[llvm] [AArch64] Transform add(x, abs(y)) -> saba(x, y, 0) (PR #156615)

via llvm-commits llvm-commits at lists.llvm.org
Wed Sep 3 09:03:14 PDT 2025


llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-backend-aarch64

Author: Hari Limaye (hazzlim)

<details>
<summary>Changes</summary>

Add a DAGCombine to perform the following transformations: 
- add(x, abs(y)) -> saba(x, y, 0)
- add(x, zext(abs(y))) -> sabal(x, y, 0)

As well as being a useful generic transformation, this also fixes an issue where LLVM de-optimises [US]ABA neon ACLE intrinsics into separate ABD+ADD instructions when one of the operands is a zero vector.


---
Full diff: https://github.com/llvm/llvm-project/pull/156615.diff


3 Files Affected:

- (modified) llvm/lib/Target/AArch64/AArch64ISelLowering.cpp (+54) 
- (modified) llvm/lib/Target/AArch64/AArch64InstrInfo.td (+25) 
- (modified) llvm/test/CodeGen/AArch64/neon-saba.ll (+262) 


``````````diff
diff --git a/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp b/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
index f1e8fb7f77652..b22cd04a6f3c0 100644
--- a/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
+++ b/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
@@ -50,6 +50,7 @@
 #include "llvm/CodeGen/MachineInstrBuilder.h"
 #include "llvm/CodeGen/MachineMemOperand.h"
 #include "llvm/CodeGen/MachineRegisterInfo.h"
+#include "llvm/CodeGen/SDPatternMatch.h"
 #include "llvm/CodeGen/SelectionDAG.h"
 #include "llvm/CodeGen/SelectionDAGNodes.h"
 #include "llvm/CodeGen/TargetCallingConv.h"
@@ -21913,6 +21914,56 @@ static SDValue performExtBinopLoadFold(SDNode *N, SelectionDAG &DAG) {
   return DAG.getNode(N->getOpcode(), DL, VT, Ext0, NShift);
 }
 
+// Transform the following:
+// - add(x, abs(y)) -> saba(x, y, 0)
+// - add(x, zext(abs(y))) -> sabal(x, y, 0)
+static SDValue performAddSABACombine(SDNode *N,
+                                     TargetLowering::DAGCombinerInfo &DCI) {
+  if (N->getOpcode() != ISD::ADD)
+    return SDValue();
+
+  EVT VT = N->getValueType(0);
+  if (!VT.isFixedLengthVector())
+    return SDValue();
+
+  SDValue N0 = N->getOperand(0);
+  SDValue N1 = N->getOperand(1);
+
+  auto MatchAbsOrZExtAbs = [](SDValue V0, SDValue V1, SDValue &AbsOp,
+                              SDValue &Other, bool &IsZExt) {
+    Other = V1;
+    if (sd_match(V0, m_Abs(SDPatternMatch::m_Value(AbsOp)))) {
+      IsZExt = false;
+      return true;
+    }
+    if (sd_match(V0, SDPatternMatch::m_ZExt(
+                         m_Abs(SDPatternMatch::m_Value(AbsOp))))) {
+      IsZExt = true;
+      return true;
+    }
+
+    return false;
+  };
+
+  SDValue AbsOp;
+  SDValue Other;
+  bool IsZExt;
+  if (!MatchAbsOrZExtAbs(N0, N1, AbsOp, Other, IsZExt) &&
