[llvm] [ARM] Have custom lowering for ucmp and scmp (PR #149315)

via llvm-commits llvm-commits at lists.llvm.org
Mon Aug 4 12:18:22 PDT 2025


https://github.com/AZero13 updated https://github.com/llvm/llvm-project/pull/149315

>From dd3d30a9097f7452e276a8e730a66850438fbd0e Mon Sep 17 00:00:00 2001
From: Rose <gfunni234 at gmail.com>
Date: Thu, 17 Jul 2025 10:05:46 -0400
Subject: [PATCH 1/9] [ARM] Have custom lowering for ucmp and scmp

Limited to non-thumb at the moment, but we can do this for i32 in 3 steps, using subs to set the flags initially.
---
 llvm/lib/Target/ARM/ARMISelLowering.cpp | 145 ++++++++++++++++++++++++
 llvm/lib/Target/ARM/ARMISelLowering.h   |   2 +
 llvm/test/CodeGen/ARM/scmp.ll           |  48 ++++----
 llvm/test/CodeGen/ARM/ucmp.ll           |  36 ++----
 4 files changed, 183 insertions(+), 48 deletions(-)

diff --git a/llvm/lib/Target/ARM/ARMISelLowering.cpp b/llvm/lib/Target/ARM/ARMISelLowering.cpp
index 65d1c4e2d6515..9681eab17518b 100644
--- a/llvm/lib/Target/ARM/ARMISelLowering.cpp
+++ b/llvm/lib/Target/ARM/ARMISelLowering.cpp
@@ -802,6 +802,11 @@ ARMTargetLowering::ARMTargetLowering(const TargetMachine &TM_,
     setOperationAction(ISD::BSWAP, VT, Expand);
   }
 
+  if (!Subtarget->isThumb()) {
+    setOperationAction(ISD::SCMP, MVT::i32, Custom);
+    setOperationAction(ISD::UCMP, MVT::i32, Custom);
+  }
+
   setOperationAction(ISD::ConstantFP, MVT::f32, Custom);
   setOperationAction(ISD::ConstantFP, MVT::f64, Custom);
 
@@ -10614,6 +10619,142 @@ SDValue ARMTargetLowering::LowerFP_TO_BF16(SDValue Op,
   return DAG.getBitcast(MVT::i32, Res);
 }
 
+SDValue ARMTargetLowering::LowerSCMP(SDValue Op, SelectionDAG &DAG) const {
+  SDLoc dl(Op);
+  SDValue LHS = Op.getOperand(0);
+  SDValue RHS = Op.getOperand(1);
+
+  // For the ARM assembly pattern:
+  // subs r0, r0, r1   ; subtract RHS from LHS and set flags
+  // movgt r0, #1      ; if LHS > RHS, set result to 1
+  // mvnlt r0, #0      ; if LHS < RHS, set result to -1 (mvn #0 = -1)
+  //                   ; if LHS == RHS, result remains 0 from the subs
+
+  // Optimization: if RHS is a subtraction against 0, use ADDC instead of SUBC
+  // Check if RHS is (0 - something), and if so use ADDC with LHS + something
+  SDValue SubResult, Flags;
+  bool CanUseAdd = false;
+  SDValue AddOperand;
+
+  // Check if RHS is a subtraction against 0: (0 - X)
+  if (RHS.getOpcode() == ISD::SUB) {
+    SDValue SubLHS = RHS.getOperand(0);
+    SDValue SubRHS = RHS.getOperand(1);
+
+    // Check if it's 0 - X
+    if (isNullConstant(SubLHS)) {
+      // For SCMP: only if X is known to never be INT_MIN (to avoid overflow)
+      if (RHS->getFlags().hasNoSignedWrap() || !DAG.computeKnownBits(SubRHS)
+                                                    .getSignedMinValue()
+                                                    .isMinSignedValue()) {
+        CanUseAdd = true;
+        AddOperand = SubRHS; // Replace RHS with X, so we do LHS + X instead of
+                             // LHS - (0 - X)
+      }
+    }
+  }
+
+  if (CanUseAdd) {
+    // Use ADDC: LHS + AddOperand (where RHS was 0 - AddOperand)
+    SDValue AddWithFlags = DAG.getNode(
+        ARMISD::ADDC, dl, DAG.getVTList(MVT::i32, FlagsVT), LHS, AddOperand);
+    SubResult = AddWithFlags.getValue(0); // The addition result
+    Flags = AddWithFlags.getValue(1);     // The flags from ADDS
+  } else {
+    // Use ARMISD::SUBC to generate SUBS instruction (subtract with flags)
+    SDValue SubWithFlags = DAG.getNode(
+        ARMISD::SUBC, dl, DAG.getVTList(MVT::i32, FlagsVT), LHS, RHS);
+    SubResult = SubWithFlags.getValue(0); // The subtraction result
+    Flags = SubWithFlags.getValue(1);     // The flags from SUBS
+  }
+
+  // Constants for conditional moves
+  SDValue One = DAG.getConstant(1, dl, MVT::i32);
+  SDValue MinusOne = DAG.getConstant(0xFFFFFFFF, dl, MVT::i32);
+
+  // movgt: if greater than, set to 1
+  SDValue GTCond = DAG.getConstant(ARMCC::GT, dl, MVT::i32);
+  SDValue Result1 =
+      DAG.getNode(ARMISD::CMOV, dl, MVT::i32, SubResult, One, GTCond, Flags);
+
+  // mvnlt: if less than, set to -1 (equivalent to mvn #0)
+  SDValue LTCond = DAG.getConstant(ARMCC::LT, dl, MVT::i32);
+  SDValue Result2 =
+      DAG.getNode(ARMISD::CMOV, dl, MVT::i32, Result1, MinusOne, LTCond, Flags);
+
+  if (Op.getValueType() != MVT::i32)
+    Result2 = DAG.getSExtOrTrunc(Result2, dl, Op.getValueType());
+
+  return Result2;
+}
+
+SDValue ARMTargetLowering::LowerUCMP(SDValue Op, SelectionDAG &DAG) const {
+  SDLoc dl(Op);
+  SDValue LHS = Op.getOperand(0);
+  SDValue RHS = Op.getOperand(1);
+
+  // For the ARM assembly pattern (unsigned version):
+  // subs r0, r0, r1   ; subtract RHS from LHS and set flags
+  // movhi r0, #1      ; if LHS > RHS (unsigned), set result to 1
+  // mvnlo r0, #0      ; if LHS < RHS (unsigned), set result to -1
+  //                   ; if LHS == RHS, result remains 0 from the subs
+
+  // Optimization: if RHS is a subtraction against 0, use ADDC instead of SUBC
+  // Check if RHS is (0 - something), and if so use ADDC with LHS + something
+  SDValue SubResult, Flags;
+  bool CanUseAdd = false;
+  SDValue AddOperand;
+
+  // Check if RHS is a subtraction against 0: (0 - X)
+  if (RHS.getOpcode() == ISD::SUB) {
+    SDValue SubLHS = RHS.getOperand(0);
+    SDValue SubRHS = RHS.getOperand(1);
+
+    // Check if it's 0 - X
+    if (isNullConstant(SubLHS)) {
+      // For UCMP: only if X is known to never be zero
+      if (DAG.isKnownNeverZero(SubRHS)) {
+        CanUseAdd = true;
+        AddOperand = SubRHS; // Replace RHS with X, so we do LHS + X instead of
+                             // LHS - (0 - X)
+      }
+    }
+  }
+
+  if (CanUseAdd) {
+    // Use ADDC: LHS + AddOperand (where RHS was 0 - AddOperand)
+    SDValue AddWithFlags = DAG.getNode(
+        ARMISD::ADDC, dl, DAG.getVTList(MVT::i32, FlagsVT), LHS, AddOperand);
+    SubResult = AddWithFlags.getValue(0); // The addition result
+    Flags = AddWithFlags.getValue(1);     // The flags from ADDS
+  } else {
+    // Use ARMISD::SUBC to generate SUBS instruction (subtract with flags)
+    SDValue SubWithFlags = DAG.getNode(
+        ARMISD::SUBC, dl, DAG.getVTList(MVT::i32, FlagsVT), LHS, RHS);
+    SubResult = SubWithFlags.getValue(0); // The subtraction result
+    Flags = SubWithFlags.getValue(1);     // The flags from SUBS
+  }
+
+  // Constants for conditional moves
+  SDValue One = DAG.getConstant(1, dl, MVT::i32);
+  SDValue MinusOne = DAG.getConstant(0xFFFFFFFF, dl, MVT::i32);
+
+  // movhi: if higher (unsigned greater than), set to 1
+  SDValue HICond = DAG.getConstant(ARMCC::HI, dl, MVT::i32);
+  SDValue Result1 =
+      DAG.getNode(ARMISD::CMOV, dl, MVT::i32, SubResult, One, HICond, Flags);
+
+  // mvnlo: if lower (unsigned less than), set to -1
+  SDValue LOCond = DAG.getConstant(ARMCC::LO, dl, MVT::i32);
+  SDValue Result2 =
+      DAG.getNode(ARMISD::CMOV, dl, MVT::i32, Result1, MinusOne, LOCond, Flags);
+
+  if (Op.getValueType() != MVT::i32)
+    Result2 = DAG.getSExtOrTrunc(Result2, dl, Op.getValueType());
+
+  return Result2;
+}
+
 SDValue ARMTargetLowering::LowerOperation(SDValue Op, SelectionDAG &DAG) const {
   LLVM_DEBUG(dbgs() << "Lowering node: "; Op.dump());
   switch (Op.getOpcode()) {
@@ -10742,6 +10883,10 @@ SDValue ARMTargetLowering::LowerOperation(SDValue Op, SelectionDAG &DAG) const {
   case ISD::FP_TO_BF16:
     return LowerFP_TO_BF16(Op, DAG);
   case ARMISD::WIN__DBZCHK: return SDValue();
+  case ISD::SCMP:
+    return LowerSCMP(Op, DAG);
+  case ISD::UCMP:
+    return LowerUCMP(Op, DAG);
   }
 }
 
diff --git a/llvm/lib/Target/ARM/ARMISelLowering.h b/llvm/lib/Target/ARM/ARMISelLowering.h
index 5f4aef55b22c9..1cb7edd041b32 100644
--- a/llvm/lib/Target/ARM/ARMISelLowering.h
+++ b/llvm/lib/Target/ARM/ARMISelLowering.h
@@ -903,6 +903,8 @@ class VectorType;
     void LowerLOAD(SDNode *N, SmallVectorImpl<SDValue> &Results,
                    SelectionDAG &DAG) const;
     SDValue LowerFP_TO_BF16(SDValue Op, SelectionDAG &DAG) const;
+    SDValue LowerSCMP(SDValue Op, SelectionDAG &DAG) const;
+    SDValue LowerUCMP(SDValue Op, SelectionDAG &DAG) const;
 
     Register getRegisterByName(const char* RegName, LLT VT,
                                const MachineFunction &MF) const override;
diff --git a/llvm/test/CodeGen/ARM/scmp.ll b/llvm/test/CodeGen/ARM/scmp.ll
index 6e493c993751c..9189aee6aaf43 100644
--- a/llvm/test/CodeGen/ARM/scmp.ll
+++ b/llvm/test/CodeGen/ARM/scmp.ll
@@ -4,12 +4,9 @@
 define i8 @scmp_8_8(i8 signext %x, i8 signext %y) nounwind {
 ; CHECK-LABEL: scmp_8_8:
 ; CHECK:       @ %bb.0:
-; CHECK-NEXT:    cmp r0, r1
-; CHECK-NEXT:    mov r0, #0
-; CHECK-NEXT:    mov r2, #0
-; CHECK-NEXT:    movwlt r0, #1
-; CHECK-NEXT:    movwgt r2, #1
-; CHECK-NEXT:    sub r0, r2, r0
+; CHECK-NEXT:    subs r0, r0, r1
+; CHECK-NEXT:    movwgt r0, #1
+; CHECK-NEXT:    mvnlt r0, #0
 ; CHECK-NEXT:    bx lr
   %1 = call i8 @llvm.scmp(i8 %x, i8 %y)
   ret i8 %1
@@ -18,12 +15,9 @@ define i8 @scmp_8_8(i8 signext %x, i8 signext %y) nounwind {
 define i8 @scmp_8_16(i16 signext %x, i16 signext %y) nounwind {
 ; CHECK-LABEL: scmp_8_16:
 ; CHECK:       @ %bb.0:
-; CHECK-NEXT:    cmp r0, r1
-; CHECK-NEXT:    mov r0, #0
-; CHECK-NEXT:    mov r2, #0
-; CHECK-NEXT:    movwlt r0, #1
-; CHECK-NEXT:    movwgt r2, #1
-; CHECK-NEXT:    sub r0, r2, r0
+; CHECK-NEXT:    subs r0, r0, r1
+; CHECK-NEXT:    movwgt r0, #1
+; CHECK-NEXT:    mvnlt r0, #0
 ; CHECK-NEXT:    bx lr
   %1 = call i8 @llvm.scmp(i16 %x, i16 %y)
   ret i8 %1
@@ -32,12 +26,9 @@ define i8 @scmp_8_16(i16 signext %x, i16 signext %y) nounwind {
 define i8 @scmp_8_32(i32 %x, i32 %y) nounwind {
 ; CHECK-LABEL: scmp_8_32:
 ; CHECK:       @ %bb.0:
-; CHECK-NEXT:    cmp r0, r1
-; CHECK-NEXT:    mov r0, #0
-; CHECK-NEXT:    mov r2, #0
-; CHECK-NEXT:    movwlt r0, #1
-; CHECK-NEXT:    movwgt r2, #1
-; CHECK-NEXT:    sub r0, r2, r0
+; CHECK-NEXT:    subs r0, r0, r1
+; CHECK-NEXT:    movwgt r0, #1
+; CHECK-NEXT:    mvnlt r0, #0
 ; CHECK-NEXT:    bx lr
   %1 = call i8 @llvm.scmp(i32 %x, i32 %y)
   ret i8 %1
@@ -92,17 +83,26 @@ define i8 @scmp_8_128(i128 %x, i128 %y) nounwind {
 define i32 @scmp_32_32(i32 %x, i32 %y) nounwind {
 ; CHECK-LABEL: scmp_32_32:
 ; CHECK:       @ %bb.0:
-; CHECK-NEXT:    cmp r0, r1
-; CHECK-NEXT:    mov r0, #0
-; CHECK-NEXT:    mov r2, #0
-; CHECK-NEXT:    movwlt r0, #1
-; CHECK-NEXT:    movwgt r2, #1
-; CHECK-NEXT:    sub r0, r2, r0
+; CHECK-NEXT:    subs r0, r0, r1
+; CHECK-NEXT:    movwgt r0, #1
+; CHECK-NEXT:    mvnlt r0, #0
 ; CHECK-NEXT:    bx lr
   %1 = call i32 @llvm.scmp(i32 %x, i32 %y)
   ret i32 %1
 }
 
