org/D96351