[PATCH] D73771: [AMDGPU] Don't remove short branches over kills

[Jay Foad via Phabricator via llvm-commits]

foad created this revision.
foad added reviewers: critson, arsenm, nhaehnle, cdevadas, hakzsam.
Herald added subscribers: kerbowa, hiraditya, t-tye, tpr, dstuttard, yaxunl, wdng, jvesely, kzhuravl.
Herald added a project: LLVM.

D68092 <https://reviews.llvm.org/D68092> introduced a new SIRemoveShortExecBranches optimization pass and
broke some graphics shaders. The problem is that it was removing
branches over KILL pseudo instructions, and the fix is to explicitly
check for that in mustRetainExeczBranch.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D73771

Files:
  llvm/lib/Target/AMDGPU/SIRemoveShortExecBranches.cpp


Index: llvm/lib/Target/AMDGPU/SIRemoveShortExecBranches.cpp
===================================================================
--- llvm/lib/Target/AMDGPU/SIRemoveShortExecBranches.cpp
+++ llvm/lib/Target/AMDGPU/SIRemoveShortExecBranches.cpp
@@ -96,6 +96,9 @@
       if (TII->hasUnwantedEffectsWhenEXECEmpty(*I))
         return true;
 
+      if (TII->isKillTerminator(I->getOpcode()))
+        return true;
+
       // These instructions are potentially expensive even if EXEC = 0.
       if (TII->isSMRD(*I) || TII->isVMEM(*I) || TII->isFLAT(*I) ||
           I->getOpcode() == AMDGPU::S_WAITCNT)


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