+      !MatchAbsOrZExtAbs(N1, N0, AbsOp, Other, IsZExt))
+    return SDValue();
+
+  // Don't perform this on abs(sub), as this will become an ABD/ABA anyway.
+  if (AbsOp.getOpcode() == ISD::SUB)
+    return SDValue();
+
+  SDLoc DL(N);
+  SDValue Zero = DCI.DAG.getConstant(0, DL, MVT::i64);
+  SDValue Zeros = DCI.DAG.getSplatVector(AbsOp.getValueType(), DL, Zero);
+
+  unsigned Opcode = IsZExt ? AArch64ISD::SABAL : AArch64ISD::SABA;
+  return DCI.DAG.getNode(Opcode, DL, VT, Other, AbsOp, Zeros);
+}
+
 static SDValue performAddSubCombine(SDNode *N,
                                     TargetLowering::DAGCombinerInfo &DCI) {
   // Try to change sum of two reductions.
@@ -21938,6 +21989,9 @@ static SDValue performAddSubCombine(SDNode *N,
   if (SDValue Val = performExtBinopLoadFold(N, DCI.DAG))
     return Val;
 
+  if (SDValue Val = performAddSABACombine(N, DCI))
+    return Val;
+
   return performAddSubLongCombine(N, DCI);
 }
 
diff --git a/llvm/lib/Target/AArch64/AArch64InstrInfo.td b/llvm/lib/Target/AArch64/AArch64InstrInfo.td
index 62b26b5239365..fdfde5ea1dc37 100644
--- a/llvm/lib/Target/AArch64/AArch64InstrInfo.td
+++ b/llvm/lib/Target/AArch64/AArch64InstrInfo.td
@@ -1059,6 +1059,10 @@ def AArch64sdot     : SDNode<"AArch64ISD::SDOT", SDT_AArch64Dot>;
 def AArch64udot     : SDNode<"AArch64ISD::UDOT", SDT_AArch64Dot>;
 def AArch64usdot    : SDNode<"AArch64ISD::USDOT", SDT_AArch64Dot>;
 
+// saba/sabal
+def AArch64neonsaba     : SDNode<"AArch64ISD::SABA", SDT_AArch64trivec>;
+def AArch64neonsabal    : SDNode<"AArch64ISD::SABAL", SDT_AArch64Dot>;
+
 // Vector across-lanes addition
 // Only the lower result lane is defined.
 def AArch64saddv    : SDNode<"AArch64ISD::SADDV", SDT_AArch64UnaryVec>;
@@ -6121,6 +6125,19 @@ defm SQRDMLAH : SIMDThreeSameVectorSQRDMLxHTiedHS<1,0b10000,"sqrdmlah",
 defm SQRDMLSH : SIMDThreeSameVectorSQRDMLxHTiedHS<1,0b10001,"sqrdmlsh",
                                                     int_aarch64_neon_sqrdmlsh>;
 
+def : Pat<(AArch64neonsaba (v8i8 V64:$Rd), V64:$Rn, V64:$Rm),
+          (SABAv8i8 V64:$Rd, V64:$Rn, V64:$Rm)>;
+def : Pat<(AArch64neonsaba (v4i16 V64:$Rd), V64:$Rn, V64:$Rm),
+          (SABAv4i16 V64:$Rd, V64:$Rn, V64:$Rm)>;
+def : Pat<(AArch64neonsaba (v2i32 V64:$Rd), V64:$Rn, V64:$Rm),
+          (SABAv2i32 V64:$Rd, V64:$Rn, V64:$Rm)>;
+def : Pat<(AArch64neonsaba (v16i8 V128:$Rd), V128:$Rn, V128:$Rm),
+          (SABAv16i8 V128:$Rd, V128:$Rn, V128:$Rm)>;
+def : Pat<(AArch64neonsaba (v8i16 V128:$Rd), V128:$Rn, V128:$Rm),
+          (SABAv8i16 V128:$Rd, V128:$Rn, V128:$Rm)>;
+def : Pat<(AArch64neonsaba (v4i32 V128:$Rd), V128:$Rn, V128:$Rm),
+          (SABAv4i32 V128:$Rd, V128:$Rn, V128:$Rm)>;
+
