diff --git a/lib/Target/ARM/ARMInstrInfo.td b/lib/Target/ARM/ARMInstrInfo.td
index b1efab1e2fd..af508ee131a 100644
--- a/lib/Target/ARM/ARMInstrInfo.td
+++ b/lib/Target/ARM/ARMInstrInfo.td
@@ -1539,8 +1539,10 @@ def : ARMV6Pat<(or (and GPR:$src1, 0xFFFF0000),
 
 defm CMP  : AI1_cmp_irs<0b1010, "cmp",
                         BinOpFrag<(ARMcmp node:$LHS, node:$RHS)>>;
-defm CMN  : AI1_cmp_irs<0b1011, "cmn",
-                        BinOpFrag<(ARMcmp node:$LHS,(ineg node:$RHS))>>;
+//FIXME: Disable CMN, as CCodes are backwards from compare expectations
+//       Compare-to-zero still works out, just not the relationals
+//defm CMN  : AI1_cmp_irs<0b1011, "cmn",
+//                        BinOpFrag<(ARMcmp node:$LHS,(ineg node:$RHS))>>;
 
 // Note that TST/TEQ don't set all the same flags that CMP does!
 defm TST  : AI1_cmp_irs<0b1000, "tst",
@@ -1553,11 +1555,11 @@ defm CMPz  : AI1_cmp_irs<0b1010, "cmp",
 defm CMNz  : AI1_cmp_irs<0b1011, "cmn",
                          BinOpFrag<(ARMcmpZ node:$LHS,(ineg node:$RHS))>>;
 
-def : ARMPat<(ARMcmp GPR:$src, so_imm_neg:$imm),
-             (CMNri  GPR:$src, so_imm_neg:$imm)>;
+//def : ARMPat<(ARMcmp GPR:$src, so_imm_neg:$imm),
+//             (CMNri  GPR:$src, so_imm_neg:$imm)>;
 
 def : ARMPat<(ARMcmpZ GPR:$src, so_imm_neg:$imm),
-             (CMNri  GPR:$src, so_imm_neg:$imm)>;
+             (CMNzri  GPR:$src, so_imm_neg:$imm)>;
 
 
 // Conditional moves
diff --git a/lib/Target/ARM/ARMInstrThumb.td b/lib/Target/ARM/ARMInstrThumb.td
index c304ff9caa7..746caffe22e 100644
--- a/lib/Target/ARM/ARMInstrThumb.td
+++ b/lib/Target/ARM/ARMInstrThumb.td
@@ -534,10 +534,12 @@ def tBIC : T1sIt<(outs tGPR:$dst), (ins tGPR:$lhs, tGPR:$rhs), IIC_iALUr,
 
 // CMN register
 let Defs = [CPSR] in {
-def tCMN : T1pI<(outs), (ins tGPR:$lhs, tGPR:$rhs), IIC_iCMPr,
-                "cmn", "\t$lhs, $rhs",
-                [(ARMcmp tGPR:$lhs, (ineg tGPR:$rhs))]>,
-           T1DataProcessing<0b1011>;
+//FIXME: Disable CMN, as CCodes are backwards from compare expectations
+//       Compare-to-zero still works out, just not the relationals
+//def tCMN : T1pI<(outs), (ins tGPR:$lhs, tGPR:$rhs), IIC_iCMPr,
+//                "cmn", "\t$lhs, $rhs",
+//                [(ARMcmp tGPR:$lhs, (ineg tGPR:$rhs))]>,
+//           T1DataProcessing<0b1011>;
 def tCMNz : T1pI<(outs), (ins tGPR:$lhs, tGPR:$rhs), IIC_iCMPr,
                  "cmn", "\t$lhs, $rhs",
                  [(ARMcmpZ tGPR:$lhs, (ineg tGPR:$rhs))]>,
diff --git a/lib/Target/ARM/ARMInstrThumb2.td b/lib/Target/ARM/ARMInstrThumb2.td
index 34a793cbbd2..c7591d21cd1 100644
--- a/lib/Target/ARM/ARMInstrThumb2.td
+++ b/lib/Target/ARM/ARMInstrThumb2.td
@@ -1609,16 +1609,18 @@ defm t2CMP  : T2I_cmp_irs<0b1101, "cmp",
 defm t2CMPz : T2I_cmp_irs<0b1101, "cmp",
                           BinOpFrag<(ARMcmpZ node:$LHS, node:$RHS)>>;
 