+define i32 @scmp_neg(i32 %x, i32 %y) nounwind {
+; CHECK-LABEL: scmp_neg:
+; CHECK:       @ %bb.0:
+; CHECK-NEXT:    adds r0, r0, r1
+; CHECK-NEXT:    movwgt r0, #1
+; CHECK-NEXT:    mvnlt r0, #0
+; CHECK-NEXT:    bx lr
+  %yy = sub nsw i32 0, %y
+  %1 = call i32 @llvm.scmp(i32 %x, i32 %yy)
+  ret i32 %1
+}
+
 define i32 @scmp_32_64(i64 %x, i64 %y) nounwind {
 ; CHECK-LABEL: scmp_32_64:
 ; CHECK:       @ %bb.0:
diff --git a/llvm/test/CodeGen/ARM/ucmp.ll b/llvm/test/CodeGen/ARM/ucmp.ll
index ad4af534ee8fe..bb0201454d1ea 100644
--- a/llvm/test/CodeGen/ARM/ucmp.ll
+++ b/llvm/test/CodeGen/ARM/ucmp.ll
@@ -4,12 +4,9 @@
 define i8 @ucmp_8_8(i8 zeroext %x, i8 zeroext %y) nounwind {
 ; CHECK-LABEL: ucmp_8_8:
 ; CHECK:       @ %bb.0:
-; CHECK-NEXT:    cmp r0, r1
-; CHECK-NEXT:    mov r0, #0
-; CHECK-NEXT:    mov r2, #0
-; CHECK-NEXT:    movwlo r0, #1
-; CHECK-NEXT:    movwhi r2, #1
-; CHECK-NEXT:    sub r0, r2, r0
+; CHECK-NEXT:    subs r0, r0, r1
+; CHECK-NEXT:    movwhi r0, #1
+; CHECK-NEXT:    mvnlo r0, #0
 ; CHECK-NEXT:    bx lr
   %1 = call i8 @llvm.ucmp(i8 %x, i8 %y)
   ret i8 %1
@@ -18,12 +15,9 @@ define i8 @ucmp_8_8(i8 zeroext %x, i8 zeroext %y) nounwind {
 define i8 @ucmp_8_16(i16 zeroext %x, i16 zeroext %y) nounwind {
 ; CHECK-LABEL: ucmp_8_16:
 ; CHECK:       @ %bb.0:
-; CHECK-NEXT:    cmp r0, r1
-; CHECK-NEXT:    mov r0, #0
-; CHECK-NEXT:    mov r2, #0
-; CHECK-NEXT:    movwlo r0, #1
-; CHECK-NEXT:    movwhi r2, #1
-; CHECK-NEXT:    sub r0, r2, r0
+; CHECK-NEXT:    subs r0, r0, r1
+; CHECK-NEXT:    movwhi r0, #1
+; CHECK-NEXT:    mvnlo r0, #0
 ; CHECK-NEXT:    bx lr
   %1 = call i8 @llvm.ucmp(i16 %x, i16 %y)
   ret i8 %1
@@ -32,12 +26,9 @@ define i8 @ucmp_8_16(i16 zeroext %x, i16 zeroext %y) nounwind {
 define i8 @ucmp_8_32(i32 %x, i32 %y) nounwind {
 ; CHECK-LABEL: ucmp_8_32:
 ; CHECK:       @ %bb.0:
-; CHECK-NEXT:    cmp r0, r1
-; CHECK-NEXT:    mov r0, #0
-; CHECK-NEXT:    mov r2, #0
-; CHECK-NEXT:    movwlo r0, #1
-; CHECK-NEXT:    movwhi r2, #1
-; CHECK-NEXT:    sub r0, r2, r0
+; CHECK-NEXT:    subs r0, r0, r1
+; CHECK-NEXT:    movwhi r0, #1
+; CHECK-NEXT:    mvnlo r0, #0
 ; CHECK-NEXT:    bx lr
   %1 = call i8 @llvm.ucmp(i32 %x, i32 %y)
   ret i8 %1
@@ -92,12 +83,9 @@ define i8 @ucmp_8_128(i128 %x, i128 %y) nounwind {
 define i32 @ucmp_32_32(i32 %x, i32 %y) nounwind {
 ; CHECK-LABEL: ucmp_32_32:
 ; CHECK:       @ %bb.0:
-; CHECK-NEXT:    cmp r0, r1
-; CHECK-NEXT:    mov r0, #0
-; CHECK-NEXT:    mov r2, #0
-; CHECK-NEXT:    movwlo r0, #1
-; CHECK-NEXT:    movwhi r2, #1
-; CHECK-NEXT:    sub r0, r2, r0
+; CHECK-NEXT:    subs r0, r0, r1
+; CHECK-NEXT:    movwhi r0, #1
+; CHECK-NEXT:    mvnlo r0, #0
 ; CHECK-NEXT:    bx lr
   %1 = call i32 @llvm.ucmp(i32 %x, i32 %y)
   ret i32 %1

>From 6719da6a2c9448cee2133f713e3836cfa4363508 Mon Sep 17 00:00:00 2001
From: Rose <gfunni234 at gmail.com>
Date: Thu, 17 Jul 2025 17:54:42 -0400
Subject: [PATCH 2/9] Thumb1 support for ucmp

There is no real good way to do scmp sadly
---
 llvm/lib/Target/ARM/ARMISelLowering.cpp |  44 ++-
 llvm/test/CodeGen/Thumb/scmp.ll         |  44 ++-
 llvm/test/CodeGen/Thumb/ucmp.ll         | 359 ++++++++++++++++--------
 3 files changed, 306 insertions(+), 141 deletions(-)

diff --git a/llvm/lib/Target/ARM/ARMISelLowering.cpp b/llvm/lib/Target/ARM/ARMISelLowering.cpp
index 9681eab17518b..55fd9c637c33f 100644
--- a/llvm/lib/Target/ARM/ARMISelLowering.cpp
+++ b/llvm/lib/Target/ARM/ARMISelLowering.cpp
@@ -802,10 +802,9 @@ ARMTargetLowering::ARMTargetLowering(const TargetMachine &TM_,
     setOperationAction(ISD::BSWAP, VT, Expand);
   }
 
-  if (!Subtarget->isThumb()) {
+  if (!Subtarget->isThumb1Only())
     setOperationAction(ISD::SCMP, MVT::i32, Custom);
-    setOperationAction(ISD::UCMP, MVT::i32, Custom);
-  }
+  setOperationAction(ISD::UCMP, MVT::i32, Custom);
 
   setOperationAction(ISD::ConstantFP, MVT::f32, Custom);
   setOperationAction(ISD::ConstantFP, MVT::f64, Custom);
@@ -10693,6 +10692,45 @@ SDValue ARMTargetLowering::LowerUCMP(SDValue Op, SelectionDAG &DAG) const {
   SDValue LHS = Op.getOperand(0);
   SDValue RHS = Op.getOperand(1);
 
+  if (Subtarget->isThumb1Only()) {
+    // For Thumb unsigned comparison, use this sequence:
+    // subs r2, r0, r1   ; r2 = LHS - RHS, sets flags
+    // sbc r2, r2        ; r2 = r2 - r2 - !carry
+    // cmp r1, r0        ; compare RHS with LHS
+    // sbc r1, r1        ; r1 = r1 - r1 - !carry
+    // subs r0, r2, r1   ; r0 = r2 - r1 (final result)
+
+    // First subtraction: LHS - RHS
+    SDValue Sub1WithFlags = DAG.getNode(
+        ARMISD::SUBC, dl, DAG.getVTList(MVT::i32, FlagsVT), LHS, RHS);
+    SDValue Sub1Result = Sub1WithFlags.getValue(0);
+    SDValue Flags1 = Sub1WithFlags.getValue(1);
+
+    // SUBE: Sub1Result - Sub1Result - !carry
+    // This gives 0 if LHS >= RHS (unsigned), -1 if LHS < RHS (unsigned)
+    SDValue Sbc1 =
+        DAG.getNode(ARMISD::SUBE, dl, DAG.getVTList(MVT::i32, FlagsVT),
+                    Sub1Result, Sub1Result, Flags1);
+    SDValue Sbc1Result = Sbc1.getValue(0);
+
+    // Second comparison: RHS vs LHS (reverse comparison)
+    SDValue CmpFlags = DAG.getNode(ARMISD::CMP, dl, FlagsVT, RHS, LHS);
+
+    // SUBE: RHS - RHS - !carry
+    // This gives 0 if RHS <= LHS (unsigned), -1 if RHS > LHS (unsigned)
+    SDValue Sbc2 = DAG.getNode(
+        ARMISD::SUBE, dl, DAG.getVTList(MVT::i32, FlagsVT), RHS, RHS, CmpFlags);
+    SDValue Sbc2Result = Sbc2.getValue(0);
+
+    // Final subtraction: Sbc1Result - Sbc2Result (no flags needed)
+    SDValue Result =
+        DAG.getNode(ISD::SUB, dl, MVT::i32, Sbc1Result, Sbc2Result);
+    if (Op.getValueType() != MVT::i32)
+      Result = DAG.getSExtOrTrunc(Result, dl, Op.getValueType());
+
+    return Result;
+  }
+
   // For the ARM assembly pattern (unsigned version):
   // subs r0, r0, r1   ; subtract RHS from LHS and set flags
   // movhi r0, #1      ; if LHS > RHS (unsigned), set result to 1
diff --git a/llvm/test/CodeGen/Thumb/scmp.ll b/llvm/test/CodeGen/Thumb/scmp.ll
index 661dbe97cdb3c..be41f8f923f1e 100644
--- a/llvm/test/CodeGen/Thumb/scmp.ll
+++ b/llvm/test/CodeGen/Thumb/scmp.ll
@@ -4,14 +4,11 @@
 define i8 @scmp_8_8(i8 signext %x, i8 signext %y) nounwind {
 ; CHECK-LABEL: scmp_8_8:
 ; CHECK:       @ %bb.0:
-; CHECK-NEXT:    cmp r0, r1
-; CHECK-NEXT:    mov.w r0, #0
-; CHECK-NEXT:    mov.w r2, #0
-; CHECK-NEXT:    it lt
-; CHECK-NEXT:    movlt r0, #1
+; CHECK-NEXT:    subs r0, r0, r1
 ; CHECK-NEXT:    it gt
-; CHECK-NEXT:    movgt r2, #1
-; CHECK-NEXT:    subs r0, r2, r0
+; CHECK-NEXT:    movgt r0, #1
+; CHECK-NEXT:    it lt
+; CHECK-NEXT:    movlt.w r0, #-1
 ; CHECK-NEXT:    bx lr
   %1 = call i8 @llvm.scmp(i8 %x, i8 %y)
   ret i8 %1
@@ -20,14 +17,11 @@ define i8 @scmp_8_8(i8 signext %x, i8 signext %y) nounwind {
 define i8 @scmp_8_16(i16 signext %x, i16 signext %y) nounwind {
 ; CHECK-LABEL: scmp_8_16:
 ; CHECK:       @ %bb.0:
-; CHECK-NEXT:    cmp r0, r1
-; CHECK-NEXT:    mov.w r0, #0
-; CHECK-NEXT:    mov.w r2, #0
-; CHECK-NEXT:    it lt
-; CHECK-NEXT:    movlt r0, #1
+; CHECK-NEXT:    subs r0, r0, r1
 ; CHECK-NEXT:    it gt
-; CHECK-NEXT:    movgt r2, #1
-; CHECK-NEXT:    subs r0, r2, r0
+; CHECK-NEXT:    movgt r0, #1
+; CHECK-NEXT:    it lt
+; CHECK-NEXT:    movlt.w r0, #-1
 ; CHECK-NEXT:    bx lr
   %1 = call i8 @llvm.scmp(i16 %x, i16 %y)
   ret i8 %1
@@ -36,14 +30,11 @@ define i8 @scmp_8_16(i16 signext %x, i16 signext %y) nounwind {
 define i8 @scmp_8_32(i32 %x, i32 %y) nounwind {
 ; CHECK-LABEL: scmp_8_32:
 ; CHECK:       @ %bb.0:
-; CHECK-NEXT:    cmp r0, r1
-; CHECK-NEXT:    mov.w r0, #0
-; CHECK-NEXT:    mov.w r2, #0
-; CHECK-NEXT:    it lt
-; CHECK-NEXT:    movlt r0, #1
+; CHECK-NEXT:    subs r0, r0, r1
 ; CHECK-NEXT:    it gt
-; CHECK-NEXT:    movgt r2, #1
-; CHECK-NEXT:    subs r0, r2, r0
+; CHECK-NEXT:    movgt r0, #1
+; CHECK-NEXT:    it lt
+; CHECK-NEXT:    movlt.w r0, #-1
 ; CHECK-NEXT:    bx lr
   %1 = call i8 @llvm.scmp(i32 %x, i32 %y)
   ret i8 %1
@@ -98,14 +89,11 @@ define i8 @scmp_8_128(i128 %x, i128 %y) nounwind {
 define i32 @scmp_32_32(i32 %x, i32 %y) nounwind {
 ; CHECK-LABEL: scmp_32_32:
 ; CHECK:       @ %bb.0:
-; CHECK-NEXT:    cmp r0, r1
-; CHECK-NEXT:    mov.w r0, #0
-; CHECK-NEXT:    mov.w r2, #0
-; CHECK-NEXT:    it lt
-; CHECK-NEXT:    movlt r0, #1
+; CHECK-NEXT:    subs r0, r0, r1
 ; CHECK-NEXT:    it gt
-; CHECK-NEXT:    movgt r2, #1
-; CHECK-NEXT:    subs r0, r2, r0
+; CHECK-NEXT:    movgt r0, #1
+; CHECK-NEXT:    it lt
+; CHECK-NEXT:    movlt.w r0, #-1
 ; CHECK-NEXT:    bx lr
   %1 = call i32 @llvm.scmp(i32 %x, i32 %y)
   ret i32 %1
diff --git a/llvm/test/CodeGen/Thumb/ucmp.ll b/llvm/test/CodeGen/Thumb/ucmp.ll
index 7e6d0a323b11c..25cf98cb343df 100644
--- a/llvm/test/CodeGen/Thumb/ucmp.ll
+++ b/llvm/test/CodeGen/Thumb/ucmp.ll
@@ -1,151 +1,290 @@
 ; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 5
-; RUN: llc -mtriple=thumbv7-apple-darwin %s -o - | FileCheck %s
+; RUN: llc -mtriple=thumbv6m-eabi %s -o - | FileCheck %s -check-prefix=THUMB1
+; RUN: llc -mtriple=thumbv7-apple-darwin %s -o - | FileCheck %s -check-prefix=THUMB2
 
 define i8 @ucmp_8_8(i8 zeroext %x, i8 zeroext %y) nounwind {
-; CHECK-LABEL: ucmp_8_8:
-; CHECK:       @ %bb.0:
-; CHECK-NEXT:    cmp r0, r1
-; CHECK-NEXT:    mov.w r0, #0
-; CHECK-NEXT:    mov.w r2, #0
-; CHECK-NEXT:    it lo
-; CHECK-NEXT:    movlo r0, #1
-; CHECK-NEXT:    it hi
-; CHECK-NEXT:    movhi r2, #1
-; CHECK-NEXT:    subs r0, r2, r0
-; CHECK-NEXT:    bx lr
+; THUMB1-LABEL: ucmp_8_8:
+; THUMB1:       @ %bb.0:
+; THUMB1-NEXT:    subs r2, r0, r1
+; THUMB1-NEXT:    sbcs r2, r2
+; THUMB1-NEXT:    cmp r1, r0
+; THUMB1-NEXT:    sbcs r1, r1
+; THUMB1-NEXT:    subs r0, r2, r1
+; THUMB1-NEXT:    bx lr
+;
+; THUMB2-LABEL: ucmp_8_8:
+; THUMB2:       @ %bb.0:
+; THUMB2-NEXT:    subs r0, r0, r1
+; THUMB2-NEXT:    it hi
+; THUMB2-NEXT:    movhi r0, #1
+; THUMB2-NEXT:    it lo
+; THUMB2-NEXT:    movlo.w r0, #-1
+; THUMB2-NEXT:    bx lr
   %1 = call i8 @llvm.ucmp(i8 %x, i8 %y)
   ret i8 %1
 }
 