 defm AND : SIMDLogicalThreeVector<0, 0b00, "and", and>;
 defm BIC : SIMDLogicalThreeVector<0, 0b01, "bic",
                                   BinOpFrag<(and node:$LHS, (vnot node:$RHS))> >;
@@ -7008,6 +7025,14 @@ defm : AddSubHNPatterns<ADDHNv2i64_v2i32, ADDHNv2i64_v4i32,
                         SUBHNv2i64_v2i32, SUBHNv2i64_v4i32,
                         v2i32, v2i64, 32>;
 
+// Patterns for SABAL
+def : Pat<(AArch64neonsabal (v8i16 V128:$Rd), (v8i8 V64:$Rn), (v8i8 V64:$Rm)),
+          (SABALv8i8_v8i16 V128:$Rd, V64:$Rn, V64:$Rm)>;
+def : Pat<(AArch64neonsabal (v4i32 V128:$Rd), (v4i16 V64:$Rn), (v4i16 V64:$Rm)),
+          (SABALv4i16_v4i32 V128:$Rd, V64:$Rn, V64:$Rm)>;
+def : Pat<(AArch64neonsabal (v2i64 V128:$Rd), (v2i32 V64:$Rn), (v2i32 V64:$Rm)),
+          (SABALv2i32_v2i64 V128:$Rd, V64:$Rn, V64:$Rm)>;
+
 //----------------------------------------------------------------------------
 // AdvSIMD bitwise extract from vector instruction.
 //----------------------------------------------------------------------------
diff --git a/llvm/test/CodeGen/AArch64/neon-saba.ll b/llvm/test/CodeGen/AArch64/neon-saba.ll
index 19967bd1a69ec..c8de6b21e9764 100644
--- a/llvm/test/CodeGen/AArch64/neon-saba.ll
+++ b/llvm/test/CodeGen/AArch64/neon-saba.ll
@@ -174,6 +174,268 @@ define <8 x i8> @saba_sabd_8b(<8 x i8> %a, <8 x i8> %b, <8 x i8> %c) #0 {
   ret <8 x i8> %add
 }
 
+; SABA from ADD(SABD(X, ZEROS))
+
+define <4 x i32> @saba_sabd_zeros_4s(<4 x i32> %a, <4 x i32> %b) #0 {
+; CHECK-LABEL: saba_sabd_zeros_4s:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    movi v2.2d, #0000000000000000
+; CHECK-NEXT:    saba v0.4s, v1.4s, v2.4s
+; CHECK-NEXT:    ret
+  %sabd = call <4 x i32> @llvm.aarch64.neon.sabd.v4i32(<4 x i32> %b, <4 x i32> zeroinitializer)
+  %add = add <4 x i32> %sabd, %a
+  ret <4 x i32> %add
+}
+
+define <2 x i32> @saba_sabd_zeros_2s(<2 x i32> %a, <2 x i32> %b) #0 {
+; CHECK-LABEL: saba_sabd_zeros_2s:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    movi v2.2d, #0000000000000000
+; CHECK-NEXT:    saba v0.2s, v1.2s, v2.2s
+; CHECK-NEXT:    ret
+  %sabd = call <2 x i32> @llvm.aarch64.neon.sabd.v2i32(<2 x i32> %b, <2 x i32> zeroinitializer)
+  %add = add <2 x i32> %sabd, %a
+  ret <2 x i32> %add
+}
+
+define <8 x i16> @saba_sabd_zeros_8h(<8 x i16> %a, <8 x i16> %b) #0 {
+; CHECK-LABEL: saba_sabd_zeros_8h:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    movi v2.2d, #0000000000000000
+; CHECK-NEXT:    saba v0.8h, v1.8h, v2.8h
+; CHECK-NEXT:    ret
+  %sabd = call <8 x i16> @llvm.aarch64.neon.sabd.v8i16(<8 x i16> %b, <8 x i16> zeroinitializer)
+  %add = add <8 x i16> %sabd, %a
+  ret <8 x i16> %add
+}
+
+define <4 x i16> @saba_sabd_zeros_4h(<4 x i16> %a, <4 x i16> %b) #0 {
