Revert "Revert r330403 and r330413."

Reapply the patches with a fix. Thanks Ilya and Hans for the reproducer!
This reverts commit r330416.

The issue was that removing predecessors invalidated uses that we stored
for rewrite. The fix is to finish manipulating with CFG before we select
uses for rewrite.

llvm-svn: 330431

1 files changed, 20 insertions, 20 deletions

diff --git a/llvm/unittests/Transforms/Utils/SSAUpdaterBulk.cpp b/llvm/unittests/Transforms/Utils/SSAUpdaterBulk.cpp
index 6a8adf9ef37..61cbcb7b1a7 100644
--- a/llvm/unittests/Transforms/Utils/SSAUpdaterBulk.cpp
+++ b/llvm/unittests/Transforms/Utils/SSAUpdaterBulk.cpp
@@ -73,17 +73,17 @@ TEST(SSAUpdaterBulk, SimpleMerge) {
   // SSAUpdater should insert into %merge.
   // Intentionally don't touch %8 to see that SSAUpdater only changes
   // instructions that were explicitly specified.
-  Updater.AddVariable(0, "a", I32Ty);
-  Updater.AddAvailableValue(0, TrueBB, AddOp1);
-  Updater.AddAvailableValue(0, FalseBB, AddOp2);
-  Updater.AddUse(0, &I1->getOperandUse(0));
-  Updater.AddUse(0, &I2->getOperandUse(0));
-
-  Updater.AddVariable(1, "b", I32Ty);
-  Updater.AddAvailableValue(1, TrueBB, SubOp1);
-  Updater.AddAvailableValue(1, FalseBB, SubOp2);
-  Updater.AddUse(1, &I3->getOperandUse(0));
-  Updater.AddUse(1, &I3->getOperandUse(1));
+  unsigned VarNum = Updater.AddVariable("a", I32Ty);
+  Updater.AddAvailableValue(VarNum, TrueBB, AddOp1);
+  Updater.AddAvailableValue(VarNum, FalseBB, AddOp2);
+  Updater.AddUse(VarNum, &I1->getOperandUse(0));
+  Updater.AddUse(VarNum, &I2->getOperandUse(0));
+
+  VarNum = Updater.AddVariable("b", I32Ty);
+  Updater.AddAvailableValue(VarNum, TrueBB, SubOp1);
+  Updater.AddAvailableValue(VarNum, FalseBB, SubOp2);
+  Updater.AddUse(VarNum, &I3->getOperandUse(0));
+  Updater.AddUse(VarNum, &I3->getOperandUse(1));
 
   DominatorTree DT(*F);
   Updater.RewriteAllUses(&DT);
@@ -161,19 +161,19 @@ TEST(SSAUpdaterBulk, Irreducible) {
   // No other rewrites should be made.
 
   // Add use in %3.
-  Updater.AddVariable(0, "c", I32Ty);
-  Updater.AddAvailableValue(0, IfBB, AddOp1);
-  Updater.AddUse(0, &I1->getOperandUse(0));
+  unsigned VarNum = Updater.AddVariable("c", I32Ty);
+  Updater.AddAvailableValue(VarNum, IfBB, AddOp1);
+  Updater.AddUse(VarNum, &I1->getOperandUse(0));
 
   // Add use in %4.
-  Updater.AddVariable(1, "b", I32Ty);
-  Updater.AddAvailableValue(1, LoopStartBB, AddOp2);
-  Updater.AddUse(1, &I2->getOperandUse(0));
+  VarNum = Updater.AddVariable("b", I32Ty);
+  Updater.AddAvailableValue(VarNum, LoopStartBB, AddOp2);
+  Updater.AddUse(VarNum, &I2->getOperandUse(0));
 
   // Add use in the return instruction.
-  Updater.AddVariable(2, "a", I32Ty);
-  Updater.AddAvailableValue(2, &F->getEntryBlock(), FirstArg);
-  Updater.AddUse(2, &Return->getOperandUse(0));
+  VarNum = Updater.AddVariable("a", I32Ty);
+  Updater.AddAvailableValue(VarNum, &F->getEntryBlock(), FirstArg);
+  Updater.AddUse(VarNum, &Return->getOperandUse(0));
 
   // Save all inserted phis into a vector.
   SmallVector<PHINode *, 8> Inserted;