Index: llvm/trunk/lib/Transforms/Scalar/JumpThreading.cpp
===================================================================
--- llvm/trunk/lib/Transforms/Scalar/JumpThreading.cpp
+++ llvm/trunk/lib/Transforms/Scalar/JumpThreading.cpp
@@ -102,6 +102,12 @@
     cl::desc("Print the LazyValueInfo cache after JumpThreading"), cl::init(false),
     cl::Hidden);
 
+static cl::opt<bool> ThreadAcrossLoopHeaders(
+    "jump-threading-across-loop-headers",
+    cl::desc("Allow JumpThreading to thread across loop headers, for testing"),
+    cl::init(false), cl::Hidden);
+
+
 namespace {
 
   /// This pass performs 'jump threading', which looks at blocks that have
@@ -368,7 +374,8 @@
     if (!DT.isReachableFromEntry(&BB))
       Unreachable.insert(&BB);
 
-  FindLoopHeaders(F);
+  if (!ThreadAcrossLoopHeaders)
+    FindLoopHeaders(F);
 
   bool EverChanged = false;
   bool Changed;
@@ -1978,8 +1985,14 @@
   }
 
   BasicBlock::iterator BI = BB->begin();
-  for (; PHINode *PN = dyn_cast<PHINode>(BI); ++BI)
-    ValueMapping[PN] = PN->getIncomingValueForBlock(PredBB);
+  // Clone the phi nodes of BB into NewBB. The resulting phi nodes are trivial,
+  // since NewBB only has one predecessor, but SSAUpdater might need to rewrite
+  // the operand of the cloned phi.
+  for (; PHINode *PN = dyn_cast<PHINode>(BI); ++BI) {
+    PHINode *NewPN = PHINode::Create(PN->getType(), 1, PN->getName(), NewBB);
+    NewPN->addIncoming(PN->getIncomingValueForBlock(PredBB), PredBB);
+    ValueMapping[PN] = NewPN;
+  }
 
   // Clone the non-phi instructions of BB into NewBB, keeping track of the
   // mapping and using it to remap operands in the cloned instructions.
Index: llvm/trunk/test/Transforms/JumpThreading/loop-phi.ll
===================================================================
--- llvm/trunk/test/Transforms/JumpThreading/loop-phi.ll
+++ llvm/trunk/test/Transforms/JumpThreading/loop-phi.ll
@@ -0,0 +1,41 @@
+; RUN: opt < %s -jump-threading -S -jump-threading-across-loop-headers | FileCheck %s
+
+; Make sure we correctly distinguish between %tmp15 and %tmp16 when we clone
+; body2.
+
+; CHECK:      body2.thread:
+; CHECK-NEXT: %tmp163 = add i32 %tmp165, 1
+; CHECK-NEXT: br label %latch1
+
+; CHECK:      latch1:
+; CHECK-NEXT: %tmp165 = phi i32 [ %tmp163, %body2.thread ], [ %tmp16, %body2 ]
+; CHECK-NEXT: %tmp154 = phi i32 [ %tmp165, %body2.thread ], [ %tmp15, %body2 ]
+
+define i32 @test(i1 %ARG1, i1 %ARG2, i32 %n) {
+entry:
+  br label %head1
+
+head1:                                            ; preds = %entry, %body1
+  %tmp = phi i32 [ 0, %entry ], [ %tmp16, %body1 ]
+  %tmp3 = phi i32 [ 0, %entry ], [ %tmp16, %body1 ]
+  %tmp4 = phi i32 [ 0, %entry ], [ %tmp16, %body1 ]
+  br i1 %ARG1, label %exit, label %body2
+
+body1:                                            ; preds = %latch1
+  %tmp12 = icmp sgt i32 %tmp16, 1
+  br i1 %tmp12, label %body2, label %head1
+
+body2:                                            ; preds = %head1, %body1
+  %tmp14 = phi i32 [ %tmp16, %body1 ], [ %tmp, %head1 ]
+  %tmp15 = phi i32 [ %tmp16, %body1 ], [ %tmp3, %head1 ]
+  %tmp16 = add i32 %tmp14, 1
+  br i1 %ARG2, label %exit, label %latch1
+
+latch1:                                           ; preds = %body2
+  %tmp18 = icmp sgt i32 %tmp16, %n
+  br i1 %tmp18, label %exit, label %body1
+
+exit:                                             ; preds = %latch1, %body2, %head1
+  %rc = phi i32 [ %tmp15, %body2 ], [ %tmp15, %latch1 ], [ -1, %head1 ]
+  ret i32 %rc
+}
Index: llvm/trunk/test/Transforms/JumpThreading/lvi-tristate.ll
===================================================================
--- llvm/trunk/test/Transforms/JumpThreading/lvi-tristate.ll
+++ llvm/trunk/test/Transforms/JumpThreading/lvi-tristate.ll
@@ -1,17 +1,19 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
 ; RUN: opt -jump-threading -simplifycfg -S < %s | FileCheck %s
-; CHECK-NOT: bb6:
-; CHECK-NOT: bb7:
-; CHECK-NOT: bb8:
-; CHECK-NOT: bb11:
-; CHECK-NOT: bb12:
-; CHECK: bb:
-; CHECK: bb2:
-; CHECK: bb4:
-; CHECK: bb10:
-; CHECK: bb13:
 declare void @ham()
 