+; CHECK-LABEL: saba_sabd_zeros_4h:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    movi v2.2d, #0000000000000000
+; CHECK-NEXT:    saba v0.4h, v1.4h, v2.4h
+; CHECK-NEXT:    ret
+  %sabd = call <4 x i16> @llvm.aarch64.neon.sabd.v4i16(<4 x i16> %b, <4 x i16> zeroinitializer)
+  %add = add <4 x i16> %sabd, %a
+  ret <4 x i16> %add
+}
+
+define <16 x i8> @saba_sabd_zeros_16b(<16 x i8> %a, <16 x i8> %b) #0 {
+; CHECK-LABEL: saba_sabd_zeros_16b:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    movi v2.2d, #0000000000000000
+; CHECK-NEXT:    saba v0.16b, v1.16b, v2.16b
+; CHECK-NEXT:    ret
+  %sabd = call <16 x i8> @llvm.aarch64.neon.sabd.v16i8(<16 x i8> %b, <16 x i8> zeroinitializer)
+  %add = add <16 x i8> %sabd, %a
+  ret <16 x i8> %add
+}
+
+define <8 x i8> @saba_sabd_zeros_8b(<8 x i8> %a, <8 x i8> %b) #0 {
+; CHECK-LABEL: saba_sabd_zeros_8b:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    movi v2.2d, #0000000000000000
+; CHECK-NEXT:    saba v0.8b, v1.8b, v2.8b
+; CHECK-NEXT:    ret
+  %sabd = call <8 x i8> @llvm.aarch64.neon.sabd.v8i8(<8 x i8> %b, <8 x i8> zeroinitializer)
+  %add = add <8 x i8> %sabd, %a
+  ret <8 x i8> %add
+}
+
+define <4 x i32> @saba_abs_zeros_4s(<4 x i32> %a, <4 x i32> %b) #0 {
+; CHECK-SD-LABEL: saba_abs_zeros_4s:
+; CHECK-SD:       // %bb.0:
+; CHECK-SD-NEXT:    movi v2.2d, #0000000000000000
+; CHECK-SD-NEXT:    saba v0.4s, v1.4s, v2.4s
+; CHECK-SD-NEXT:    ret
+;
+; CHECK-GI-LABEL: saba_abs_zeros_4s:
+; CHECK-GI:       // %bb.0:
+; CHECK-GI-NEXT:    abs v1.4s, v1.4s
+; CHECK-GI-NEXT:    add v0.4s, v0.4s, v1.4s
+; CHECK-GI-NEXT:    ret
+  %abs = call <4 x i32> @llvm.abs.v4i32(<4 x i32> %b, i1 true)
+  %add = add <4 x i32> %a, %abs
+  ret <4 x i32> %add
+}
+
+define <2 x i32> @saba_abs_zeros_2s(<2 x i32> %a, <2 x i32> %b) #0 {
+; CHECK-SD-LABEL: saba_abs_zeros_2s:
+; CHECK-SD:       // %bb.0:
+; CHECK-SD-NEXT:    movi v2.2d, #0000000000000000
+; CHECK-SD-NEXT:    saba v0.2s, v1.2s, v2.2s
+; CHECK-SD-NEXT:    ret
+;
+; CHECK-GI-LABEL: saba_abs_zeros_2s:
+; CHECK-GI:       // %bb.0:
+; CHECK-GI-NEXT:    abs v1.2s, v1.2s
+; CHECK-GI-NEXT:    add v0.2s, v0.2s, v1.2s
+; CHECK-GI-NEXT:    ret
+  %abs = call <2 x i32> @llvm.abs.v2i32(<2 x i32> %b, i1 true)
+  %add = add <2 x i32> %a, %abs
+  ret <2 x i32> %add
+}
+
+define <8 x i16> @saba_abs_zeros_8h(<8 x i16> %a, <8 x i16> %b) #0 {
+; CHECK-SD-LABEL: saba_abs_zeros_8h:
+; CHECK-SD:       // %bb.0:
+; CHECK-SD-NEXT:    movi v2.2d, #0000000000000000
+; CHECK-SD-NEXT:    saba v0.8h, v1.8h, v2.8h
+; CHECK-SD-NEXT:    ret
+;
+; CHECK-GI-LABEL: saba_abs_zeros_8h:
+; CHECK-GI:       // %bb.0:
+; CHECK-GI-NEXT:    abs v1.8h, v1.8h
+; CHECK-GI-NEXT:    add v0.8h, v0.8h, v1.8h
