[PATCH] D110700: [LiveVariables] Skip verification of kills inside bundles

[Jay Foad via Phabricator via llvm-commits]

foad created this revision.
foad added reviewers: efriedma, MatzeB, qcolombet, stoklund.
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LiveVariables does not examine the contents of bundles, so
MachineVerifier should not expect it to know about kill flags on
operands of instructions inside a bundle.

With this fix we can enable machine verification after running the
LiveVariables analysis. Doing this does not show any problems in
check-llvm in an LLVM_ENABLE_EXPENSIVE_CHECKS build.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D110700

Files:
  llvm/lib/CodeGen/MachineVerifier.cpp
  llvm/lib/CodeGen/TargetPassConfig.cpp


Index: llvm/lib/CodeGen/TargetPassConfig.cpp
===================================================================
--- llvm/lib/CodeGen/TargetPassConfig.cpp
+++ llvm/lib/CodeGen/TargetPassConfig.cpp
@@ -1442,7 +1442,7 @@
   // Explicit addition of UnreachableMachineBlockElim allows stopping before or
   // after it with -stop-before/-stop-after.
   addPass(&UnreachableMachineBlockElimID);
-  addPass(&LiveVariablesID, false);
+  addPass(&LiveVariablesID);
 
   // Edge splitting is smarter with machine loop info.
   addPass(&MachineLoopInfoID, false);
Index: llvm/lib/CodeGen/MachineVerifier.cpp
===================================================================
--- llvm/lib/CodeGen/MachineVerifier.cpp
+++ llvm/lib/CodeGen/MachineVerifier.cpp
@@ -2211,8 +2211,11 @@
     if (MO->isKill())
       addRegWithSubRegs(regsKilled, Reg);
 
-    // Check that LiveVars knows this kill.
-    if (LiveVars && Register::isVirtualRegister(Reg) && MO->isKill()) {
+    // Check that LiveVars knows this kill (unless we are inside a bundle, in
+    // which case we have already checked that LiveVars knows any kills on the
+    // bundle header instead).
+    if (LiveVars && Register::isVirtualRegister(Reg) && MO->isKill() &&
+        !MI->isBundledWithPred()) {
       LiveVariables::VarInfo &VI = LiveVars->getVarInfo(Reg);
       if (!is_contained(VI.Kills, MI))
         report("Kill missing from LiveVariables", MO, MONum);


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