[PATCH] D81433: AMDGPU: Restrict the number of instructions to scan for getPointerDependencyFrom

[Changpeng Fang via Phabricator via llvm-commits]

cfang marked an inline comment as done.
cfang added inline comments.


================
Comment at: llvm/lib/Target/AMDGPU/AMDGPUAnnotateUniformValues.cpp:109
+  // Maximum number of instructions to search in a block (default 100).
+  auto Limit = MDR->getDefaultBlockScanLimit();
   for (auto &BB : Checklist) {
----------------
arsenm wrote:
> I don't see how this changes anything. This is what the default null case does?
> 
>   unsigned DefaultLimit = getDefaultBlockScanLimit();
>   if (!Limit)
>     Limit = &DefaultLimit;
> 
Ooh, the change is even not correct due to the weird design of the Limit usage:
    --*Limit;
    if (!*Limit)
      return MemDepResult::getUnknown();

This will usually causes trouble if you don't use default nullptr. You will have to set the Limit before each call.

To say that, the use at DeadStoreElimination.cpp is also not correct.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D81433/new/

https://reviews.llvm.org/D81433