 define void @hoge() {
+; CHECK-LABEL: @hoge(
+; CHECK-NEXT:  bb:
+; CHECK-NEXT:    [[TMP:%.*]] = and i32 undef, 1073741823
+; CHECK-NEXT:    [[COND:%.*]] = icmp eq i32 [[TMP]], 5
+; CHECK-NEXT:    br i1 [[COND]], label [[BB10:%.*]], label [[BB13:%.*]]
+; CHECK:       bb10:
+; CHECK-NEXT:    tail call void @ham()
+; CHECK-NEXT:    br label [[BB13]]
+; CHECK:       bb13:
+; CHECK-NEXT:    ret void
+;
 bb:
   %tmp = and i32 undef, 1073741823
   %tmp1 = icmp eq i32 %tmp, 2
Index: llvm/trunk/test/Transforms/JumpThreading/select.ll
===================================================================
--- llvm/trunk/test/Transforms/JumpThreading/select.ll
+++ llvm/trunk/test/Transforms/JumpThreading/select.ll
@@ -281,12 +281,12 @@
   ret i32 %j.add3
 
 ; CHECK-LABEL: @unfold3
-; CHECK: br i1 %cmp.i, label %.exit.thread2, label %cond.false.i
+; CHECK: br i1 %cmp.i, label %.exit.thread3, label %cond.false.i
 ; CHECK: br i1 %cmp4.i, label %.exit.thread, label %cond.false.6.i
-; CHECK: br i1 %cmp8.i, label %.exit.thread2, label %cond.false.10.i
+; CHECK: br i1 %cmp8.i, label %.exit.thread3, label %cond.false.10.i
 ; CHECK: br i1 %cmp13.i, label %.exit.thread, label %.exit
-; CHECK: br i1 %phitmp, label %.exit.thread, label %.exit.thread2
-; CHECK: br label %.exit.thread2
+; CHECK: br i1 %phitmp, label %.exit.thread, label %.exit.thread3
+; CHECK: br label %.exit.thread3
 }
 
 define i32 @unfold4(i32 %u, i32 %v, i32 %w, i32 %x, i32 %y, i32 %z, i32 %j) nounwind {
@@ -320,11 +320,11 @@
 
 ; CHECK-LABEL: @unfold4
 ; CHECK: br i1 %cmp.i, label %.exit.thread, label %cond.false.i
-; CHECK: br i1 %cmp4.i, label %.exit.thread3, label %cond.false.6.i
+; CHECK: br i1 %cmp4.i, label %.exit.thread4, label %cond.false.6.i
 ; CHECK: br i1 %cmp8.i, label %.exit.thread, label %cond.false.10.i
-; CHECK: br i1 %cmp13.i, label %.exit.thread3, label %.exit
-; CHECK: br i1 %lnot.i18, label %.exit.thread, label %.exit.thread3
-; CHECK: br label %.exit.thread3
+; CHECK: br i1 %cmp13.i, label %.exit.thread4, label %.exit
+; CHECK: br i1 %lnot.i18, label %.exit.thread, label %.exit.thread4
+; CHECK: br label %.exit.thread4
 }
 
 define i32 @unfold5(i32 %u, i32 %v, i32 %w, i32 %x, i32 %y, i32 %z, i32 %j) nounwind {
Index: llvm/trunk/test/Transforms/JumpThreading/thread-loads.ll
===================================================================
--- llvm/trunk/test/Transforms/JumpThreading/thread-loads.ll
+++ llvm/trunk/test/Transforms/JumpThreading/thread-loads.ll
@@ -32,8 +32,8 @@
 
 bb3:		; preds = %bb1
 ; CHECK: bb3:
-; CHECK: %res.01 = phi i32 [ 1, %bb1.thread ], [ 0, %bb1 ]
-; CHECK: ret i32 %res.01
+; CHECK: %res.02 = phi i32 [ 1, %bb1.thread ], [ 0, %bb1 ]
+; CHECK: ret i32 %res.02
 	ret i32 %res.0
 }
 
@@ -71,8 +71,8 @@
 
 bb3:		; preds = %bb1
 ; CHECK: bb3:
-; CHECK: %res.01 = phi i32 [ 1, %bb1.thread ], [ 0, %bb1 ]
-; CHECK: ret i32 %res.01
+; CHECK: %res.02 = phi i32 [ 1, %bb1.thread ], [ 0, %bb1 ]
+; CHECK: ret i32 %res.02
 	ret i32 %res.0
 }