 define i8 @ucmp_8_16(i16 zeroext %x, i16 zeroext %y) nounwind {
-; CHECK-LABEL: ucmp_8_16:
-; CHECK:       @ %bb.0:
-; CHECK-NEXT:    cmp r0, r1
-; CHECK-NEXT:    mov.w r0, #0
-; CHECK-NEXT:    mov.w r2, #0
-; CHECK-NEXT:    it lo
-; CHECK-NEXT:    movlo r0, #1
-; CHECK-NEXT:    it hi
-; CHECK-NEXT:    movhi r2, #1
-; CHECK-NEXT:    subs r0, r2, r0
-; CHECK-NEXT:    bx lr
+; THUMB1-LABEL: ucmp_8_16:
+; THUMB1:       @ %bb.0:
+; THUMB1-NEXT:    subs r2, r0, r1
+; THUMB1-NEXT:    sbcs r2, r2
+; THUMB1-NEXT:    cmp r1, r0
+; THUMB1-NEXT:    sbcs r1, r1
+; THUMB1-NEXT:    subs r0, r2, r1
+; THUMB1-NEXT:    bx lr
+;
+; THUMB2-LABEL: ucmp_8_16:
+; THUMB2:       @ %bb.0:
+; THUMB2-NEXT:    subs r0, r0, r1
+; THUMB2-NEXT:    it hi
+; THUMB2-NEXT:    movhi r0, #1
+; THUMB2-NEXT:    it lo
+; THUMB2-NEXT:    movlo.w r0, #-1
+; THUMB2-NEXT:    bx lr
   %1 = call i8 @llvm.ucmp(i16 %x, i16 %y)
   ret i8 %1
 }
 
 define i8 @ucmp_8_32(i32 %x, i32 %y) nounwind {
-; CHECK-LABEL: ucmp_8_32:
-; CHECK:       @ %bb.0:
-; CHECK-NEXT:    cmp r0, r1
-; CHECK-NEXT:    mov.w r0, #0
-; CHECK-NEXT:    mov.w r2, #0
-; CHECK-NEXT:    it lo
-; CHECK-NEXT:    movlo r0, #1
-; CHECK-NEXT:    it hi
-; CHECK-NEXT:    movhi r2, #1
-; CHECK-NEXT:    subs r0, r2, r0
-; CHECK-NEXT:    bx lr
+; THUMB1-LABEL: ucmp_8_32:
+; THUMB1:       @ %bb.0:
+; THUMB1-NEXT:    subs r2, r0, r1
+; THUMB1-NEXT:    sbcs r2, r2
+; THUMB1-NEXT:    cmp r1, r0
+; THUMB1-NEXT:    sbcs r1, r1
+; THUMB1-NEXT:    subs r0, r2, r1
+; THUMB1-NEXT:    bx lr
+;
+; THUMB2-LABEL: ucmp_8_32:
+; THUMB2:       @ %bb.0:
+; THUMB2-NEXT:    subs r0, r0, r1
+; THUMB2-NEXT:    it hi
+; THUMB2-NEXT:    movhi r0, #1
+; THUMB2-NEXT:    it lo
+; THUMB2-NEXT:    movlo.w r0, #-1
+; THUMB2-NEXT:    bx lr
   %1 = call i8 @llvm.ucmp(i32 %x, i32 %y)
   ret i8 %1
 }
 
 define i8 @ucmp_8_64(i64 %x, i64 %y) nounwind {
-; CHECK-LABEL: ucmp_8_64:
-; CHECK:       @ %bb.0:
-; CHECK-NEXT:    subs.w r12, r0, r2
-; CHECK-NEXT:    mov.w r9, #0
-; CHECK-NEXT:    sbcs.w r12, r1, r3
-; CHECK-NEXT:    mov.w r12, #0
-; CHECK-NEXT:    it lo
-; CHECK-NEXT:    movlo.w r12, #1
-; CHECK-NEXT:    subs r0, r2, r0
-; CHECK-NEXT:    sbcs.w r0, r3, r1
-; CHECK-NEXT:    it lo
-; CHECK-NEXT:    movlo.w r9, #1
-; CHECK-NEXT:    sub.w r0, r9, r12
-; CHECK-NEXT:    bx lr
+; THUMB1-LABEL: ucmp_8_64:
+; THUMB1:       @ %bb.0:
+; THUMB1-NEXT:    .save {r4, r5, r6, lr}
+; THUMB1-NEXT:    push {r4, r5, r6, lr}
+; THUMB1-NEXT:    movs r4, #1
+; THUMB1-NEXT:    movs r5, #0
+; THUMB1-NEXT:    subs r6, r0, r2
+; THUMB1-NEXT:    mov r6, r1
+; THUMB1-NEXT:    sbcs r6, r3
+; THUMB1-NEXT:    mov r6, r4
+; THUMB1-NEXT:    blo .LBB3_2
+; THUMB1-NEXT:  @ %bb.1:
+; THUMB1-NEXT:    mov r6, r5
+; THUMB1-NEXT:  .LBB3_2:
+; THUMB1-NEXT:    subs r0, r2, r0
+; THUMB1-NEXT:    sbcs r3, r1
+; THUMB1-NEXT:    blo .LBB3_4
+; THUMB1-NEXT:  @ %bb.3:
+; THUMB1-NEXT:    mov r4, r5
+; THUMB1-NEXT:  .LBB3_4:
+; THUMB1-NEXT:    subs r0, r4, r6
+; THUMB1-NEXT:    pop {r4, r5, r6, pc}
+;
+; THUMB2-LABEL: ucmp_8_64:
+; THUMB2:       @ %bb.0:
+; THUMB2-NEXT:    subs.w r12, r0, r2
+; THUMB2-NEXT:    mov.w r9, #0
+; THUMB2-NEXT:    sbcs.w r12, r1, r3
+; THUMB2-NEXT:    mov.w r12, #0
+; THUMB2-NEXT:    it lo
+; THUMB2-NEXT:    movlo.w r12, #1
+; THUMB2-NEXT:    subs r0, r2, r0
+; THUMB2-NEXT:    sbcs.w r0, r3, r1
+; THUMB2-NEXT:    it lo
+; THUMB2-NEXT:    movlo.w r9, #1
+; THUMB2-NEXT:    sub.w r0, r9, r12
+; THUMB2-NEXT:    bx lr
   %1 = call i8 @llvm.ucmp(i64 %x, i64 %y)
   ret i8 %1
 }
 
 define i8 @ucmp_8_128(i128 %x, i128 %y) nounwind {
-; CHECK-LABEL: ucmp_8_128:
-; CHECK:       @ %bb.0:
-; CHECK-NEXT:    push {r4, r5, r6, lr}
-; CHECK-NEXT:    add.w lr, sp, #16
-; CHECK-NEXT:    ldr r4, [sp, #28]
-; CHECK-NEXT:    movs r5, #0
-; CHECK-NEXT:    ldm.w lr, {r9, r12, lr}
-; CHECK-NEXT:    subs.w r6, r0, r9
-; CHECK-NEXT:    sbcs.w r6, r1, r12
-; CHECK-NEXT:    sbcs.w r6, r2, lr
-; CHECK-NEXT:    sbcs.w r6, r3, r4
-; CHECK-NEXT:    mov.w r6, #0
-; CHECK-NEXT:    it lo
-; CHECK-NEXT:    movlo r6, #1
-; CHECK-NEXT:    subs.w r0, r9, r0
-; CHECK-NEXT:    sbcs.w r0, r12, r1
-; CHECK-NEXT:    sbcs.w r0, lr, r2
-; CHECK-NEXT:    sbcs.w r0, r4, r3
-; CHECK-NEXT:    it lo
-; CHECK-NEXT:    movlo r5, #1
-; CHECK-NEXT:    subs r0, r5, r6
-; CHECK-NEXT:    pop {r4, r5, r6, pc}
+; THUMB1-LABEL: ucmp_8_128:
+; THUMB1:       @ %bb.0:
+; THUMB1-NEXT:    .save {r4, r5, r6, r7, lr}
+; THUMB1-NEXT:    push {r4, r5, r6, r7, lr}
+; THUMB1-NEXT:    .pad #20
+; THUMB1-NEXT:    sub sp, #20
+; THUMB1-NEXT:    str r3, [sp, #16] @ 4-byte Spill
+; THUMB1-NEXT:    movs r3, #1
+; THUMB1-NEXT:    str r3, [sp] @ 4-byte Spill
+; THUMB1-NEXT:    movs r3, #0
+; THUMB1-NEXT:    str r3, [sp, #12] @ 4-byte Spill
+; THUMB1-NEXT:    ldr r6, [sp, #52]
+; THUMB1-NEXT:    add r7, sp, #40
+; THUMB1-NEXT:    ldm r7, {r3, r5, r7}
+; THUMB1-NEXT:    subs r4, r0, r3
+; THUMB1-NEXT:    str r1, [sp, #4] @ 4-byte Spill
+; THUMB1-NEXT:    mov r4, r1
+; THUMB1-NEXT:    ldr r1, [sp] @ 4-byte Reload
+; THUMB1-NEXT:    sbcs r4, r5
+; THUMB1-NEXT:    str r2, [sp, #8] @ 4-byte Spill
+; THUMB1-NEXT:    mov r4, r2
+; THUMB1-NEXT:    sbcs r4, r7
+; THUMB1-NEXT:    ldr r4, [sp, #16] @ 4-byte Reload
+; THUMB1-NEXT:    sbcs r4, r6
+; THUMB1-NEXT:    mov r2, r1
+; THUMB1-NEXT:    blo .LBB4_2
+; THUMB1-NEXT:  @ %bb.1:
+; THUMB1-NEXT:    ldr r2, [sp, #12] @ 4-byte Reload
+; THUMB1-NEXT:  .LBB4_2:
+; THUMB1-NEXT:    subs r0, r3, r0
+; THUMB1-NEXT:    ldr r0, [sp, #4] @ 4-byte Reload
+; THUMB1-NEXT:    sbcs r5, r0
+; THUMB1-NEXT:    ldr r0, [sp, #8] @ 4-byte Reload
+; THUMB1-NEXT:    sbcs r7, r0
+; THUMB1-NEXT:    ldr r0, [sp, #16] @ 4-byte Reload
+; THUMB1-NEXT:    sbcs r6, r0
+; THUMB1-NEXT:    blo .LBB4_4
+; THUMB1-NEXT:  @ %bb.3:
+; THUMB1-NEXT:    ldr r1, [sp, #12] @ 4-byte Reload
+; THUMB1-NEXT:  .LBB4_4:
+; THUMB1-NEXT:    subs r0, r1, r2
+; THUMB1-NEXT:    add sp, #20
+; THUMB1-NEXT:    pop {r4, r5, r6, r7, pc}
+;
+; THUMB2-LABEL: ucmp_8_128:
+; THUMB2:       @ %bb.0:
+; THUMB2-NEXT:    push {r4, r5, r6, lr}
+; THUMB2-NEXT:    add.w lr, sp, #16
+; THUMB2-NEXT:    ldr r4, [sp, #28]
+; THUMB2-NEXT:    movs r5, #0
+; THUMB2-NEXT:    ldm.w lr, {r9, r12, lr}
+; THUMB2-NEXT:    subs.w r6, r0, r9
+; THUMB2-NEXT:    sbcs.w r6, r1, r12
+; THUMB2-NEXT:    sbcs.w r6, r2, lr
+; THUMB2-NEXT:    sbcs.w r6, r3, r4
+; THUMB2-NEXT:    mov.w r6, #0
+; THUMB2-NEXT:    it lo
+; THUMB2-NEXT:    movlo r6, #1
+; THUMB2-NEXT:    subs.w r0, r9, r0
+; THUMB2-NEXT:    sbcs.w r0, r12, r1
+; THUMB2-NEXT:    sbcs.w r0, lr, r2
+; THUMB2-NEXT:    sbcs.w r0, r4, r3
+; THUMB2-NEXT:    it lo
+; THUMB2-NEXT:    movlo r5, #1
+; THUMB2-NEXT:    subs r0, r5, r6
+; THUMB2-NEXT:    pop {r4, r5, r6, pc}
   %1 = call i8 @llvm.ucmp(i128 %x, i128 %y)
   ret i8 %1
 }
 
 define i32 @ucmp_32_32(i32 %x, i32 %y) nounwind {
-; CHECK-LABEL: ucmp_32_32:
-; CHECK:       @ %bb.0:
-; CHECK-NEXT:    cmp r0, r1
-; CHECK-NEXT:    mov.w r0, #0
-; CHECK-NEXT:    mov.w r2, #0
-; CHECK-NEXT:    it lo
-; CHECK-NEXT:    movlo r0, #1
-; CHECK-NEXT:    it hi
-; CHECK-NEXT:    movhi r2, #1
-; CHECK-NEXT:    subs r0, r2, r0
-; CHECK-NEXT:    bx lr
+; THUMB1-LABEL: ucmp_32_32:
+; THUMB1:       @ %bb.0:
+; THUMB1-NEXT:    subs r2, r0, r1
+; THUMB1-NEXT:    sbcs r2, r2
+; THUMB1-NEXT:    cmp r1, r0
+; THUMB1-NEXT:    sbcs r1, r1
+; THUMB1-NEXT:    subs r0, r2, r1
+; THUMB1-NEXT:    bx lr
+;
+; THUMB2-LABEL: ucmp_32_32:
+; THUMB2:       @ %bb.0:
+; THUMB2-NEXT:    subs r0, r0, r1
+; THUMB2-NEXT:    it hi
+; THUMB2-NEXT:    movhi r0, #1
+; THUMB2-NEXT:    it lo
+; THUMB2-NEXT:    movlo.w r0, #-1
+; THUMB2-NEXT:    bx lr
   %1 = call i32 @llvm.ucmp(i32 %x, i32 %y)
   ret i32 %1
 }
 