+; CHECK-GI-NEXT:    ret
+  %abs = call <8 x i16> @llvm.abs.v8i16(<8 x i16> %b, i1 true)
+  %add = add <8 x i16> %a, %abs
+  ret <8 x i16> %add
+}
+
+define <4 x i16> @saba_abs_zeros_4h(<4 x i16> %a, <4 x i16> %b) #0 {
+; CHECK-SD-LABEL: saba_abs_zeros_4h:
+; CHECK-SD:       // %bb.0:
+; CHECK-SD-NEXT:    movi v2.2d, #0000000000000000
+; CHECK-SD-NEXT:    saba v0.4h, v1.4h, v2.4h
+; CHECK-SD-NEXT:    ret
+;
+; CHECK-GI-LABEL: saba_abs_zeros_4h:
+; CHECK-GI:       // %bb.0:
+; CHECK-GI-NEXT:    abs v1.4h, v1.4h
+; CHECK-GI-NEXT:    add v0.4h, v0.4h, v1.4h
+; CHECK-GI-NEXT:    ret
+  %abs = call <4 x i16> @llvm.abs.v4i16(<4 x i16> %b, i1 true)
+  %add = add <4 x i16> %a, %abs
+  ret <4 x i16> %add
+}
+
+define <16 x i8> @saba_abs_zeros_16b(<16 x i8> %a, <16 x i8> %b) #0 {
+; CHECK-SD-LABEL: saba_abs_zeros_16b:
+; CHECK-SD:       // %bb.0:
+; CHECK-SD-NEXT:    movi v2.2d, #0000000000000000
+; CHECK-SD-NEXT:    saba v0.16b, v1.16b, v2.16b
+; CHECK-SD-NEXT:    ret
+;
+; CHECK-GI-LABEL: saba_abs_zeros_16b:
+; CHECK-GI:       // %bb.0:
+; CHECK-GI-NEXT:    abs v1.16b, v1.16b
+; CHECK-GI-NEXT:    add v0.16b, v0.16b, v1.16b
+; CHECK-GI-NEXT:    ret
+  %abs = call <16 x i8> @llvm.abs.v16i8(<16 x i8> %b, i1 true)
+  %add = add <16 x i8> %a, %abs
+  ret <16 x i8> %add
+}
+
+define <8 x i8> @saba_abs_zeros_8b(<8 x i8> %a, <8 x i8> %b) #0 {
+; CHECK-SD-LABEL: saba_abs_zeros_8b:
+; CHECK-SD:       // %bb.0:
+; CHECK-SD-NEXT:    movi v2.2d, #0000000000000000
+; CHECK-SD-NEXT:    saba v0.8b, v1.8b, v2.8b
+; CHECK-SD-NEXT:    ret
+;
+; CHECK-GI-LABEL: saba_abs_zeros_8b:
+; CHECK-GI:       // %bb.0:
+; CHECK-GI-NEXT:    abs v1.8b, v1.8b
+; CHECK-GI-NEXT:    add v0.8b, v0.8b, v1.8b
+; CHECK-GI-NEXT:    ret
+  %abs = call <8 x i8> @llvm.abs.v8i8(<8 x i8> %b, i1 true)
+  %add = add <8 x i8> %a, %abs
+  ret <8 x i8> %add
+}
+
+; SABAL from ADD(ZEXT(SABD(X, ZEROS)))
+
+define <2 x i64> @sabal_sabd_zeros_2s(<2 x i64> %a, <2 x i32> %b) #0 {
+; CHECK-LABEL: sabal_sabd_zeros_2s:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    movi v2.2d, #0000000000000000
+; CHECK-NEXT:    sabal v0.2d, v1.2s, v2.2s
+; CHECK-NEXT:    ret
+  %sabd = call <2 x i32> @llvm.aarch64.neon.sabd.v2i32(<2 x i32> %b, <2 x i32> zeroinitializer)
+  %sabd.zext = zext <2 x i32> %sabd to <2 x i64>
+  %add = add <2 x i64> %a, %sabd.zext
+  ret <2 x i64> %add
+}
+
+define <4 x i32> @sabal_sabd_zeros_4h(<4 x i32> %a, <4 x i16> %b) #0 {
+; CHECK-LABEL: sabal_sabd_zeros_4h:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    movi v2.2d, #0000000000000000
+; CHECK-NEXT:    sabal v0.4s, v1.4h, v2.4h
+; CHECK-NEXT:    ret
+  %sabd = call <4 x i16> @llvm.aarch64.neon.sabd.v4i16(<4 x i16> %b, <4 x i16> zeroinitializer)
