[PATCH] D69661: [AMDGPU] Fix vccz after v_readlane/v_readfirstlane to vcc_lo/hi

[Matt Arsenault via Phabricator via llvm-commits]

arsenm added inline comments.


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Comment at: llvm/lib/Target/AMDGPU/SIInsertWaitcnts.cpp:1406
+
+    if (ST->getGeneration() <= AMDGPUSubtarget::GFX9) {
+      // Up to gfx9, writes to vcc_lo and vcc_hi don't update vccz.
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I thought we already had a vccz bug subtarget feature check? Either way I want to limit getGeneration checks and keep them in a subtarget check


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Comment at: llvm/lib/Target/AMDGPU/SIInsertWaitcnts.cpp:1409
+      // Writes to vcc will fix it. Only examine explicit defs.
+      for (auto &Op : Inst.defs()) {
+        switch (Op.getReg()) {
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This won't catch the implicit def in inline asm for example


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D69661/new/

https://reviews.llvm.org/D69661