 define i32 @ucmp_32_64(i64 %x, i64 %y) nounwind {
-; CHECK-LABEL: ucmp_32_64:
-; CHECK:       @ %bb.0:
-; CHECK-NEXT:    subs.w r12, r0, r2
-; CHECK-NEXT:    mov.w r9, #0
-; CHECK-NEXT:    sbcs.w r12, r1, r3
-; CHECK-NEXT:    mov.w r12, #0
-; CHECK-NEXT:    it lo
-; CHECK-NEXT:    movlo.w r12, #1
-; CHECK-NEXT:    subs r0, r2, r0
-; CHECK-NEXT:    sbcs.w r0, r3, r1
-; CHECK-NEXT:    it lo
-; CHECK-NEXT:    movlo.w r9, #1
-; CHECK-NEXT:    sub.w r0, r9, r12
-; CHECK-NEXT:    bx lr
+; THUMB1-LABEL: ucmp_32_64:
+; THUMB1:       @ %bb.0:
+; THUMB1-NEXT:    .save {r4, r5, r6, lr}
+; THUMB1-NEXT:    push {r4, r5, r6, lr}
+; THUMB1-NEXT:    movs r4, #1
+; THUMB1-NEXT:    movs r5, #0
+; THUMB1-NEXT:    subs r6, r0, r2
+; THUMB1-NEXT:    mov r6, r1
+; THUMB1-NEXT:    sbcs r6, r3
+; THUMB1-NEXT:    mov r6, r4
+; THUMB1-NEXT:    blo .LBB6_2
+; THUMB1-NEXT:  @ %bb.1:
+; THUMB1-NEXT:    mov r6, r5
+; THUMB1-NEXT:  .LBB6_2:
+; THUMB1-NEXT:    subs r0, r2, r0
+; THUMB1-NEXT:    sbcs r3, r1
+; THUMB1-NEXT:    blo .LBB6_4
+; THUMB1-NEXT:  @ %bb.3:
+; THUMB1-NEXT:    mov r4, r5
+; THUMB1-NEXT:  .LBB6_4:
+; THUMB1-NEXT:    subs r0, r4, r6
+; THUMB1-NEXT:    pop {r4, r5, r6, pc}
+;
+; THUMB2-LABEL: ucmp_32_64:
+; THUMB2:       @ %bb.0:
+; THUMB2-NEXT:    subs.w r12, r0, r2
+; THUMB2-NEXT:    mov.w r9, #0
+; THUMB2-NEXT:    sbcs.w r12, r1, r3
+; THUMB2-NEXT:    mov.w r12, #0
+; THUMB2-NEXT:    it lo
+; THUMB2-NEXT:    movlo.w r12, #1
+; THUMB2-NEXT:    subs r0, r2, r0
+; THUMB2-NEXT:    sbcs.w r0, r3, r1
+; THUMB2-NEXT:    it lo
+; THUMB2-NEXT:    movlo.w r9, #1
+; THUMB2-NEXT:    sub.w r0, r9, r12
+; THUMB2-NEXT:    bx lr
   %1 = call i32 @llvm.ucmp(i64 %x, i64 %y)
   ret i32 %1
 }
 
 define i64 @ucmp_64_64(i64 %x, i64 %y) nounwind {
-; CHECK-LABEL: ucmp_64_64:
-; CHECK:       @ %bb.0:
-; CHECK-NEXT:    subs.w r12, r0, r2
-; CHECK-NEXT:    mov.w r9, #0
-; CHECK-NEXT:    sbcs.w r12, r1, r3
-; CHECK-NEXT:    mov.w r12, #0
-; CHECK-NEXT:    it lo
-; CHECK-NEXT:    movlo.w r12, #1
-; CHECK-NEXT:    subs r0, r2, r0
-; CHECK-NEXT:    sbcs.w r0, r3, r1
-; CHECK-NEXT:    it lo
-; CHECK-NEXT:    movlo.w r9, #1
-; CHECK-NEXT:    sub.w r0, r9, r12
-; CHECK-NEXT:    asrs r1, r0, #31
-; CHECK-NEXT:    bx lr
+; THUMB1-LABEL: ucmp_64_64:
+; THUMB1:       @ %bb.0:
+; THUMB1-NEXT:    .save {r4, r5, r6, lr}
+; THUMB1-NEXT:    push {r4, r5, r6, lr}
+; THUMB1-NEXT:    movs r4, #1
+; THUMB1-NEXT:    movs r5, #0
+; THUMB1-NEXT:    subs r6, r0, r2
+; THUMB1-NEXT:    mov r6, r1
+; THUMB1-NEXT:    sbcs r6, r3
+; THUMB1-NEXT:    mov r6, r4
+; THUMB1-NEXT:    blo .LBB7_2
+; THUMB1-NEXT:  @ %bb.1:
+; THUMB1-NEXT:    mov r6, r5
+; THUMB1-NEXT:  .LBB7_2:
+; THUMB1-NEXT:    subs r0, r2, r0
+; THUMB1-NEXT:    sbcs r3, r1
+; THUMB1-NEXT:    blo .LBB7_4
+; THUMB1-NEXT:  @ %bb.3:
+; THUMB1-NEXT:    mov r4, r5
+; THUMB1-NEXT:  .LBB7_4:
+; THUMB1-NEXT:    subs r0, r4, r6
+; THUMB1-NEXT:    asrs r1, r0, #31
+; THUMB1-NEXT:    pop {r4, r5, r6, pc}
+;
+; THUMB2-LABEL: ucmp_64_64:
+; THUMB2:       @ %bb.0:
+; THUMB2-NEXT:    subs.w r12, r0, r2
+; THUMB2-NEXT:    mov.w r9, #0
+; THUMB2-NEXT:    sbcs.w r12, r1, r3
+; THUMB2-NEXT:    mov.w r12, #0
+; THUMB2-NEXT:    it lo
+; THUMB2-NEXT:    movlo.w r12, #1
+; THUMB2-NEXT:    subs r0, r2, r0
+; THUMB2-NEXT:    sbcs.w r0, r3, r1
+; THUMB2-NEXT:    it lo
+; THUMB2-NEXT:    movlo.w r9, #1
+; THUMB2-NEXT:    sub.w r0, r9, r12
+; THUMB2-NEXT:    asrs r1, r0, #31
+; THUMB2-NEXT:    bx lr
   %1 = call i64 @llvm.ucmp(i64 %x, i64 %y)
   ret i64 %1
 }

>From c41c94ea8fc46d68702f4895a67b4a4caa7415ad Mon Sep 17 00:00:00 2001
From: Rose <gfunni234 at gmail.com>
Date: Tue, 22 Jul 2025 18:46:42 -0400
Subject: [PATCH 3/9] [ARM] shouldExpandCmpUsingSelects should be true for ARM

Because this is what we are doing, this is for the sake of cost calculations even though this is manually lowered via asm.
---
 llvm/lib/Target/ARM/ARMISelLowering.cpp |  10 +-
 llvm/lib/Target/ARM/ARMISelLowering.h   |   2 +
 llvm/test/CodeGen/Thumb/scmp.ll         | 428 +++++++++++++++++++++---
 llvm/test/CodeGen/Thumb/ucmp.ll         |  86 +++++
 4 files changed, 479 insertions(+), 47 deletions(-)

diff --git a/llvm/lib/Target/ARM/ARMISelLowering.cpp b/llvm/lib/Target/ARM/ARMISelLowering.cpp
index 55fd9c637c33f..77a024f449b92 100644
--- a/llvm/lib/Target/ARM/ARMISelLowering.cpp
+++ b/llvm/lib/Target/ARM/ARMISelLowering.cpp
@@ -802,9 +802,11 @@ ARMTargetLowering::ARMTargetLowering(const TargetMachine &TM_,
     setOperationAction(ISD::BSWAP, VT, Expand);
   }
 
-  if (!Subtarget->isThumb1Only())
+  if (!Subtarget->isThumb1Only() && !Subtarget->hasMVEIntegerOps())
     setOperationAction(ISD::SCMP, MVT::i32, Custom);
-  setOperationAction(ISD::UCMP, MVT::i32, Custom);
+
+  if (!Subtarget->hasMVEIntegerOps())
+    setOperationAction(ISD::UCMP, MVT::i32, Custom);
 
   setOperationAction(ISD::ConstantFP, MVT::f32, Custom);
   setOperationAction(ISD::ConstantFP, MVT::f64, Custom);
@@ -1632,6 +1634,10 @@ bool ARMTargetLowering::useSoftFloat() const {
   return Subtarget->useSoftFloat();
 }
 
+bool ARMTargetLowering::shouldExpandCmpUsingSelects(EVT VT) const {
+  return (!Subtarget->isThumb1Only() && VT.getSizeInBits() <= 32);
+}
+
 // FIXME: It might make sense to define the representative register class as the
 // nearest super-register that has a non-null superset. For example, DPR_VFP2 is
 // a super-register of SPR, and DPR is a superset if DPR_VFP2. Consequently,
diff --git a/llvm/lib/Target/ARM/ARMISelLowering.h b/llvm/lib/Target/ARM/ARMISelLowering.h
index 1cb7edd041b32..f3b132da7b946 100644
--- a/llvm/lib/Target/ARM/ARMISelLowering.h
+++ b/llvm/lib/Target/ARM/ARMISelLowering.h
@@ -607,6 +607,8 @@ class VectorType;
 
     bool preferZeroCompareBranch() const override { return true; }
 
+    bool shouldExpandCmpUsingSelects(EVT VT) const override;
+
     bool isMaskAndCmp0FoldingBeneficial(const Instruction &AndI) const override;
 
     bool hasAndNotCompare(SDValue V) const override {
diff --git a/llvm/test/CodeGen/Thumb/scmp.ll b/llvm/test/CodeGen/Thumb/scmp.ll
index be41f8f923f1e..ba0cc0ecb3586 100644
--- a/llvm/test/CodeGen/Thumb/scmp.ll
+++ b/llvm/test/CodeGen/Thumb/scmp.ll
@@ -1,41 +1,130 @@
 ; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 5
-; RUN: llc -mtriple=thumbv7-apple-darwin %s -o - | FileCheck %s
+; RUN: llc -mtriple=thumbv6m-eabi %s -o - | FileCheck %s -check-prefix=THUMB1
+; RUN: llc -mtriple=thumbv7-apple-darwin %s -o - | FileCheck %s -check-prefix=THUMB2
+; RUN: llc -mtriple thumbv8.1m.main-none-eabi -mattr=+mve,+lob -o - %s | FileCheck %s --check-prefix=V81M
 
 define i8 @scmp_8_8(i8 signext %x, i8 signext %y) nounwind {
-; CHECK-LABEL: scmp_8_8:
-; CHECK:       @ %bb.0:
-; CHECK-NEXT:    subs r0, r0, r1
-; CHECK-NEXT:    it gt
-; CHECK-NEXT:    movgt r0, #1
-; CHECK-NEXT:    it lt
-; CHECK-NEXT:    movlt.w r0, #-1
-; CHECK-NEXT:    bx lr
+; THUMB1-LABEL: scmp_8_8:
+; THUMB1:       @ %bb.0:
+; THUMB1-NEXT:    movs r2, #1
+; THUMB1-NEXT:    movs r3, #0
+; THUMB1-NEXT:    cmp r0, r1
+; THUMB1-NEXT:    mov r0, r2
+; THUMB1-NEXT:    bge .LBB0_3
+; THUMB1-NEXT:  @ %bb.1:
+; THUMB1-NEXT:    ble .LBB0_4
+; THUMB1-NEXT:  .LBB0_2:
+; THUMB1-NEXT:    subs r0, r2, r0
+; THUMB1-NEXT:    bx lr
+; THUMB1-NEXT:  .LBB0_3:
+; THUMB1-NEXT:    mov r0, r3
+; THUMB1-NEXT:    bgt .LBB0_2
+; THUMB1-NEXT:  .LBB0_4:
+; THUMB1-NEXT:    mov r2, r3
+; THUMB1-NEXT:    subs r0, r2, r0
+; THUMB1-NEXT:    bx lr
+;
+; THUMB2-LABEL: scmp_8_8:
+; THUMB2:       @ %bb.0:
+; THUMB2-NEXT:    subs r0, r0, r1
+; THUMB2-NEXT:    it gt
+; THUMB2-NEXT:    movgt r0, #1
+; THUMB2-NEXT:    it lt
+; THUMB2-NEXT:    movlt.w r0, #-1
+; THUMB2-NEXT:    bx lr
+;
+; V81M-LABEL: scmp_8_8:
+; V81M:       @ %bb.0:
+; V81M-NEXT:    subs r0, r0, r1
+; V81M-NEXT:    it gt
+; V81M-NEXT:    movgt r0, #1
+; V81M-NEXT:    it lt
+; V81M-NEXT:    movlt.w r0, #-1
+; V81M-NEXT:    bx lr
   %1 = call i8 @llvm.scmp(i8 %x, i8 %y)
   ret i8 %1
 }
 
 define i8 @scmp_8_16(i16 signext %x, i16 signext %y) nounwind {
-; CHECK-LABEL: scmp_8_16:
-; CHECK:       @ %bb.0:
-; CHECK-NEXT:    subs r0, r0, r1
-; CHECK-NEXT:    it gt
-; CHECK-NEXT:    movgt r0, #1
-; CHECK-NEXT:    it lt
-; CHECK-NEXT:    movlt.w r0, #-1
-; CHECK-NEXT:    bx lr
+; THUMB1-LABEL: scmp_8_16:
+; THUMB1:       @ %bb.0:
+; THUMB1-NEXT:    movs r2, #1
+; THUMB1-NEXT:    movs r3, #0
+; THUMB1-NEXT:    cmp r0, r1
+; THUMB1-NEXT:    mov r0, r2
+; THUMB1-NEXT:    bge .LBB1_3
+; THUMB1-NEXT:  @ %bb.1:
+; THUMB1-NEXT:    ble .LBB1_4
+; THUMB1-NEXT:  .LBB1_2:
+; THUMB1-NEXT:    subs r0, r2, r0
+; THUMB1-NEXT:    bx lr
+; THUMB1-NEXT:  .LBB1_3:
+; THUMB1-NEXT:    mov r0, r3
+; THUMB1-NEXT:    bgt .LBB1_2
+; THUMB1-NEXT:  .LBB1_4:
+; THUMB1-NEXT:    mov r2, r3
+; THUMB1-NEXT:    subs r0, r2, r0
+; THUMB1-NEXT:    bx lr
+;
+; THUMB2-LABEL: scmp_8_16:
+; THUMB2:       @ %bb.0:
+; THUMB2-NEXT:    subs r0, r0, r1
+; THUMB2-NEXT:    it gt
+; THUMB2-NEXT:    movgt r0, #1
+; THUMB2-NEXT:    it lt
+; THUMB2-NEXT:    movlt.w r0, #-1
+; THUMB2-NEXT:    bx lr
+;
+; V81M-LABEL: scmp_8_16:
+; V81M:       @ %bb.0:
+; V81M-NEXT:    subs r0, r0, r1
+; V81M-NEXT:    it gt
+; V81M-NEXT:    movgt r0, #1
+; V81M-NEXT:    it lt
+; V81M-NEXT:    movlt.w r0, #-1
+; V81M-NEXT:    bx lr
   %1 = call i8 @llvm.scmp(i16 %x, i16 %y)
   ret i8 %1
 }
 
