vendor/llvm-project/llvmorg-12-init-17869-g8e464dd76bef

1 files changed, 16 insertions, 12 deletions

diff --git a/llvm/lib/Transforms/Scalar/LoopSimplifyCFG.cpp b/llvm/lib/Transforms/Scalar/LoopSimplifyCFG.cpp
index 031e5b9c1d2c..cc6d11220807 100644
--- a/llvm/lib/Transforms/Scalar/LoopSimplifyCFG.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopSimplifyCFG.cpp
@@ -16,7 +16,6 @@
 #include "llvm/Transforms/Scalar/LoopSimplifyCFG.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/Statistic.h"
-#include "llvm/Analysis/AliasAnalysis.h"
 #include "llvm/Analysis/AssumptionCache.h"
 #include "llvm/Analysis/BasicAliasAnalysis.h"
 #include "llvm/Analysis/DependenceAnalysis.h"
@@ -366,15 +365,20 @@ private:
 
     unsigned DummyIdx = 1;
     for (BasicBlock *BB : DeadExitBlocks) {
-      SmallVector<Instruction *, 4> DeadPhis;
+      // Eliminate all Phis and LandingPads from dead exits.
+      // TODO: Consider removing all instructions in this dead block.
+      SmallVector<Instruction *, 4> DeadInstructions;
       for (auto &PN : BB->phis())
-        DeadPhis.push_back(&PN);
+        DeadInstructions.push_back(&PN);
 
-      // Eliminate all Phis from dead exits.
-      for (Instruction *PN : DeadPhis) {
-        PN->replaceAllUsesWith(UndefValue::get(PN->getType()));
-        PN->eraseFromParent();
+      if (auto *LandingPad = dyn_cast<LandingPadInst>(BB->getFirstNonPHI()))
+        DeadInstructions.emplace_back(LandingPad);
+
+      for (Instruction *I : DeadInstructions) {
+        I->replaceAllUsesWith(UndefValue::get(I->getType()));
+        I->eraseFromParent();
       }
+
       assert(DummyIdx != 0 && "Too many dead exits!");
       DummySwitch->addCase(Builder.getInt32(DummyIdx++), BB);
       DTUpdates.push_back({DominatorTree::Insert, Preheader, BB});
@@ -410,9 +414,10 @@ private:
           FixLCSSALoop = FixLCSSALoop->getParentLoop();
         assert(FixLCSSALoop && "Should be a loop!");
         // We need all DT updates to be done before forming LCSSA.
-        DTU.applyUpdates(DTUpdates);
         if (MSSAU)
-          MSSAU->applyUpdates(DTUpdates, DT);
+          MSSAU->applyUpdates(DTUpdates, DT, /*UpdateDT=*/true);
+        else
+          DTU.applyUpdates(DTUpdates);
         DTUpdates.clear();
         formLCSSARecursively(*FixLCSSALoop, DT, &LI, &SE);
       }
@@ -420,8 +425,7 @@ private:
 
     if (MSSAU) {
       // Clear all updates now. Facilitates deletes that follow.
-      DTU.applyUpdates(DTUpdates);
-      MSSAU->applyUpdates(DTUpdates, DT);
+      MSSAU->applyUpdates(DTUpdates, DT, /*UpdateDT=*/true);
       DTUpdates.clear();
       if (VerifyMemorySSA)
         MSSAU->getMemorySSA()->verifyMemorySSA();
@@ -447,7 +451,7 @@ private:
       if (LI.isLoopHeader(BB)) {
         assert(LI.getLoopFor(BB) != &L && "Attempt to remove current loop!");
         Loop *DL = LI.getLoopFor(BB);
-        if (DL->getParentLoop()) {
+        if (!DL->isOutermost()) {
           for (auto *PL = DL->getParentLoop(); PL; PL = PL->getParentLoop())
             for (auto *BB : DL->getBlocks())
               PL->removeBlockFromLoop(BB);