+  %sabd.zext = zext <4 x i16> %sabd to <4 x i32>
+  %add = add <4 x i32> %a, %sabd.zext
+  ret <4 x i32> %add
+}
+
+define <8 x i16> @sabal_sabd_zeros_8b(<8 x i16> %a, <8 x i8> %b) #0 {
+; CHECK-LABEL: sabal_sabd_zeros_8b:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    movi v2.2d, #0000000000000000
+; CHECK-NEXT:    sabal v0.8h, v1.8b, v2.8b
+; CHECK-NEXT:    ret
+  %sabd = call <8 x i8> @llvm.aarch64.neon.sabd.v8i8(<8 x i8> %b, <8 x i8> zeroinitializer)
+  %sabd.zext = zext <8 x i8> %sabd to <8 x i16>
+  %add = add <8 x i16> %a, %sabd.zext
+  ret <8 x i16> %add
+}
+
+define <2 x i64> @sabal_abs_zeros_2s(<2 x i64> %a, <2 x i32> %b) #0 {
+; CHECK-SD-LABEL: sabal_abs_zeros_2s:
+; CHECK-SD:       // %bb.0:
+; CHECK-SD-NEXT:    movi v2.2d, #0000000000000000
+; CHECK-SD-NEXT:    sabal v0.2d, v1.2s, v2.2s
+; CHECK-SD-NEXT:    ret
+;
+; CHECK-GI-LABEL: sabal_abs_zeros_2s:
+; CHECK-GI:       // %bb.0:
+; CHECK-GI-NEXT:    abs v1.2s, v1.2s
+; CHECK-GI-NEXT:    uaddw v0.2d, v0.2d, v1.2s
+; CHECK-GI-NEXT:    ret
+  %abs = call <2 x i32> @llvm.abs.v2i32(<2 x i32> %b, i1 true)
+  %abs.zext = zext <2 x i32> %abs to <2 x i64>
+  %add = add <2 x i64> %a, %abs.zext
+  ret <2 x i64> %add
+}
+
+define <4 x i32> @sabal_abs_zeros_4h(<4 x i32> %a, <4 x i16> %b) #0 {
+; CHECK-SD-LABEL: sabal_abs_zeros_4h:
+; CHECK-SD:       // %bb.0:
+; CHECK-SD-NEXT:    movi v2.2d, #0000000000000000
+; CHECK-SD-NEXT:    sabal v0.4s, v1.4h, v2.4h
+; CHECK-SD-NEXT:    ret
+;
+; CHECK-GI-LABEL: sabal_abs_zeros_4h:
+; CHECK-GI:       // %bb.0:
+; CHECK-GI-NEXT:    abs v1.4h, v1.4h
+; CHECK-GI-NEXT:    uaddw v0.4s, v0.4s, v1.4h
+; CHECK-GI-NEXT:    ret
+  %abs = call <4 x i16> @llvm.abs.v4i16(<4 x i16> %b, i1 true)
+  %abs.zext = zext <4 x i16> %abs to <4 x i32>
+  %add = add <4 x i32> %a, %abs.zext
+  ret <4 x i32> %add
+}
+
+define <8 x i16> @sabal_abs_zeros_8b(<8 x i16> %a, <8 x i8> %b) #0 {
+; CHECK-SD-LABEL: sabal_abs_zeros_8b:
+; CHECK-SD:       // %bb.0:
+; CHECK-SD-NEXT:    movi v2.2d, #0000000000000000
+; CHECK-SD-NEXT:    sabal v0.8h, v1.8b, v2.8b
+; CHECK-SD-NEXT:    ret
+;
+; CHECK-GI-LABEL: sabal_abs_zeros_8b:
+; CHECK-GI:       // %bb.0:
+; CHECK-GI-NEXT:    abs v1.8b, v1.8b
+; CHECK-GI-NEXT:    uaddw v0.8h, v0.8h, v1.8b
+; CHECK-GI-NEXT:    ret
+  %abs = call <8 x i8> @llvm.abs.v8i8(<8 x i8> %b, i1 true)
+  %abs.zext = zext <8 x i8> %abs to <8 x i16>
+  %add = add <8 x i16> %a, %abs.zext
+  ret <8 x i16> %add
+}
+
 declare <4 x i32> @llvm.abs.v4i32(<4 x i32>, i1)
 declare <2 x i32> @llvm.abs.v2i32(<2 x i32>, i1)
 declare <8 x i16> @llvm.abs.v8i16(<8 x i16>, i1)

``````````

</details>


https://github.com/llvm/llvm-project/pull/156615


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