My last commit was not correct for nested loops. Fix it, and add a testcase for it.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@40498 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Transforms/Scalar/GVN.cpp b/lib/Transforms/Scalar/GVN.cpp
index eb12abe243c906ecf8ab20541aa411aa1ad8d603..f3aa7960f66a3b87c0c51347ee72bac24ed099da 100644 (file)
--- a/lib/Transforms/Scalar/GVN.cpp
+++ b/lib/Transforms/Scalar/GVN.cpp
@@ -731,6 +731,7 @@ Value *GVN::performPHIConstruction(BasicBlock *BB, LoadInst* orig,
   } else {
     PHINode *PN = new PHINode(orig->getType(), orig->getName()+".rle", BB->begin());
     PN->reserveOperandSpace(numPreds);
+    Phis[BB] = PN;
     
     visited.insert(BB);
     // Fill in the incoming values for the block.
@@ -738,7 +739,7 @@ Value *GVN::performPHIConstruction(BasicBlock *BB, LoadInst* orig,
       if (!visited.count(*PI))
         PN->addIncoming(performPHIConstruction(*PI, orig, Phis, visited), *PI);
       else
-        PN->addIncoming(PN, *PI);
+        PN->addIncoming(Phis[*PI], *PI);
     visited.erase(BB);
     
     bool all_same = PN->getNumIncomingValues() != 1;
@@ -748,6 +749,7 @@ Value *GVN::performPHIConstruction(BasicBlock *BB, LoadInst* orig,
     
     if (all_same) {
       PN->eraseFromParent();
+      Phis[BB] = first;
       return first;
     } else {
       return PN;

diff --git a/test/Transforms/GVN/2007-07-25-NestedLoop.ll b/test/Transforms/GVN/2007-07-25-NestedLoop.ll
new file mode 100644 (file)
index 0000000..cebaaa3
--- /dev/null
+++ b/test/Transforms/GVN/2007-07-25-NestedLoop.ll
@@ -0,0 +1,38 @@
+; RUN: llvm-as < %s | opt -gvn | llvm-dis
+
+       %struct.TypHeader = type { i32, %struct.TypHeader**, [3 x i8], i8 }
+
+define %struct.TypHeader* @LtRec(%struct.TypHeader* %hdL, %struct.TypHeader* %hdR) {
+entry:
+       br i1 false, label %bb556.preheader, label %bb534.preheader
+
+bb534.preheader:               ; preds = %entry
+       ret %struct.TypHeader* null
+
+bb556.preheader:               ; preds = %entry
+       %tmp56119 = getelementptr %struct.TypHeader* %hdR, i32 0, i32 0         ; <i32*> [#uses=1]
+       %tmp56220 = load i32* %tmp56119         ; <i32> [#uses=0]
+       br i1 false, label %bb.nph23, label %bb675.preheader
+
+bb.nph23:              ; preds = %bb556.preheader
+       ret %struct.TypHeader* null
+
+bb656:         ; preds = %bb675.outer, %bb656
+       %tmp678 = load i32* %tmp677             ; <i32> [#uses=0]
+       br i1 false, label %bb684, label %bb656
+
+bb684:         ; preds = %bb675.outer, %bb656
+       br i1 false, label %bb924.preheader, label %bb675.outer
+
+bb675.outer:           ; preds = %bb675.preheader, %bb684
+       %tmp67812 = load i32* %tmp67711         ; <i32> [#uses=0]
+       br i1 false, label %bb684, label %bb656
+
+bb675.preheader:               ; preds = %bb556.preheader
+       %tmp67711 = getelementptr %struct.TypHeader* %hdR, i32 0, i32 0         ; <i32*> [#uses=1]
+       %tmp677 = getelementptr %struct.TypHeader* %hdR, i32 0, i32 0           ; <i32*> [#uses=1]
+       br label %bb675.outer
+
+bb924.preheader:               ; preds = %bb684
+       ret %struct.TypHeader* null
+}