 define i8 @scmp_8_32(i32 %x, i32 %y) nounwind {
-; CHECK-LABEL: scmp_8_32:
-; CHECK:       @ %bb.0:
-; CHECK-NEXT:    subs r0, r0, r1
-; CHECK-NEXT:    it gt
-; CHECK-NEXT:    movgt r0, #1
-; CHECK-NEXT:    it lt
-; CHECK-NEXT:    movlt.w r0, #-1
-; CHECK-NEXT:    bx lr
+; THUMB1-LABEL: scmp_8_32:
+; THUMB1:       @ %bb.0:
+; THUMB1-NEXT:    movs r2, #1
+; THUMB1-NEXT:    movs r3, #0
+; THUMB1-NEXT:    cmp r0, r1
+; THUMB1-NEXT:    mov r0, r2
+; THUMB1-NEXT:    bge .LBB2_3
+; THUMB1-NEXT:  @ %bb.1:
+; THUMB1-NEXT:    ble .LBB2_4
+; THUMB1-NEXT:  .LBB2_2:
+; THUMB1-NEXT:    subs r0, r2, r0
+; THUMB1-NEXT:    bx lr
+; THUMB1-NEXT:  .LBB2_3:
+; THUMB1-NEXT:    mov r0, r3
+; THUMB1-NEXT:    bgt .LBB2_2
+; THUMB1-NEXT:  .LBB2_4:
+; THUMB1-NEXT:    mov r2, r3
+; THUMB1-NEXT:    subs r0, r2, r0
+; THUMB1-NEXT:    bx lr
+;
+; THUMB2-LABEL: scmp_8_32:
+; THUMB2:       @ %bb.0:
+; THUMB2-NEXT:    subs r0, r0, r1
+; THUMB2-NEXT:    it gt
+; THUMB2-NEXT:    movgt r0, #1
+; THUMB2-NEXT:    it lt
+; THUMB2-NEXT:    movlt.w r0, #-1
+; THUMB2-NEXT:    bx lr
+;
+; V81M-LABEL: scmp_8_32:
+; V81M:       @ %bb.0:
+; V81M-NEXT:    subs r0, r0, r1
+; V81M-NEXT:    it gt
+; V81M-NEXT:    movgt r0, #1
+; V81M-NEXT:    it lt
+; V81M-NEXT:    movlt.w r0, #-1
+; V81M-NEXT:    bx lr
   %1 = call i8 @llvm.scmp(i32 %x, i32 %y)
   ret i8 %1
 }
@@ -43,18 +132,54 @@ define i8 @scmp_8_32(i32 %x, i32 %y) nounwind {
 define i8 @scmp_8_64(i64 %x, i64 %y) nounwind {
 ; CHECK-LABEL: scmp_8_64:
 ; CHECK:       @ %bb.0:
-; CHECK-NEXT:    subs.w r12, r0, r2
-; CHECK-NEXT:    mov.w r9, #0
-; CHECK-NEXT:    sbcs.w r12, r1, r3
-; CHECK-NEXT:    mov.w r12, #0
-; CHECK-NEXT:    it lt
-; CHECK-NEXT:    movlt.w r12, #1
-; CHECK-NEXT:    subs r0, r2, r0
-; CHECK-NEXT:    sbcs.w r0, r3, r1
-; CHECK-NEXT:    it lt
-; CHECK-NEXT:    movlt.w r9, #1
-; CHECK-NEXT:    sub.w r0, r9, r12
-; CHECK-NEXT:    bx lr
+; THUMB1-LABEL: scmp_8_64:
+; THUMB1:       @ %bb.0:
+; THUMB1-NEXT:    .save {r4, r5, r6, lr}
+; THUMB1-NEXT:    push {r4, r5, r6, lr}
+; THUMB1-NEXT:    movs r4, #1
+; THUMB1-NEXT:    movs r5, #0
+; THUMB1-NEXT:    subs r6, r0, r2
+; THUMB1-NEXT:    mov r6, r1
+; THUMB1-NEXT:    sbcs r6, r3
+; THUMB1-NEXT:    mov r6, r4
+; THUMB1-NEXT:    blt .LBB3_2
+; THUMB1-NEXT:  @ %bb.1:
+; THUMB1-NEXT:    mov r6, r5
+; THUMB1-NEXT:  .LBB3_2:
+; THUMB1-NEXT:    subs r0, r2, r0
+; THUMB1-NEXT:    sbcs r3, r1
+; THUMB1-NEXT:    blt .LBB3_4
+; THUMB1-NEXT:  @ %bb.3:
+; THUMB1-NEXT:    mov r4, r5
+; THUMB1-NEXT:  .LBB3_4:
+; THUMB1-NEXT:    subs r0, r4, r6
+; THUMB1-NEXT:    pop {r4, r5, r6, pc}
+;
+; THUMB2-LABEL: scmp_8_64:
+; THUMB2:       @ %bb.0:
+; THUMB2-NEXT:    subs.w r12, r0, r2
+; THUMB2-NEXT:    mov.w r9, #0
+; THUMB2-NEXT:    sbcs.w r12, r1, r3
+; THUMB2-NEXT:    mov.w r12, #0
+; THUMB2-NEXT:    it lt
+; THUMB2-NEXT:    movlt.w r12, #1
+; THUMB2-NEXT:    subs r0, r2, r0
+; THUMB2-NEXT:    sbcs.w r0, r3, r1
+; THUMB2-NEXT:    it lt
+; THUMB2-NEXT:    movlt.w r9, #1
+; THUMB2-NEXT:    sub.w r0, r9, r12
+; THUMB2-NEXT:    bx lr
+;
+; V81M-LABEL: scmp_8_64:
+; V81M:       @ %bb.0:
+; V81M-NEXT:    subs.w r12, r0, r2
+; V81M-NEXT:    sbcs.w r12, r1, r3
+; V81M-NEXT:    cset r12, lt
+; V81M-NEXT:    subs r0, r2, r0
+; V81M-NEXT:    sbcs.w r0, r3, r1
+; V81M-NEXT:    cset r0, lt
+; V81M-NEXT:    sub.w r0, r0, r12
+; V81M-NEXT:    bx lr
   %1 = call i8 @llvm.scmp(i64 %x, i64 %y)
   ret i8 %1
 }
@@ -82,19 +207,133 @@ define i8 @scmp_8_128(i128 %x, i128 %y) nounwind {
 ; CHECK-NEXT:    movlt r5, #1
 ; CHECK-NEXT:    subs r0, r5, r6
 ; CHECK-NEXT:    pop {r4, r5, r6, pc}
+; THUMB1-LABEL: scmp_8_128:
+; THUMB1:       @ %bb.0:
+; THUMB1-NEXT:    .save {r4, r5, r6, r7, lr}
+; THUMB1-NEXT:    push {r4, r5, r6, r7, lr}
+; THUMB1-NEXT:    .pad #20
+; THUMB1-NEXT:    sub sp, #20
+; THUMB1-NEXT:    str r3, [sp, #16] @ 4-byte Spill
+; THUMB1-NEXT:    movs r3, #1
+; THUMB1-NEXT:    str r3, [sp] @ 4-byte Spill
+; THUMB1-NEXT:    movs r3, #0
+; THUMB1-NEXT:    str r3, [sp, #12] @ 4-byte Spill
+; THUMB1-NEXT:    ldr r6, [sp, #52]
+; THUMB1-NEXT:    add r7, sp, #40
+; THUMB1-NEXT:    ldm r7, {r3, r5, r7}
+; THUMB1-NEXT:    subs r4, r0, r3
+; THUMB1-NEXT:    str r1, [sp, #4] @ 4-byte Spill
+; THUMB1-NEXT:    mov r4, r1
+; THUMB1-NEXT:    ldr r1, [sp] @ 4-byte Reload
+; THUMB1-NEXT:    sbcs r4, r5
+; THUMB1-NEXT:    str r2, [sp, #8] @ 4-byte Spill
+; THUMB1-NEXT:    mov r4, r2
+; THUMB1-NEXT:    sbcs r4, r7
+; THUMB1-NEXT:    ldr r4, [sp, #16] @ 4-byte Reload
+; THUMB1-NEXT:    sbcs r4, r6
+; THUMB1-NEXT:    mov r2, r1
+; THUMB1-NEXT:    blt .LBB4_2
+; THUMB1-NEXT:  @ %bb.1:
+; THUMB1-NEXT:    ldr r2, [sp, #12] @ 4-byte Reload
+; THUMB1-NEXT:  .LBB4_2:
+; THUMB1-NEXT:    subs r0, r3, r0
+; THUMB1-NEXT:    ldr r0, [sp, #4] @ 4-byte Reload
+; THUMB1-NEXT:    sbcs r5, r0
+; THUMB1-NEXT:    ldr r0, [sp, #8] @ 4-byte Reload
+; THUMB1-NEXT:    sbcs r7, r0
+; THUMB1-NEXT:    ldr r0, [sp, #16] @ 4-byte Reload
+; THUMB1-NEXT:    sbcs r6, r0
+; THUMB1-NEXT:    blt .LBB4_4
+; THUMB1-NEXT:  @ %bb.3:
+; THUMB1-NEXT:    ldr r1, [sp, #12] @ 4-byte Reload
+; THUMB1-NEXT:  .LBB4_4:
+; THUMB1-NEXT:    subs r0, r1, r2
+; THUMB1-NEXT:    add sp, #20
+; THUMB1-NEXT:    pop {r4, r5, r6, r7, pc}
+;
+; THUMB2-LABEL: scmp_8_128:
+; THUMB2:       @ %bb.0:
+; THUMB2-NEXT:    push {r4, r5, r6, lr}
+; THUMB2-NEXT:    add.w lr, sp, #16
+; THUMB2-NEXT:    ldr r4, [sp, #28]
+; THUMB2-NEXT:    movs r5, #0
+; THUMB2-NEXT:    ldm.w lr, {r9, r12, lr}
+; THUMB2-NEXT:    subs.w r6, r0, r9
+; THUMB2-NEXT:    sbcs.w r6, r1, r12
+; THUMB2-NEXT:    sbcs.w r6, r2, lr
+; THUMB2-NEXT:    sbcs.w r6, r3, r4
+; THUMB2-NEXT:    mov.w r6, #0
+; THUMB2-NEXT:    it lt
+; THUMB2-NEXT:    movlt r6, #1
+; THUMB2-NEXT:    subs.w r0, r9, r0
+; THUMB2-NEXT:    sbcs.w r0, r12, r1
+; THUMB2-NEXT:    sbcs.w r0, lr, r2
+; THUMB2-NEXT:    sbcs.w r0, r4, r3
+; THUMB2-NEXT:    it lt
+; THUMB2-NEXT:    movlt r5, #1
+; THUMB2-NEXT:    subs r0, r5, r6
+; THUMB2-NEXT:    pop {r4, r5, r6, pc}
+;
+; V81M-LABEL: scmp_8_128:
+; V81M:       @ %bb.0:
+; V81M-NEXT:    .save {r4, r5, r6, lr}
+; V81M-NEXT:    push {r4, r5, r6, lr}
+; V81M-NEXT:    ldrd r5, r4, [sp, #16]
+; V81M-NEXT:    ldrd lr, r12, [sp, #24]
+; V81M-NEXT:    subs r6, r0, r5
+; V81M-NEXT:    sbcs.w r6, r1, r4
+; V81M-NEXT:    sbcs.w r6, r2, lr
+; V81M-NEXT:    sbcs.w r6, r3, r12
+; V81M-NEXT:    cset r6, lt
+; V81M-NEXT:    subs r0, r5, r0
+; V81M-NEXT:    sbcs.w r0, r4, r1
+; V81M-NEXT:    sbcs.w r0, lr, r2
+; V81M-NEXT:    sbcs.w r0, r12, r3
+; V81M-NEXT:    cset r0, lt
+; V81M-NEXT:    subs r0, r0, r6
+; V81M-NEXT:    pop {r4, r5, r6, pc}
   %1 = call i8 @llvm.scmp(i128 %x, i128 %y)
   ret i8 %1
 }
 
