Index: lib/Target/PowerPC/PPCCTRLoops.cpp
===================================================================
--- lib/Target/PowerPC/PPCCTRLoops.cpp
+++ lib/Target/PowerPC/PPCCTRLoops.cpp
@@ -528,6 +528,30 @@
   SmallVector<BasicBlock*, 4> ExitingBlocks;
   L->getExitingBlocks(ExitingBlocks);
 
+  // If there is an exit edge known to be frequently taken,
+  // we should not transform this loop.
+  for (SmallVectorImpl<BasicBlock *>::iterator I = ExitingBlocks.begin(),
+       IE = ExitingBlocks.end(); I != IE; ++I) {
+    Instruction *TI = (*I)->getTerminator();
+    if (!TI) continue;
+
+    if (BranchInst *BI = dyn_cast<BranchInst>(TI)) {
+      uint64_t TrueWeight, FalseWeight;
+      if (!BI->isConditional() ||
+          !BI->extractProfMetadata(TrueWeight, FalseWeight))
+        continue;
+
+      BasicBlock *TrueBB = BI->getSuccessor(0);
+      uint64_t ExitWeight = L->contains(TrueBB) ? FalseWeight : TrueWeight;
+      BranchProbability BP = BranchProbability(ExitWeight,
+                                               TrueWeight + FalseWeight);
+      // If the exit path is more frequent than the loop path,
+      // we return here without further analysis for this loop.
+      if (BP > BranchProbability(1, 2))
+        return MadeChange;
+    }
+  }
+
   BasicBlock *CountedExitBlock = nullptr;
   const SCEV *ExitCount = nullptr;
   BranchInst *CountedExitBranch = nullptr;
Index: test/CodeGen/PowerPC/ctrloops-hot-exit.ll
===================================================================
--- /dev/null
+++ test/CodeGen/PowerPC/ctrloops-hot-exit.ll
@@ -0,0 +1,97 @@
+; RUN: llc -verify-machineinstrs -mtriple=powerpc64le-unknown-linux-gnu -mcpu=pwr9 < %s | FileCheck %s
+
+; If there is an exit edge known to be frequently taken,
+; we should not transform this loop.
+
+; A loop having a hot exit edge
+define signext i64 @func() {
+; CHECK: @func
+; CHECK-NOT: mtctr
+; CHECK-NOT: bdnz
+
+entry:
+  %a = alloca [1000 x i32], align 4
+  %0 = bitcast [1000 x i32]* %a to i8*
+  br label %for.body
+
+for.body:
+  %i.013 = phi i64 [ 0, %entry ], [ %inc, %if.end ]
+  %b.012 = phi i64 [ 0, %entry ], [ %xor, %if.end ]
+  %arrayidx = getelementptr inbounds [1000 x i32], [1000 x i32]* %a, i64 0, i64 %i.013
+  %1 = load i32, i32* %arrayidx, align 4
+  %tobool = icmp eq i32 %1, 0
+  br i1 %tobool, label %if.end, label %cleanup, !prof !1
+
+if.end:
+  %xor = xor i64 %i.013, %b.012
+  %inc = add nuw nsw i64 %i.013, 1
+  %cmp = icmp ult i64 %inc, 1000
+  br i1 %cmp, label %for.body, label %cleanup
+
+cleanup:
+  %res = phi i64 [ %b.012, %for.body ], [ %xor, %if.end ]
+  ret i64 %res
+}
+
+; A loop having a cold exit edge
+define signext i64 @func2() {
+; CHECK: @func2
+; CHECK: mtctr
+; CHECK: bdnz
+
+entry:
+  %a = alloca [1000 x i32], align 4
+  %0 = bitcast [1000 x i32]* %a to i8*
+  br label %for.body
+
+for.body:
+  %i.013 = phi i64 [ 0, %entry ], [ %inc, %if.end ]
+  %b.012 = phi i64 [ 0, %entry ], [ %xor, %if.end ]
+  %arrayidx = getelementptr inbounds [1000 x i32], [1000 x i32]* %a, i64 0, i64 %i.013
+  %1 = load i32, i32* %arrayidx, align 4
+  %tobool = icmp eq i32 %1, 0
+  br i1 %tobool, label %if.end, label %cleanup, !prof !2
+
+if.end:
+  %xor = xor i64 %i.013, %b.012
+  %inc = add nuw nsw i64 %i.013, 1
+  %cmp = icmp ult i64 %inc, 1000
+  br i1 %cmp, label %for.body, label %cleanup
+
+cleanup:
+  %res = phi i64 [ %b.012, %for.body ], [ %xor, %if.end ]
+  ret i64 %res
+}
+
+; A loop having an exit edge without profile data
+define signext i64 @func3() {
+; CHECK: @func3
+; CHECK: mtctr
+; CHECK: bdnz
+
+entry:
+  %a = alloca [1000 x i32], align 4
+  %0 = bitcast [1000 x i32]* %a to i8*
+  br label %for.body
+
+for.body:
+  %i.013 = phi i64 [ 0, %entry ], [ %inc, %if.end ]
+  %b.012 = phi i64 [ 0, %entry ], [ %xor, %if.end ]
+  %arrayidx = getelementptr inbounds [1000 x i32], [1000 x i32]* %a, i64 0, i64 %i.013
+  %1 = load i32, i32* %arrayidx, align 4
+  %tobool = icmp eq i32 %1, 0
+  br i1 %tobool, label %if.end, label %cleanup
+
+if.end:
+  %xor = xor i64 %i.013, %b.012
+  %inc = add nuw nsw i64 %i.013, 1
+  %cmp = icmp ult i64 %inc, 1000
+  br i1 %cmp, label %for.body, label %cleanup
+
+cleanup:
+  %res = phi i64 [ %b.012, %for.body ], [ %xor, %if.end ]
+  ret i64 %res
+}
+
+!1 = !{!"branch_weights", i32 1, i32 2000}
+!2 = !{!"branch_weights", i32 2000, i32 1}