-defm t2CMN  : T2I_cmp_irs<0b1000, "cmn",
-                          BinOpFrag<(ARMcmp node:$LHS,(ineg node:$RHS))>>;
+//FIXME: Disable CMN, as CCodes are backwards from compare expectations
+//       Compare-to-zero still works out, just not the relationals
+//defm t2CMN  : T2I_cmp_irs<0b1000, "cmn",
+//                          BinOpFrag<(ARMcmp node:$LHS,(ineg node:$RHS))>>;
 defm t2CMNz : T2I_cmp_irs<0b1000, "cmn",
                           BinOpFrag<(ARMcmpZ node:$LHS,(ineg node:$RHS))>>;
 
-def : T2Pat<(ARMcmp  GPR:$src, t2_so_imm_neg:$imm),
-            (t2CMNri GPR:$src, t2_so_imm_neg:$imm)>;
+//def : T2Pat<(ARMcmp  GPR:$src, t2_so_imm_neg:$imm),
+//            (t2CMNri GPR:$src, t2_so_imm_neg:$imm)>;
 
 def : T2Pat<(ARMcmpZ  GPR:$src, t2_so_imm_neg:$imm),
-            (t2CMNri   GPR:$src, t2_so_imm_neg:$imm)>;
+            (t2CMNzri GPR:$src, t2_so_imm_neg:$imm)>;
 
 defm t2TST  : T2I_cmp_irs<0b0000, "tst",
                           BinOpFrag<(ARMcmpZ (and node:$LHS, node:$RHS), 0)>>;
diff --git a/lib/Target/ARM/README.txt b/lib/Target/ARM/README.txt
index 11c48add21b..a6f26a5dfe1 100644
--- a/lib/Target/ARM/README.txt
+++ b/lib/Target/ARM/README.txt
@@ -596,3 +596,12 @@ Make use of the "rbit" instruction.
 
 Take a look at test/CodeGen/Thumb2/machine-licm.ll. ARM should be taught how
 to licm and cse the unnecessary load from cp#1.
+
+//===---------------------------------------------------------------------===//
+
+The CMN instruction sets the flags like an ADD instruction, while CMP sets
+them like a subtract. Therefore to be able to use CMN for comparisons other
+than the Z bit, we'll need additional logic to reverse the conditionals
+associated with the comparison. Perhaps a pseudo-instruction for the comparison,
+with a post-codegen pass to clean up and handle the condition codes?
+See PR5694 for testcase.
diff --git a/lib/Target/ARM/Thumb2SizeReduction.cpp b/lib/Target/ARM/Thumb2SizeReduction.cpp
index 35359aa549a..95288bfc261 100644
--- a/lib/Target/ARM/Thumb2SizeReduction.cpp
+++ b/lib/Target/ARM/Thumb2SizeReduction.cpp
@@ -65,7 +65,8 @@ namespace {
     { ARM::t2ASRri, ARM::tASRri,  0,             5,   0,    1,   0,  0,0, 0 },
     { ARM::t2ASRrr, 0,            ARM::tASRrr,   0,   0,    0,   1,  0,0, 0 },
     { ARM::t2BICrr, 0,            ARM::tBIC,     0,   0,    0,   1,  0,0, 0 },
-    { ARM::t2CMNrr, ARM::tCMN,    0,             0,   0,    1,   0,  2,0, 0 },
+    //FIXME: Disable CMN, as CCodes are backwards from compare expectations
+    //{ ARM::t2CMNrr, ARM::tCMN,    0,             0,   0,    1,   0,  2,0, 0 },
     { ARM::t2CMPri, ARM::tCMPi8,  0,             8,   0,    1,   0,  2,0, 0 },
     { ARM::t2CMPrr, ARM::tCMPhir, 0,             0,   0,    0,   0,  2,0, 0 },
     { ARM::t2CMPzri,ARM::tCMPzi8, 0,             8,   0,    1,   0,  2,0, 0 },