 define i32 @scmp_32_32(i32 %x, i32 %y) nounwind {
-; CHECK-LABEL: scmp_32_32:
-; CHECK:       @ %bb.0:
-; CHECK-NEXT:    subs r0, r0, r1
-; CHECK-NEXT:    it gt
-; CHECK-NEXT:    movgt r0, #1
-; CHECK-NEXT:    it lt
-; CHECK-NEXT:    movlt.w r0, #-1
-; CHECK-NEXT:    bx lr
+; THUMB1-LABEL: scmp_32_32:
+; THUMB1:       @ %bb.0:
+; THUMB1-NEXT:    movs r2, #1
+; THUMB1-NEXT:    movs r3, #0
+; THUMB1-NEXT:    cmp r0, r1
+; THUMB1-NEXT:    mov r0, r2
+; THUMB1-NEXT:    bge .LBB5_3
+; THUMB1-NEXT:  @ %bb.1:
+; THUMB1-NEXT:    ble .LBB5_4
+; THUMB1-NEXT:  .LBB5_2:
+; THUMB1-NEXT:    subs r0, r2, r0
+; THUMB1-NEXT:    bx lr
+; THUMB1-NEXT:  .LBB5_3:
+; THUMB1-NEXT:    mov r0, r3
+; THUMB1-NEXT:    bgt .LBB5_2
+; THUMB1-NEXT:  .LBB5_4:
+; THUMB1-NEXT:    mov r2, r3
+; THUMB1-NEXT:    subs r0, r2, r0
+; THUMB1-NEXT:    bx lr
+;
+; THUMB2-LABEL: scmp_32_32:
+; THUMB2:       @ %bb.0:
+; THUMB2-NEXT:    subs r0, r0, r1
+; THUMB2-NEXT:    it gt
+; THUMB2-NEXT:    movgt r0, #1
+; THUMB2-NEXT:    it lt
+; THUMB2-NEXT:    movlt.w r0, #-1
+; THUMB2-NEXT:    bx lr
+;
+; V81M-LABEL: scmp_32_32:
+; V81M:       @ %bb.0:
+; V81M-NEXT:    subs r0, r0, r1
+; V81M-NEXT:    it gt
+; V81M-NEXT:    movgt r0, #1
+; V81M-NEXT:    it lt
+; V81M-NEXT:    movlt.w r0, #-1
+; V81M-NEXT:    bx lr
   %1 = call i32 @llvm.scmp(i32 %x, i32 %y)
   ret i32 %1
 }
@@ -114,6 +353,54 @@ define i32 @scmp_32_64(i64 %x, i64 %y) nounwind {
 ; CHECK-NEXT:    movlt.w r9, #1
 ; CHECK-NEXT:    sub.w r0, r9, r12
 ; CHECK-NEXT:    bx lr
+; THUMB1-LABEL: scmp_32_64:
+; THUMB1:       @ %bb.0:
+; THUMB1-NEXT:    .save {r4, r5, r6, lr}
+; THUMB1-NEXT:    push {r4, r5, r6, lr}
+; THUMB1-NEXT:    movs r4, #1
+; THUMB1-NEXT:    movs r5, #0
+; THUMB1-NEXT:    subs r6, r0, r2
+; THUMB1-NEXT:    mov r6, r1
+; THUMB1-NEXT:    sbcs r6, r3
+; THUMB1-NEXT:    mov r6, r4
+; THUMB1-NEXT:    blt .LBB6_2
+; THUMB1-NEXT:  @ %bb.1:
+; THUMB1-NEXT:    mov r6, r5
+; THUMB1-NEXT:  .LBB6_2:
+; THUMB1-NEXT:    subs r0, r2, r0
+; THUMB1-NEXT:    sbcs r3, r1
+; THUMB1-NEXT:    blt .LBB6_4
+; THUMB1-NEXT:  @ %bb.3:
+; THUMB1-NEXT:    mov r4, r5
+; THUMB1-NEXT:  .LBB6_4:
+; THUMB1-NEXT:    subs r0, r4, r6
+; THUMB1-NEXT:    pop {r4, r5, r6, pc}
+;
+; THUMB2-LABEL: scmp_32_64:
+; THUMB2:       @ %bb.0:
+; THUMB2-NEXT:    subs.w r12, r0, r2
+; THUMB2-NEXT:    mov.w r9, #0
+; THUMB2-NEXT:    sbcs.w r12, r1, r3
+; THUMB2-NEXT:    mov.w r12, #0
+; THUMB2-NEXT:    it lt
+; THUMB2-NEXT:    movlt.w r12, #1
+; THUMB2-NEXT:    subs r0, r2, r0
+; THUMB2-NEXT:    sbcs.w r0, r3, r1
+; THUMB2-NEXT:    it lt
+; THUMB2-NEXT:    movlt.w r9, #1
+; THUMB2-NEXT:    sub.w r0, r9, r12
+; THUMB2-NEXT:    bx lr
+;
+; V81M-LABEL: scmp_32_64:
+; V81M:       @ %bb.0:
+; V81M-NEXT:    subs.w r12, r0, r2
+; V81M-NEXT:    sbcs.w r12, r1, r3
+; V81M-NEXT:    cset r12, lt
+; V81M-NEXT:    subs r0, r2, r0
+; V81M-NEXT:    sbcs.w r0, r3, r1
+; V81M-NEXT:    cset r0, lt
+; V81M-NEXT:    sub.w r0, r0, r12
+; V81M-NEXT:    bx lr
   %1 = call i32 @llvm.scmp(i64 %x, i64 %y)
   ret i32 %1
 }
@@ -134,6 +421,57 @@ define i64 @scmp_64_64(i64 %x, i64 %y) nounwind {
 ; CHECK-NEXT:    sub.w r0, r9, r12
 ; CHECK-NEXT:    asrs r1, r0, #31
 ; CHECK-NEXT:    bx lr
+; THUMB1-LABEL: scmp_64_64:
+; THUMB1:       @ %bb.0:
+; THUMB1-NEXT:    .save {r4, r5, r6, lr}
+; THUMB1-NEXT:    push {r4, r5, r6, lr}
+; THUMB1-NEXT:    movs r4, #1
+; THUMB1-NEXT:    movs r5, #0
+; THUMB1-NEXT:    subs r6, r0, r2
+; THUMB1-NEXT:    mov r6, r1
+; THUMB1-NEXT:    sbcs r6, r3
+; THUMB1-NEXT:    mov r6, r4
+; THUMB1-NEXT:    blt .LBB7_2
+; THUMB1-NEXT:  @ %bb.1:
+; THUMB1-NEXT:    mov r6, r5
+; THUMB1-NEXT:  .LBB7_2:
+; THUMB1-NEXT:    subs r0, r2, r0
+; THUMB1-NEXT:    sbcs r3, r1
+; THUMB1-NEXT:    blt .LBB7_4
+; THUMB1-NEXT:  @ %bb.3:
+; THUMB1-NEXT:    mov r4, r5
+; THUMB1-NEXT:  .LBB7_4:
+; THUMB1-NEXT:    subs r0, r4, r6
+; THUMB1-NEXT:    asrs r1, r0, #31
+; THUMB1-NEXT:    pop {r4, r5, r6, pc}
+;
+; THUMB2-LABEL: scmp_64_64:
+; THUMB2:       @ %bb.0:
+; THUMB2-NEXT:    subs.w r12, r0, r2
+; THUMB2-NEXT:    mov.w r9, #0
+; THUMB2-NEXT:    sbcs.w r12, r1, r3
+; THUMB2-NEXT:    mov.w r12, #0
+; THUMB2-NEXT:    it lt
+; THUMB2-NEXT:    movlt.w r12, #1
+; THUMB2-NEXT:    subs r0, r2, r0
+; THUMB2-NEXT:    sbcs.w r0, r3, r1
+; THUMB2-NEXT:    it lt
+; THUMB2-NEXT:    movlt.w r9, #1
+; THUMB2-NEXT:    sub.w r0, r9, r12
+; THUMB2-NEXT:    asrs r1, r0, #31
+; THUMB2-NEXT:    bx lr
+;
+; V81M-LABEL: scmp_64_64:
+; V81M:       @ %bb.0:
+; V81M-NEXT:    subs.w r12, r0, r2
+; V81M-NEXT:    sbcs.w r12, r1, r3
+; V81M-NEXT:    cset r12, lt
+; V81M-NEXT:    subs r0, r2, r0
+; V81M-NEXT:    sbcs.w r0, r3, r1
+; V81M-NEXT:    cset r0, lt
+; V81M-NEXT:    sub.w r0, r0, r12
+; V81M-NEXT:    asrs r1, r0, #31
+; V81M-NEXT:    bx lr
   %1 = call i64 @llvm.scmp(i64 %x, i64 %y)
   ret i64 %1
 }
diff --git a/llvm/test/CodeGen/Thumb/ucmp.ll b/llvm/test/CodeGen/Thumb/ucmp.ll
index 25cf98cb343df..cce15afaeb3ab 100644
--- a/llvm/test/CodeGen/Thumb/ucmp.ll
+++ b/llvm/test/CodeGen/Thumb/ucmp.ll
@@ -1,6 +1,7 @@
 ; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 5
 ; RUN: llc -mtriple=thumbv6m-eabi %s -o - | FileCheck %s -check-prefix=THUMB1
 ; RUN: llc -mtriple=thumbv7-apple-darwin %s -o - | FileCheck %s -check-prefix=THUMB2
+; RUN: llc -mtriple thumbv8.1m.main-none-eabi -mattr=+mve,+lob -o - %s | FileCheck %s --check-prefix=V81M
 
 define i8 @ucmp_8_8(i8 zeroext %x, i8 zeroext %y) nounwind {
 ; THUMB1-LABEL: ucmp_8_8:
@@ -20,6 +21,14 @@ define i8 @ucmp_8_8(i8 zeroext %x, i8 zeroext %y) nounwind {
 ; THUMB2-NEXT:    it lo
 ; THUMB2-NEXT:    movlo.w r0, #-1
 ; THUMB2-NEXT:    bx lr
+;
+; V81M-LABEL: ucmp_8_8:
+; V81M:       @ %bb.0:
+; V81M-NEXT:    cmp r0, r1
+; V81M-NEXT:    cset r0, hi
+; V81M-NEXT:    it lo
+; V81M-NEXT:    movlo.w r0, #-1
+; V81M-NEXT:    bx lr
   %1 = call i8 @llvm.ucmp(i8 %x, i8 %y)
   ret i8 %1
 }
@@ -42,6 +51,14 @@ define i8 @ucmp_8_16(i16 zeroext %x, i16 zeroext %y) nounwind {
 ; THUMB2-NEXT:    it lo
 ; THUMB2-NEXT:    movlo.w r0, #-1
 ; THUMB2-NEXT:    bx lr
+;
+; V81M-LABEL: ucmp_8_16:
+; V81M:       @ %bb.0:
+; V81M-NEXT:    cmp r0, r1
+; V81M-NEXT:    cset r0, hi
+; V81M-NEXT:    it lo
+; V81M-NEXT:    movlo.w r0, #-1
+; V81M-NEXT:    bx lr
   %1 = call i8 @llvm.ucmp(i16 %x, i16 %y)
   ret i8 %1
 }
@@ -64,6 +81,14 @@ define i8 @ucmp_8_32(i32 %x, i32 %y) nounwind {
 ; THUMB2-NEXT:    it lo
 ; THUMB2-NEXT:    movlo.w r0, #-1
 ; THUMB2-NEXT:    bx lr
+;
+; V81M-LABEL: ucmp_8_32:
+; V81M:       @ %bb.0:
+; V81M-NEXT:    cmp r0, r1
+; V81M-NEXT:    cset r0, hi
+; V81M-NEXT:    it lo
+; V81M-NEXT:    movlo.w r0, #-1
+; V81M-NEXT:    bx lr
   %1 = call i8 @llvm.ucmp(i32 %x, i32 %y)
   ret i8 %1
 }
@@ -106,6 +131,17 @@ define i8 @ucmp_8_64(i64 %x, i64 %y) nounwind {
 ; THUMB2-NEXT:    movlo.w r9, #1
 ; THUMB2-NEXT:    sub.w r0, r9, r12
 ; THUMB2-NEXT:    bx lr
+;
+; V81M-LABEL: ucmp_8_64:
+; V81M:       @ %bb.0:
+; V81M-NEXT:    subs.w r12, r0, r2
+; V81M-NEXT:    sbcs.w r12, r1, r3
+; V81M-NEXT:    cset r12, lo
+; V81M-NEXT:    subs r0, r2, r0
+; V81M-NEXT:    sbcs.w r0, r3, r1
+; V81M-NEXT:    cset r0, lo
+; V81M-NEXT:    sub.w r0, r0, r12
+; V81M-NEXT:    bx lr
   %1 = call i8 @llvm.ucmp(i64 %x, i64 %y)
   ret i8 %1
 }
@@ -177,6 +213,25 @@ define i8 @ucmp_8_128(i128 %x, i128 %y) nounwind {
 ; THUMB2-NEXT:    movlo r5, #1
 ; THUMB2-NEXT:    subs r0, r5, r6
 ; THUMB2-NEXT:    pop {r4, r5, r6, pc}
+;
+; V81M-LABEL: ucmp_8_128:
+; V81M:       @ %bb.0:
+; V81M-NEXT:    .save {r4, r5, r6, lr}
+; V81M-NEXT:    push {r4, r5, r6, lr}
+; V81M-NEXT:    ldrd r5, r4, [sp, #16]
+; V81M-NEXT:    ldrd lr, r12, [sp, #24]
+; V81M-NEXT:    subs r6, r0, r5
+; V81M-NEXT:    sbcs.w r6, r1, r4
+; V81M-NEXT:    sbcs.w r6, r2, lr
+; V81M-NEXT:    sbcs.w r6, r3, r12
+; V81M-NEXT:    cset r6, lo
+; V81M-NEXT:    subs r0, r5, r0
+; V81M-NEXT:    sbcs.w r0, r4, r1
+; V81M-NEXT:    sbcs.w r0, lr, r2
+; V81M-NEXT:    sbcs.w r0, r12, r3
+; V81M-NEXT:    cset r0, lo
+; V81M-NEXT:    subs r0, r0, r6
+; V81M-NEXT:    pop {r4, r5, r6, pc}
   %1 = call i8 @llvm.ucmp(i128 %x, i128 %y)
   ret i8 %1
 }
@@ -199,6 +254,14 @@ define i32 @ucmp_32_32(i32 %x, i32 %y) nounwind {
 ; THUMB2-NEXT:    it lo
 ; THUMB2-NEXT:    movlo.w r0, #-1
 ; THUMB2-NEXT:    bx lr
+;
+; V81M-LABEL: ucmp_32_32:
+; V81M:       @ %bb.0:
+; V81M-NEXT:    cmp r0, r1
+; V81M-NEXT:    cset r0, hi
+; V81M-NEXT:    it lo
+; V81M-NEXT:    movlo.w r0, #-1
+; V81M-NEXT:    bx lr
   %1 = call i32 @llvm.ucmp(i32 %x, i32 %y)
   ret i32 %1
 }
@@ -241,6 +304,17 @@ define i32 @ucmp_32_64(i64 %x, i64 %y) nounwind {
 ; THUMB2-NEXT:    movlo.w r9, #1
 ; THUMB2-NEXT:    sub.w r0, r9, r12
 ; THUMB2-NEXT:    bx lr
+;
+; V81M-LABEL: ucmp_32_64:
+; V81M:       @ %bb.0:
+; V81M-NEXT:    subs.w r12, r0, r2
+; V81M-NEXT:    sbcs.w r12, r1, r3
+; V81M-NEXT:    cset r12, lo
+; V81M-NEXT:    subs r0, r2, r0
+; V81M-NEXT:    sbcs.w r0, r3, r1
+; V81M-NEXT:    cset r0, lo
+; V81M-NEXT:    sub.w r0, r0, r12
+; V81M-NEXT:    bx lr
   %1 = call i32 @llvm.ucmp(i64 %x, i64 %y)
   ret i32 %1
 }
@@ -285,6 +359,18 @@ define i64 @ucmp_64_64(i64 %x, i64 %y) nounwind {
 ; THUMB2-NEXT:    sub.w r0, r9, r12
 ; THUMB2-NEXT:    asrs r1, r0, #31
 ; THUMB2-NEXT:    bx lr
+;
+; V81M-LABEL: ucmp_64_64:
+; V81M:       @ %bb.0:
+; V81M-NEXT:    subs.w r12, r0, r2
+; V81M-NEXT:    sbcs.w r12, r1, r3
+; V81M-NEXT:    cset r12, lo
+; V81M-NEXT:    subs r0, r2, r0
+; V81M-NEXT:    sbcs.w r0, r3, r1
+; V81M-NEXT:    cset r0, lo
+; V81M-NEXT:    sub.w r0, r0, r12
+; V81M-NEXT:    asrs r1, r0, #31
+; V81M-NEXT:    bx lr
   %1 = call i64 @llvm.ucmp(i64 %x, i64 %y)
   ret i64 %1
 }

>From 089df693f7b6fe94b24b86a71793311f45df98a4 Mon Sep 17 00:00:00 2001
From: Rose <gfunni234 at gmail.com>
Date: Tue, 22 Jul 2025 21:54:06 -0400
Subject: [PATCH 4/9] Fix issues

---
 llvm/lib/Target/ARM/ARMISelLowering.cpp |  4 ++--
 llvm/test/CodeGen/Thumb/scmp.ll         | 20 ++++++++------------
 2 files changed, 10 insertions(+), 14 deletions(-)

diff --git a/llvm/lib/Target/ARM/ARMISelLowering.cpp b/llvm/lib/Target/ARM/ARMISelLowering.cpp
index 77a024f449b92..1a1f25cc7a90c 100644
--- a/llvm/lib/Target/ARM/ARMISelLowering.cpp
+++ b/llvm/lib/Target/ARM/ARMISelLowering.cpp
@@ -10675,7 +10675,7 @@ SDValue ARMTargetLowering::LowerSCMP(SDValue Op, SelectionDAG &DAG) const {
 
   // Constants for conditional moves
   SDValue One = DAG.getConstant(1, dl, MVT::i32);
-  SDValue MinusOne = DAG.getConstant(0xFFFFFFFF, dl, MVT::i32);
+  SDValue MinusOne = DAG.getAllOnesConstant(dl, MVT::i32);
 
   // movgt: if greater than, set to 1
   SDValue GTCond = DAG.getConstant(ARMCC::GT, dl, MVT::i32);
@@ -10781,7 +10781,7 @@ SDValue ARMTargetLowering::LowerUCMP(SDValue Op, SelectionDAG &DAG) const {
 
   // Constants for conditional moves
   SDValue One = DAG.getConstant(1, dl, MVT::i32);
-  SDValue MinusOne = DAG.getConstant(0xFFFFFFFF, dl, MVT::i32);
+  SDValue MinusOne = DAG.getAllOnesConstant(dl, MVT::i32);
 
