[PATCH] D103138: [AMDGPU] [IndirectCalls] Don't propagate attributes to address taken functions and their callees

[Madhur Amilkanthwar via Phabricator via llvm-commits]

madhur13490 added inline comments.


================
Comment at: llvm/lib/Target/AMDGPU/AMDGPUPropagateAttributes.cpp:234-237
+  if (!ModuleCG) {
+    llvm_unreachable("Call graph not valid");
+    return Changed;
+  }
----------------
rampitec wrote:
> madhur13490 wrote:
> > foad wrote:
> > > madhur13490 wrote:
> > > > arsenm wrote:
> > > > > Just assert, the return is dead
> > > > I'd say its a style choice. Preferring llvm_unreachable over assert.
> > > Then it's a bad choice :) I agree with Matt. `assert(CG)` or `assert(CG && "message")` are shorter and simpler and more familiar because they're already ubiquitous throughout llvm.
> > As per coding standards, llvm_unreachable seems more preferred.
> > https://llvm.org/docs/CodingStandards.html#assert-liberally
> > 
> > @rampitec What do you think? Internally, I changed this from assert.
> > 
> Internally if was "if() assert(false ...)". assert(false) shall never be used, that's why I suggested llvm_unreachange() instead. But "assert(ModuleCG);" is a more common thing.
There are ways to implement this:
A.
```
if (!ModuleCG) { 
   assert(false, "ModuleCG not present"); 
   return; 
} 
<rest code>
```
B. Just   
```
assert(ModuleCG && "Module CG not present"); 
< rest code>
```
C.

```
 if (!ModuleCG) { 
      llvm_unreachable("ModuleCG"); 
      return; 
 } 
<rest code>
```

Matt suggests B but in release builds the code would just crash because it would end up accessing nullptr.
I had A initially because it asserts as well as returns gracefully so it does not crash. C is similar to A just llvm_unreachable replaces assert.

I prefer but C because it follows coding standard and also returns gracefully returns in release builds.

Which one we agree the best here?


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D103138/new/

https://reviews.llvm.org/D103138