While moving exit condition, do not drop loop latch on the floor.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47089 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Transforms/Scalar/LoopIndexSplit.cpp b/lib/Transforms/Scalar/LoopIndexSplit.cpp
index 2d30eb6ff56884f5c53cfed93ad9bcff6b9530cb..383415b228bf163b5088deb16d984cd7b33085b0 100644 (file)
--- a/lib/Transforms/Scalar/LoopIndexSplit.cpp
+++ b/lib/Transforms/Scalar/LoopIndexSplit.cpp
@@ -1579,17 +1579,22 @@ void LoopIndexSplit::moveExitCondition(BasicBlock *CondBB, BasicBlock *ActiveBB,
   // destination.
   BranchInst *ExitingBR = cast<BranchInst>(ExitingBB->getTerminator());
   ExitingBR->moveBefore(CurrentBR);
-  if (ExitingBR->getSuccessor(0) == ExitBB)
+  BasicBlock *OrigDestBB = NULL;
+  if (ExitingBR->getSuccessor(0) == ExitBB) {
+    OrigDestBB = ExitingBR->getSuccessor(1);
     ExitingBR->setSuccessor(1, ActiveBB);
-  else
+  }
+  else {
+    OrigDestBB = ExitingBR->getSuccessor(0);
     ExitingBR->setSuccessor(0, ActiveBB);
+  }
     
   // Remove split condition and current split condition branch.
   SC->eraseFromParent();
   CurrentBR->eraseFromParent();
 
-  // Connect exiting block to split condition block.
-  new BranchInst(CondBB, ExitingBB);
+  // Connect exiting block to original destination.
+  new BranchInst(OrigDestBB, ExitingBB);
 
   // Update PHINodes
   updatePHINodes(ExitBB, ExitingBB, CondBB, IV, IVAdd);

diff --git a/test/Transforms/LoopIndexSplit/2008-02-13-LoopLatch.ll b/test/Transforms/LoopIndexSplit/2008-02-13-LoopLatch.ll
new file mode 100644 (file)
index 0000000..0c67ea2
--- /dev/null
+++ b/test/Transforms/LoopIndexSplit/2008-02-13-LoopLatch.ll
@@ -0,0 +1,72 @@
+; RUN: llvm-as < %s | opt -loop-index-split -disable-output
+; PR 2011
+       %struct.CLAUSE_HELP = type { i32, i32, i32, i32, i32*, i32, %struct.LIST_NODE*, %struct.LIST_NODE*, i32, i32, %struct.LITERAL_HELP**, i32, i32, i32, i32 }
+       %struct.LIST_NODE = type { %struct.LIST_NODE*, i8* }
+       %struct.LITERAL_HELP = type { i32, i32, i32, %struct.CLAUSE_HELP*, %struct.term* }
+       %struct.anon = type { %struct.LIST_NODE* }
+       %struct.st = type { %struct.subst*, %struct.LIST_NODE*, %struct.LIST_NODE*, i16, i16 }
+       %struct.subst = type { %struct.subst*, i32, %struct.term* }
+       %struct.term = type { i32, %struct.anon, %struct.LIST_NODE*, i32, i32 }
+
+define fastcc %struct.LIST_NODE* @inf_HyperResolvents(%struct.CLAUSE_HELP* %Clause, %struct.subst* %Subst, %struct.LIST_NODE* %Restlits, i32 %GlobalMaxVar, %struct.LIST_NODE* %FoundMap, i32 %StrictlyMaximal, { %struct.st*, [3001 x %struct.term*], [4000 x %struct.term*], i32 }* %Index, i32* %Flags, i32* %Precedence) nounwind  {
+entry:
+       br i1 false, label %bb960, label %bb885
+
+bb885:         ; preds = %entry
+       ret %struct.LIST_NODE* null
+
+bb960:         ; preds = %entry
+       br i1 false, label %bb1097, label %bb1005.preheader
+
+bb1005.preheader:              ; preds = %bb960
+       ret %struct.LIST_NODE* null
+
+bb1097:                ; preds = %bb960
+       br i1 false, label %bb1269.preheader, label %bb1141.preheader
+
+bb1141.preheader:              ; preds = %bb1097
+       ret %struct.LIST_NODE* null
+
+bb1269.preheader:              ; preds = %bb1097
+       br i1 false, label %bb1318, label %bb1281
+
+bb1281:                ; preds = %bb1269.preheader
+       ret %struct.LIST_NODE* null
+
+bb1318:                ; preds = %bb1269.preheader
+       br i1 false, label %bb1459, label %bb.nph52
+
+bb.nph52:              ; preds = %bb1318
+       ret %struct.LIST_NODE* null
+
+bb1459:                ; preds = %bb1318
+       br i1 false, label %bb1553, label %bb.nph62
+
+bb.nph62:              ; preds = %bb1459
+       ret %struct.LIST_NODE* null
+
+bb1553:                ; preds = %bb1669, %bb1459
+       %j295.0.reg2mem.0 = phi i32 [ %storemerge110, %bb1669 ], [ 0, %bb1459 ]         ; <i32> [#uses=2]
+       br i1 false, label %bb1588, label %bb1616
+
+bb1588:                ; preds = %bb1553
+       br label %bb1616
+
+bb1616:                ; preds = %bb1588, %bb1553
+       %tmp1629 = icmp sgt i32 %j295.0.reg2mem.0, 0            ; <i1> [#uses=1]
+       br i1 %tmp1629, label %bb1649, label %bb1632
+
+bb1632:                ; preds = %bb1616
+       br label %bb1669
+
+bb1649:                ; preds = %bb1616
+       br label %bb1669
+
+bb1669:                ; preds = %bb1649, %bb1632
+       %storemerge110 = add i32 %j295.0.reg2mem.0, 1           ; <i32> [#uses=2]
+       %tmp1672 = icmp sgt i32 %storemerge110, 0               ; <i1> [#uses=1]
+       br i1 %tmp1672, label %bb1678, label %bb1553
+
+bb1678:                ; preds = %bb1669
+       ret %struct.LIST_NODE* null
+}