[NFC][SYCL] Minor stylistic changes in SYCLPropagateAspectsUsage.cpp

[aelovikov-intel]

No description provided.

[aelovikov-intel]

I also think that https://github.com/intel/llvm/pull/7049/files#diff-68d289383a30446b6ac4a16059d3b19708674ac2562fa5ddb8af87fb5158e9cdL273-L275 should be re-written using depth_first (or similar) iterators to avoid manual Visited set tracking. Should be another PR though.

[AlexeySachkov]

I also think that https://github.com/intel/llvm/pull/7049/files#diff-68d289383a30446b6ac4a16059d3b19708674ac2562fa5ddb8af87fb5158e9cdL273-L275 should be re-written using depth_first (or similar) iterators to avoid manual Visited set tracking

Do I understand correctly that a suggestion here is to switch to some existing call graph handling data structure (perhaps llvm::CallGraph?), which will do Visited tracking for us under the hood, thus simplifying the pass code?

[AlexeySachkov]

Good to know that such helpers exist, thanks!

[aelovikov-intel]

Do I understand correctly that a suggestion here is to switch to some existing call graph handling data structure (perhaps llvm::CallGraph?), which will do Visited tracking for us under the hood, thus simplifying the pass code?

I didn't have a deep look (and I still need to address CI failures for this version before starting any other refactoring), but I'd expect the answer is "not quite". I think we'd have the same data structure but the code traversing it would be different. Instead of the Visited set and manual recursion we'll create graph traits specialization and then use it to start llvm::depth_first traversal. It would look somewhat like this (pseudocode):

template <>
struct GraphTraits<CallGraphNode> {
// immediate children iterators.
};

CallGraph CG{...};
for (Function &F : depth_first(CG->getRootNode)) {
   // Process F.
}

[aelovikov-intel]

The same ESIMD EMU failures:

Failed Tests (2):
SYCL :: dword_atomic_smoke.cpp
SYCL :: lsc/lsc_fence.cpp

are seen on another PR hence unrelated to this one.

[asudarsa]

LGTM. Nice change to showcase good coding practices. Thanks