diff --git a/llvm/lib/Target/PowerPC/PPCInstr64Bit.td b/llvm/lib/Target/PowerPC/PPCInstr64Bit.td
--- a/llvm/lib/Target/PowerPC/PPCInstr64Bit.td
+++ b/llvm/lib/Target/PowerPC/PPCInstr64Bit.td
@@ -573,14 +573,16 @@
                            "mtctr $rS", IIC_SprMTSPR>,
              PPC970_DGroup_First, PPC970_Unit_FXU;
 }
-let hasSideEffects = 1, Defs = [CTR8] in {
+// MTCTR[8|]loop must be inside a loop-preheader, duplicating
+// the loop-preheader block will break this assumption.
+let hasSideEffects = 1, isNotDuplicable = 1, Defs = [CTR8] in {
 let Pattern = [(int_set_loop_iterations i64:$rS)] in
 def MTCTR8loop : XFXForm_7_ext<31, 467, 9, (outs), (ins g8rc:$rS),
                                "mtctr $rS", IIC_SprMTSPR>,
                  PPC970_DGroup_First, PPC970_Unit_FXU;
 }
 
-let hasSideEffects = 1, hasNoSchedulingInfo = 1, Uses = [CTR8], Defs = [CTR8] in
+let hasSideEffects = 1, hasNoSchedulingInfo = 1, isNotDuplicable = 1, Uses = [CTR8], Defs = [CTR8] in
 def DecreaseCTR8loop : PPCEmitTimePseudo<(outs crbitrc:$rT), (ins i64imm:$stride),
                                         "#DecreaseCTR8loop", [(set i1:$rT, (int_loop_decrement (i64 imm:$stride)))]>;
 
diff --git a/llvm/lib/Target/PowerPC/PPCInstrInfo.td b/llvm/lib/Target/PowerPC/PPCInstrInfo.td
--- a/llvm/lib/Target/PowerPC/PPCInstrInfo.td
+++ b/llvm/lib/Target/PowerPC/PPCInstrInfo.td
@@ -2548,14 +2548,14 @@
                           "mtctr $rS", IIC_SprMTSPR>,
             PPC970_DGroup_First, PPC970_Unit_FXU;
 }
-let hasSideEffects = 1, isCodeGenOnly = 1, Defs = [CTR] in {
+let hasSideEffects = 1, isCodeGenOnly = 1, isNotDuplicable = 1, Defs = [CTR] in {
 let Pattern = [(int_set_loop_iterations i32:$rS)] in
 def MTCTRloop : XFXForm_7_ext<31, 467, 9, (outs), (ins gprc:$rS),
                               "mtctr $rS", IIC_SprMTSPR>,
                 PPC970_DGroup_First, PPC970_Unit_FXU;
 }
 
-let hasSideEffects = 1, hasNoSchedulingInfo = 1, Uses = [CTR], Defs = [CTR] in
+let hasSideEffects = 1, hasNoSchedulingInfo = 1, isNotDuplicable = 1, Uses = [CTR], Defs = [CTR] in
 def DecreaseCTRloop : PPCEmitTimePseudo<(outs crbitrc:$rT), (ins i32imm:$stride),
                                        "#DecreaseCTRloop", [(set i1:$rT, (int_loop_decrement (i32 imm:$stride)))]>;
 
diff --git a/llvm/test/CodeGen/PowerPC/ctrloop-do-not-duplicate-mi.mir b/llvm/test/CodeGen/PowerPC/ctrloop-do-not-duplicate-mi.mir
--- a/llvm/test/CodeGen/PowerPC/ctrloop-do-not-duplicate-mi.mir
+++ b/llvm/test/CodeGen/PowerPC/ctrloop-do-not-duplicate-mi.mir
@@ -1,7 +1,6 @@
-# RUN: not --crash llc -ppc-asm-full-reg-names -mtriple=powerpc64le-unknown-linux-gnu \
+# RUN: llc -ppc-asm-full-reg-names -mtriple=powerpc64le-unknown-linux-gnu \
 # RUN:   -run-pass=early-tailduplication,ppc-ctrloops %s -o - -verify-machineinstrs 2>&1 | FileCheck %s
 
-# CHECK: Invalid ctr loop
 --- |
   target datalayout = "e-m:e-i64:64-n32:64-S128-v256:256:256-v512:512:512"
   target triple = "powerpc64le-unknown-linux-gnu"
@@ -65,6 +64,7 @@
 ...
 ---
 name:            test
+# CHECK: test
 alignment:       16
 exposesReturnsTwice: false
 legalized:       false