   // movhi: if higher (unsigned greater than), set to 1
   SDValue HICond = DAG.getConstant(ARMCC::HI, dl, MVT::i32);
diff --git a/llvm/test/CodeGen/Thumb/scmp.ll b/llvm/test/CodeGen/Thumb/scmp.ll
index ba0cc0ecb3586..d74109347c369 100644
--- a/llvm/test/CodeGen/Thumb/scmp.ll
+++ b/llvm/test/CodeGen/Thumb/scmp.ll
@@ -35,9 +35,8 @@ define i8 @scmp_8_8(i8 signext %x, i8 signext %y) nounwind {
 ;
 ; V81M-LABEL: scmp_8_8:
 ; V81M:       @ %bb.0:
-; V81M-NEXT:    subs r0, r0, r1
-; V81M-NEXT:    it gt
-; V81M-NEXT:    movgt r0, #1
+; V81M-NEXT:    cmp r0, r1
+; V81M-NEXT:    cset r0, gt
 ; V81M-NEXT:    it lt
 ; V81M-NEXT:    movlt.w r0, #-1
 ; V81M-NEXT:    bx lr
@@ -77,9 +76,8 @@ define i8 @scmp_8_16(i16 signext %x, i16 signext %y) nounwind {
 ;
 ; V81M-LABEL: scmp_8_16:
 ; V81M:       @ %bb.0:
-; V81M-NEXT:    subs r0, r0, r1
-; V81M-NEXT:    it gt
-; V81M-NEXT:    movgt r0, #1
+; V81M-NEXT:    cmp r0, r1
+; V81M-NEXT:    cset r0, gt
 ; V81M-NEXT:    it lt
 ; V81M-NEXT:    movlt.w r0, #-1
 ; V81M-NEXT:    bx lr
@@ -119,9 +117,8 @@ define i8 @scmp_8_32(i32 %x, i32 %y) nounwind {
 ;
 ; V81M-LABEL: scmp_8_32:
 ; V81M:       @ %bb.0:
-; V81M-NEXT:    subs r0, r0, r1
-; V81M-NEXT:    it gt
-; V81M-NEXT:    movgt r0, #1
+; V81M-NEXT:    cmp r0, r1
+; V81M-NEXT:    cset r0, gt
 ; V81M-NEXT:    it lt
 ; V81M-NEXT:    movlt.w r0, #-1
 ; V81M-NEXT:    bx lr
@@ -328,9 +325,8 @@ define i32 @scmp_32_32(i32 %x, i32 %y) nounwind {
 ;
 ; V81M-LABEL: scmp_32_32:
 ; V81M:       @ %bb.0:
-; V81M-NEXT:    subs r0, r0, r1
-; V81M-NEXT:    it gt
-; V81M-NEXT:    movgt r0, #1
+; V81M-NEXT:    cmp r0, r1
+; V81M-NEXT:    cset r0, gt
 ; V81M-NEXT:    it lt
 ; V81M-NEXT:    movlt.w r0, #-1
 ; V81M-NEXT:    bx lr

>From 1cbe1ce728266e683574f6552e087df214b1e34d Mon Sep 17 00:00:00 2001
From: Rose <gfunni234 at gmail.com>
Date: Sun, 27 Jul 2025 11:11:14 -0400
Subject: [PATCH 5/9] Remove +mve,+lob

---
 llvm/test/CodeGen/Thumb/scmp.ll | 2 +-
 llvm/test/CodeGen/Thumb/ucmp.ll | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/llvm/test/CodeGen/Thumb/scmp.ll b/llvm/test/CodeGen/Thumb/scmp.ll
index d74109347c369..41149571fab05 100644
--- a/llvm/test/CodeGen/Thumb/scmp.ll
+++ b/llvm/test/CodeGen/Thumb/scmp.ll
@@ -1,7 +1,7 @@
 ; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 5
 ; RUN: llc -mtriple=thumbv6m-eabi %s -o - | FileCheck %s -check-prefix=THUMB1
 ; RUN: llc -mtriple=thumbv7-apple-darwin %s -o - | FileCheck %s -check-prefix=THUMB2
-; RUN: llc -mtriple thumbv8.1m.main-none-eabi -mattr=+mve,+lob -o - %s | FileCheck %s --check-prefix=V81M
+; RUN: llc -mtriple thumbv8.1m.main-none-eabi -o - %s | FileCheck %s --check-prefix=V81M
 
 define i8 @scmp_8_8(i8 signext %x, i8 signext %y) nounwind {
 ; THUMB1-LABEL: scmp_8_8:
diff --git a/llvm/test/CodeGen/Thumb/ucmp.ll b/llvm/test/CodeGen/Thumb/ucmp.ll
index cce15afaeb3ab..5d0f57e2a9d72 100644
--- a/llvm/test/CodeGen/Thumb/ucmp.ll
+++ b/llvm/test/CodeGen/Thumb/ucmp.ll
@@ -1,7 +1,7 @@
 ; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 5
 ; RUN: llc -mtriple=thumbv6m-eabi %s -o - | FileCheck %s -check-prefix=THUMB1
 ; RUN: llc -mtriple=thumbv7-apple-darwin %s -o - | FileCheck %s -check-prefix=THUMB2
-; RUN: llc -mtriple thumbv8.1m.main-none-eabi -mattr=+mve,+lob -o - %s | FileCheck %s --check-prefix=V81M
+; RUN: llc -mtriple thumbv8.1m.main-none-eabi -o - %s | FileCheck %s --check-prefix=V81M
 
 define i8 @ucmp_8_8(i8 zeroext %x, i8 zeroext %y) nounwind {
 ; THUMB1-LABEL: ucmp_8_8:

>From 5dedea00478715f71bc130a6494857ceff7153c6 Mon Sep 17 00:00:00 2001
From: Rose <gfunni234 at gmail.com>
Date: Sun, 27 Jul 2025 17:13:59 -0400
Subject: [PATCH 6/9] Revert "Remove +mve,+lob"

This reverts commit 1cbe1ce728266e683574f6552e087df214b1e34d.
---
 llvm/test/CodeGen/Thumb/scmp.ll | 2 +-
 llvm/test/CodeGen/Thumb/ucmp.ll | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/llvm/test/CodeGen/Thumb/scmp.ll b/llvm/test/CodeGen/Thumb/scmp.ll
index 41149571fab05..d74109347c369 100644
--- a/llvm/test/CodeGen/Thumb/scmp.ll
+++ b/llvm/test/CodeGen/Thumb/scmp.ll
@@ -1,7 +1,7 @@
 ; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 5
 ; RUN: llc -mtriple=thumbv6m-eabi %s -o - | FileCheck %s -check-prefix=THUMB1
 ; RUN: llc -mtriple=thumbv7-apple-darwin %s -o - | FileCheck %s -check-prefix=THUMB2
-; RUN: llc -mtriple thumbv8.1m.main-none-eabi -o - %s | FileCheck %s --check-prefix=V81M
+; RUN: llc -mtriple thumbv8.1m.main-none-eabi -mattr=+mve,+lob -o - %s | FileCheck %s --check-prefix=V81M
 
 define i8 @scmp_8_8(i8 signext %x, i8 signext %y) nounwind {
 ; THUMB1-LABEL: scmp_8_8:
diff --git a/llvm/test/CodeGen/Thumb/ucmp.ll b/llvm/test/CodeGen/Thumb/ucmp.ll
index 5d0f57e2a9d72..cce15afaeb3ab 100644
--- a/llvm/test/CodeGen/Thumb/ucmp.ll
+++ b/llvm/test/CodeGen/Thumb/ucmp.ll
@@ -1,7 +1,7 @@
 ; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 5
 ; RUN: llc -mtriple=thumbv6m-eabi %s -o - | FileCheck %s -check-prefix=THUMB1
 ; RUN: llc -mtriple=thumbv7-apple-darwin %s -o - | FileCheck %s -check-prefix=THUMB2
-; RUN: llc -mtriple thumbv8.1m.main-none-eabi -o - %s | FileCheck %s --check-prefix=V81M
+; RUN: llc -mtriple thumbv8.1m.main-none-eabi -mattr=+mve,+lob -o - %s | FileCheck %s --check-prefix=V81M
 
 define i8 @ucmp_8_8(i8 zeroext %x, i8 zeroext %y) nounwind {
 ; THUMB1-LABEL: ucmp_8_8:

>From fdce6884d9ac953b4a46c677cec49da45b861859 Mon Sep 17 00:00:00 2001
From: AZero13 <gfunni234 at gmail.com>
Date: Tue, 29 Jul 2025 17:58:30 -0400
Subject: [PATCH 7/9] Use HasV8_1MMainlineOps

---
 llvm/lib/Target/ARM/ARMISelLowering.cpp | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/llvm/lib/Target/ARM/ARMISelLowering.cpp b/llvm/lib/Target/ARM/ARMISelLowering.cpp
index 1a1f25cc7a90c..e062234a10406 100644
--- a/llvm/lib/Target/ARM/ARMISelLowering.cpp
+++ b/llvm/lib/Target/ARM/ARMISelLowering.cpp
@@ -802,10 +802,10 @@ ARMTargetLowering::ARMTargetLowering(const TargetMachine &TM_,
     setOperationAction(ISD::BSWAP, VT, Expand);
   }
 
-  if (!Subtarget->isThumb1Only() && !Subtarget->hasMVEIntegerOps())
+  if (!Subtarget->isThumb1Only() && !Subtarget->hasV8_1MMainlineOps())
     setOperationAction(ISD::SCMP, MVT::i32, Custom);
 
-  if (!Subtarget->hasMVEIntegerOps())
+  if (!Subtarget->HasV8_1MMainlineOps())
     setOperationAction(ISD::UCMP, MVT::i32, Custom);
 
   setOperationAction(ISD::ConstantFP, MVT::f32, Custom);

>From 0c9a4582bf651fde74072d1c87e17eef09ece9fd Mon Sep 17 00:00:00 2001
From: AZero13 <gfunni234 at gmail.com>
Date: Tue, 29 Jul 2025 17:58:46 -0400
Subject: [PATCH 8/9] Update ARMISelLowering.cpp

---
 llvm/lib/Target/ARM/ARMISelLowering.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/llvm/lib/Target/ARM/ARMISelLowering.cpp b/llvm/lib/Target/ARM/ARMISelLowering.cpp
index e062234a10406..9b20cd8d14995 100644
--- a/llvm/lib/Target/ARM/ARMISelLowering.cpp
+++ b/llvm/lib/Target/ARM/ARMISelLowering.cpp
@@ -805,7 +805,7 @@ ARMTargetLowering::ARMTargetLowering(const TargetMachine &TM_,
   if (!Subtarget->isThumb1Only() && !Subtarget->hasV8_1MMainlineOps())
     setOperationAction(ISD::SCMP, MVT::i32, Custom);
 
-  if (!Subtarget->HasV8_1MMainlineOps())
+  if (!Subtarget->hasV8_1MMainlineOps())
     setOperationAction(ISD::UCMP, MVT::i32, Custom);
 
   setOperationAction(ISD::ConstantFP, MVT::f32, Custom);

>From 20ce9edb8721953a5269ccb8da6b5a5c1129ca3c Mon Sep 17 00:00:00 2001
From: AZero13 <gfunni234 at gmail.com>
Date: Mon, 4 Aug 2025 15:18:06 -0400
Subject: [PATCH 9/9] Fix issues

---
 llvm/lib/Target/ARM/ARMISelLowering.cpp | 134 +++++++++---------------
 llvm/lib/Target/ARM/ARMISelLowering.h   |   1 +
 llvm/test/CodeGen/Thumb/scmp.ll         |  55 +---------
 llvm/test/CodeGen/Thumb/ucmp.ll         |   2 +-
 4 files changed, 51 insertions(+), 141 deletions(-)

diff --git a/llvm/lib/Target/ARM/ARMISelLowering.cpp b/llvm/lib/Target/ARM/ARMISelLowering.cpp
index 9b20cd8d14995..784683edb22fc 100644
--- a/llvm/lib/Target/ARM/ARMISelLowering.cpp
+++ b/llvm/lib/Target/ARM/ARMISelLowering.cpp
@@ -1635,7 +1635,7 @@ bool ARMTargetLowering::useSoftFloat() const {
 }
 
 bool ARMTargetLowering::shouldExpandCmpUsingSelects(EVT VT) const {
-  return (!Subtarget->isThumb1Only() && VT.getSizeInBits() <= 32);
+  return !Subtarget->isThumb1Only() && VT.getSizeInBits() <= 32;
 }
 
 // FIXME: It might make sense to define the representative register class as the
@@ -10624,22 +10624,17 @@ SDValue ARMTargetLowering::LowerFP_TO_BF16(SDValue Op,
   return DAG.getBitcast(MVT::i32, Res);
 }
 
-SDValue ARMTargetLowering::LowerSCMP(SDValue Op, SelectionDAG &DAG) const {
+SDValue ARMTargetLowering::LowerCMP_COMMON(SDValue Op, SelectionDAG &DAG, 
+                                           ARMCC::CondCodes GTCond, ARMCC::CondCodes LTCond, 
+                                           bool IsSigned) const {
   SDLoc dl(Op);
   SDValue LHS = Op.getOperand(0);
   SDValue RHS = Op.getOperand(1);
 
-  // For the ARM assembly pattern:
-  // subs r0, r0, r1   ; subtract RHS from LHS and set flags
-  // movgt r0, #1      ; if LHS > RHS, set result to 1
-  // mvnlt r0, #0      ; if LHS < RHS, set result to -1 (mvn #0 = -1)
-  //                   ; if LHS == RHS, result remains 0 from the subs
-
   // Optimization: if RHS is a subtraction against 0, use ADDC instead of SUBC
   // Check if RHS is (0 - something), and if so use ADDC with LHS + something
-  SDValue SubResult, Flags;
-  bool CanUseAdd = false;
   SDValue AddOperand;
+  unsigned Opcode = ARMISD::SUBC;
 
   // Check if RHS is a subtraction against 0: (0 - X)
   if (RHS.getOpcode() == ISD::SUB) {
@@ -10648,44 +10643,54 @@ SDValue ARMTargetLowering::LowerSCMP(SDValue Op, SelectionDAG &DAG) const {
 
     // Check if it's 0 - X
     if (isNullConstant(SubLHS)) {
-      // For SCMP: only if X is known to never be INT_MIN (to avoid overflow)
-      if (RHS->getFlags().hasNoSignedWrap() || !DAG.computeKnownBits(SubRHS)
-                                                    .getSignedMinValue()
-                                                    .isMinSignedValue()) {
-        CanUseAdd = true;
-        AddOperand = SubRHS; // Replace RHS with X, so we do LHS + X instead of
-                             // LHS - (0 - X)
+      bool CanUseAdd = false;
+      if (IsSigned) {
+        // For SCMP: only if X is known to never be INT_MIN (to avoid overflow)
+        if (RHS->getFlags().hasNoSignedWrap() || !DAG.computeKnownBits(SubRHS)
+                                                      .getSignedMinValue()
+                                                      .isMinSignedValue()) {
+          CanUseAdd = true;
+        }
+      } else {
+        // For UCMP: only if X is known to never be zero
+        if (DAG.isKnownNeverZero(SubRHS)) {
+          CanUseAdd = true;
+        }
+      }
+
+      if (CanUseAdd) {
+        Opcode = ARMISD::ADDC;
+        AddOperand = SubRHS; // Replace RHS with X, so we do LHS + X instead of LHS - (0 - X)
       }
     }
   }
 
