[PATCH] D102212: [AMDGPU] Add Optimize VGPR LiveRange Pass.

[Jay Foad via Phabricator via llvm-commits]

foad added inline comments.


================
Comment at: llvm/lib/Target/AMDGPU/SIOptimizeVGPRLiveRange.cpp:158
+
+    if (Cur < Blocks.size())
+      MBB = Blocks[Cur++];
----------------
critson wrote:
> This doesn't seem right.
> You only collect an arbitrary number of blocks?
> Should ElseBlocks not simply be growing to hold all relevant blocks?
Cur tells you the first index in Blocks of a block that you have *not* already visited to scan its predecessors. Perhaps it would be clearer as:
```
SetVector<MachineBasicBlock *> Blocks(Endif);
for (unsigned Cur = 0; Cur < Blocks.size(); ++Cur) {
  auto *MBB = Blocks[Cur];
  for (auto *Pred : MBB->predecessors()) {
    if (Pred != Flow)
      Blocks.insert(Pred);
  }
}
```


================
Comment at: llvm/lib/Target/AMDGPU/SIOptimizeVGPRLiveRange.cpp:174
+    SmallVectorImpl<MachineInstr *> &Uses) const {
+  for (auto I = MRI->use_nodbg_begin(Reg), E = MRI->use_nodbg_end(); I != E;
+       ++I) {
----------------
`for (auto &UseMI : MRI->use_nodbg_instructions(Reg))`


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  https://reviews.llvm.org/D102212/new/

https://reviews.llvm.org/D102212