-  if (CanUseAdd) {
+  // Generate the operation with flags
+  SDValue OpWithFlags;
+  if (Opcode == ARMISD::ADDC) {
     // Use ADDC: LHS + AddOperand (where RHS was 0 - AddOperand)
-    SDValue AddWithFlags = DAG.getNode(
-        ARMISD::ADDC, dl, DAG.getVTList(MVT::i32, FlagsVT), LHS, AddOperand);
-    SubResult = AddWithFlags.getValue(0); // The addition result
-    Flags = AddWithFlags.getValue(1);     // The flags from ADDS
+    OpWithFlags = DAG.getNode(ARMISD::ADDC, dl, DAG.getVTList(MVT::i32, FlagsVT), LHS, AddOperand);
   } else {
     // Use ARMISD::SUBC to generate SUBS instruction (subtract with flags)
-    SDValue SubWithFlags = DAG.getNode(
-        ARMISD::SUBC, dl, DAG.getVTList(MVT::i32, FlagsVT), LHS, RHS);
-    SubResult = SubWithFlags.getValue(0); // The subtraction result
-    Flags = SubWithFlags.getValue(1);     // The flags from SUBS
+    OpWithFlags = DAG.getNode(ARMISD::SUBC, dl, DAG.getVTList(MVT::i32, FlagsVT), LHS, RHS);
   }
 
+  SDValue OpResult = OpWithFlags.getValue(0); // The operation result
+  SDValue Flags = OpWithFlags.getValue(1);    // The flags
+
   // Constants for conditional moves
   SDValue One = DAG.getConstant(1, dl, MVT::i32);
   SDValue MinusOne = DAG.getAllOnesConstant(dl, MVT::i32);
 
-  // movgt: if greater than, set to 1
-  SDValue GTCond = DAG.getConstant(ARMCC::GT, dl, MVT::i32);
+  // First conditional move: if greater than, set to 1
+  SDValue GTCondValue = DAG.getConstant(GTCond, dl, MVT::i32);
   SDValue Result1 =
-      DAG.getNode(ARMISD::CMOV, dl, MVT::i32, SubResult, One, GTCond, Flags);
+      DAG.getNode(ARMISD::CMOV, dl, MVT::i32, OpResult, One, GTCondValue, Flags);
 
-  // mvnlt: if less than, set to -1 (equivalent to mvn #0)
-  SDValue LTCond = DAG.getConstant(ARMCC::LT, dl, MVT::i32);
+  // Second conditional move: if less than, set to -1
+  SDValue LTCondValue = DAG.getConstant(LTCond, dl, MVT::i32);
   SDValue Result2 =
-      DAG.getNode(ARMISD::CMOV, dl, MVT::i32, Result1, MinusOne, LTCond, Flags);
+      DAG.getNode(ARMISD::CMOV, dl, MVT::i32, Result1, MinusOne, LTCondValue, Flags);
 
   if (Op.getValueType() != MVT::i32)
     Result2 = DAG.getSExtOrTrunc(Result2, dl, Op.getValueType());
@@ -10693,6 +10698,16 @@ SDValue ARMTargetLowering::LowerSCMP(SDValue Op, SelectionDAG &DAG) const {
   return Result2;
 }
 
+SDValue ARMTargetLowering::LowerSCMP(SDValue Op, SelectionDAG &DAG) const {
+  // For the ARM assembly pattern:
+  // subs r0, r0, r1   ; subtract RHS from LHS and set flags
+  // movgt r0, #1      ; if LHS > RHS, set result to 1
+  // mvnlt r0, #0      ; if LHS < RHS, set result to -1 (mvn #0 = -1)
+  //                   ; if LHS == RHS, result remains 0 from the subs
+
+  return LowerCMP_COMMON(Op, DAG, ARMCC::GT, ARMCC::LT, /*IsSigned=*/true);
+}
+
 SDValue ARMTargetLowering::LowerUCMP(SDValue Op, SelectionDAG &DAG) const {
   SDLoc dl(Op);
   SDValue LHS = Op.getOperand(0);
@@ -10743,60 +10758,7 @@ SDValue ARMTargetLowering::LowerUCMP(SDValue Op, SelectionDAG &DAG) const {
   // mvnlo r0, #0      ; if LHS < RHS (unsigned), set result to -1
   //                   ; if LHS == RHS, result remains 0 from the subs
 
-  // Optimization: if RHS is a subtraction against 0, use ADDC instead of SUBC
-  // Check if RHS is (0 - something), and if so use ADDC with LHS + something
-  SDValue SubResult, Flags;
-  bool CanUseAdd = false;
-  SDValue AddOperand;
-
-  // Check if RHS is a subtraction against 0: (0 - X)
-  if (RHS.getOpcode() == ISD::SUB) {
-    SDValue SubLHS = RHS.getOperand(0);
-    SDValue SubRHS = RHS.getOperand(1);
-
-    // Check if it's 0 - X
-    if (isNullConstant(SubLHS)) {
-      // For UCMP: only if X is known to never be zero
-      if (DAG.isKnownNeverZero(SubRHS)) {
-        CanUseAdd = true;
-        AddOperand = SubRHS; // Replace RHS with X, so we do LHS + X instead of
-                             // LHS - (0 - X)
-      }
-    }
-  }
-
-  if (CanUseAdd) {
-    // Use ADDC: LHS + AddOperand (where RHS was 0 - AddOperand)
-    SDValue AddWithFlags = DAG.getNode(
-        ARMISD::ADDC, dl, DAG.getVTList(MVT::i32, FlagsVT), LHS, AddOperand);
-    SubResult = AddWithFlags.getValue(0); // The addition result
-    Flags = AddWithFlags.getValue(1);     // The flags from ADDS
-  } else {
-    // Use ARMISD::SUBC to generate SUBS instruction (subtract with flags)
-    SDValue SubWithFlags = DAG.getNode(
-        ARMISD::SUBC, dl, DAG.getVTList(MVT::i32, FlagsVT), LHS, RHS);
-    SubResult = SubWithFlags.getValue(0); // The subtraction result
-    Flags = SubWithFlags.getValue(1);     // The flags from SUBS
-  }
-
-  // Constants for conditional moves
-  SDValue One = DAG.getConstant(1, dl, MVT::i32);
-  SDValue MinusOne = DAG.getAllOnesConstant(dl, MVT::i32);
-
-  // movhi: if higher (unsigned greater than), set to 1
-  SDValue HICond = DAG.getConstant(ARMCC::HI, dl, MVT::i32);
-  SDValue Result1 =
-      DAG.getNode(ARMISD::CMOV, dl, MVT::i32, SubResult, One, HICond, Flags);
-
-  // mvnlo: if lower (unsigned less than), set to -1
-  SDValue LOCond = DAG.getConstant(ARMCC::LO, dl, MVT::i32);
-  SDValue Result2 =
-      DAG.getNode(ARMISD::CMOV, dl, MVT::i32, Result1, MinusOne, LOCond, Flags);
-
-  if (Op.getValueType() != MVT::i32)
-    Result2 = DAG.getSExtOrTrunc(Result2, dl, Op.getValueType());
-
-  return Result2;
+  return LowerCMP_COMMON(Op, DAG, ARMCC::HI, ARMCC::LO, /*IsSigned=*/false);
 }
 
 SDValue ARMTargetLowering::LowerOperation(SDValue Op, SelectionDAG &DAG) const {
diff --git a/llvm/lib/Target/ARM/ARMISelLowering.h b/llvm/lib/Target/ARM/ARMISelLowering.h
index f3b132da7b946..65201c502f19f 100644
--- a/llvm/lib/Target/ARM/ARMISelLowering.h
+++ b/llvm/lib/Target/ARM/ARMISelLowering.h
@@ -907,6 +907,7 @@ class VectorType;
     SDValue LowerFP_TO_BF16(SDValue Op, SelectionDAG &DAG) const;
     SDValue LowerSCMP(SDValue Op, SelectionDAG &DAG) const;
     SDValue LowerUCMP(SDValue Op, SelectionDAG &DAG) const;
+    SDValue LowerCMP_COMMON(SDValue Op, SelectionDAG &DAG, ARMCC::CondCodes GTCond, ARMCC::CondCodes LTCond, bool IsSigned) const;
 
     Register getRegisterByName(const char* RegName, LLT VT,
                                const MachineFunction &MF) const override;
diff --git a/llvm/test/CodeGen/Thumb/scmp.ll b/llvm/test/CodeGen/Thumb/scmp.ll
index d74109347c369..c0024492b3a6d 100644
--- a/llvm/test/CodeGen/Thumb/scmp.ll
+++ b/llvm/test/CodeGen/Thumb/scmp.ll
@@ -1,7 +1,7 @@
 ; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 5
 ; RUN: llc -mtriple=thumbv6m-eabi %s -o - | FileCheck %s -check-prefix=THUMB1
 ; RUN: llc -mtriple=thumbv7-apple-darwin %s -o - | FileCheck %s -check-prefix=THUMB2
-; RUN: llc -mtriple thumbv8.1m.main-none-eabi -mattr=+mve,+lob -o - %s | FileCheck %s --check-prefix=V81M
+; RUN: llc -mtriple thumbv8.1m.main-none-eabi -o - %s | FileCheck %s --check-prefix=V81M
 
 define i8 @scmp_8_8(i8 signext %x, i8 signext %y) nounwind {
 ; THUMB1-LABEL: scmp_8_8:
@@ -127,8 +127,6 @@ define i8 @scmp_8_32(i32 %x, i32 %y) nounwind {
 }
 
 define i8 @scmp_8_64(i64 %x, i64 %y) nounwind {
-; CHECK-LABEL: scmp_8_64:
-; CHECK:       @ %bb.0:
 ; THUMB1-LABEL: scmp_8_64:
 ; THUMB1:       @ %bb.0:
 ; THUMB1-NEXT:    .save {r4, r5, r6, lr}
@@ -182,28 +180,6 @@ define i8 @scmp_8_64(i64 %x, i64 %y) nounwind {
 }
 
 define i8 @scmp_8_128(i128 %x, i128 %y) nounwind {
-; CHECK-LABEL: scmp_8_128:
-; CHECK:       @ %bb.0:
-; CHECK-NEXT:    push {r4, r5, r6, lr}
-; CHECK-NEXT:    add.w lr, sp, #16
-; CHECK-NEXT:    ldr r4, [sp, #28]
-; CHECK-NEXT:    movs r5, #0
-; CHECK-NEXT:    ldm.w lr, {r9, r12, lr}
-; CHECK-NEXT:    subs.w r6, r0, r9
-; CHECK-NEXT:    sbcs.w r6, r1, r12
-; CHECK-NEXT:    sbcs.w r6, r2, lr
-; CHECK-NEXT:    sbcs.w r6, r3, r4
-; CHECK-NEXT:    mov.w r6, #0
-; CHECK-NEXT:    it lt
-; CHECK-NEXT:    movlt r6, #1
-; CHECK-NEXT:    subs.w r0, r9, r0
-; CHECK-NEXT:    sbcs.w r0, r12, r1
-; CHECK-NEXT:    sbcs.w r0, lr, r2
-; CHECK-NEXT:    sbcs.w r0, r4, r3
-; CHECK-NEXT:    it lt
-; CHECK-NEXT:    movlt r5, #1
-; CHECK-NEXT:    subs r0, r5, r6
-; CHECK-NEXT:    pop {r4, r5, r6, pc}
 ; THUMB1-LABEL: scmp_8_128:
 ; THUMB1:       @ %bb.0:
 ; THUMB1-NEXT:    .save {r4, r5, r6, r7, lr}
@@ -335,20 +311,6 @@ define i32 @scmp_32_32(i32 %x, i32 %y) nounwind {
 }
 
 define i32 @scmp_32_64(i64 %x, i64 %y) nounwind {
-; CHECK-LABEL: scmp_32_64:
-; CHECK:       @ %bb.0:
-; CHECK-NEXT:    subs.w r12, r0, r2
-; CHECK-NEXT:    mov.w r9, #0
-; CHECK-NEXT:    sbcs.w r12, r1, r3
-; CHECK-NEXT:    mov.w r12, #0
-; CHECK-NEXT:    it lt
-; CHECK-NEXT:    movlt.w r12, #1
-; CHECK-NEXT:    subs r0, r2, r0
-; CHECK-NEXT:    sbcs.w r0, r3, r1
-; CHECK-NEXT:    it lt
-; CHECK-NEXT:    movlt.w r9, #1
-; CHECK-NEXT:    sub.w r0, r9, r12
-; CHECK-NEXT:    bx lr
 ; THUMB1-LABEL: scmp_32_64:
 ; THUMB1:       @ %bb.0:
 ; THUMB1-NEXT:    .save {r4, r5, r6, lr}
@@ -402,21 +364,6 @@ define i32 @scmp_32_64(i64 %x, i64 %y) nounwind {
 }
 
 define i64 @scmp_64_64(i64 %x, i64 %y) nounwind {
-; CHECK-LABEL: scmp_64_64:
-; CHECK:       @ %bb.0:
-; CHECK-NEXT:    subs.w r12, r0, r2
-; CHECK-NEXT:    mov.w r9, #0
-; CHECK-NEXT:    sbcs.w r12, r1, r3
-; CHECK-NEXT:    mov.w r12, #0
-; CHECK-NEXT:    it lt
-; CHECK-NEXT:    movlt.w r12, #1
-; CHECK-NEXT:    subs r0, r2, r0
-; CHECK-NEXT:    sbcs.w r0, r3, r1
-; CHECK-NEXT:    it lt
-; CHECK-NEXT:    movlt.w r9, #1
-; CHECK-NEXT:    sub.w r0, r9, r12
-; CHECK-NEXT:    asrs r1, r0, #31
-; CHECK-NEXT:    bx lr
 ; THUMB1-LABEL: scmp_64_64:
 ; THUMB1:       @ %bb.0:
 ; THUMB1-NEXT:    .save {r4, r5, r6, lr}
diff --git a/llvm/test/CodeGen/Thumb/ucmp.ll b/llvm/test/CodeGen/Thumb/ucmp.ll
index cce15afaeb3ab..5d0f57e2a9d72 100644
--- a/llvm/test/CodeGen/Thumb/ucmp.ll
+++ b/llvm/test/CodeGen/Thumb/ucmp.ll
@@ -1,7 +1,7 @@
 ; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 5
 ; RUN: llc -mtriple=thumbv6m-eabi %s -o - | FileCheck %s -check-prefix=THUMB1
 ; RUN: llc -mtriple=thumbv7-apple-darwin %s -o - | FileCheck %s -check-prefix=THUMB2
-; RUN: llc -mtriple thumbv8.1m.main-none-eabi -mattr=+mve,+lob -o - %s | FileCheck %s --check-prefix=V81M
+; RUN: llc -mtriple thumbv8.1m.main-none-eabi -o - %s | FileCheck %s --check-prefix=V81M
 
 define i8 @ucmp_8_8(i8 zeroext %x, i8 zeroext %y) nounwind {
 ; THUMB1-LABEL: ucmp_8_8:



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