[llvm] [GlobalISel][AArch64] Add support for sli/sri intrinsics (PR #173364)

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Tue Dec 23 06:19:44 PST 2025


llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-backend-aarch64

Author: Joshua Rodriguez (JoshdRod)

<details>
<summary>Changes</summary>

GISel previously failed to lower the sli and sri family of intrinsics. This patch fixes this.

- sli/sri intrinsics are now lowered to G_SLI / G_SRI GlobalISel nodes during Legalisation.
MIRBuilder is used over LowerTriOp to build the instruction here, as LowerTriOp treats all operands as registers, whilst the last operand of sli/sri is an immediate value.

- Intrinsics are treated as "always defines fp" and "always uses fp", to ensure vectors are always placed on floating point registers.
This fixes an issue where 1-element vectors are placed on general purpose registers, as IR Translation converts these vectors to i64s.

This PR is a replica of #<!-- -->171448, which was incorrectly merged into the wrong branch.

---
Full diff: https://github.com/llvm/llvm-project/pull/173364.diff


4 Files Affected:

- (modified) llvm/lib/Target/AArch64/AArch64InstrGISel.td (+14) 
- (modified) llvm/lib/Target/AArch64/GISel/AArch64LegalizerInfo.cpp (+14) 
- (modified) llvm/lib/Target/AArch64/GISel/AArch64RegisterBankInfo.cpp (+4) 
- (modified) llvm/test/CodeGen/AArch64/arm64-vshift.ll (+116-15) 


``````````diff
diff --git a/llvm/lib/Target/AArch64/AArch64InstrGISel.td b/llvm/lib/Target/AArch64/AArch64InstrGISel.td
index 742141b28c502..497306dabaa97 100644
--- a/llvm/lib/Target/AArch64/AArch64InstrGISel.td
+++ b/llvm/lib/Target/AArch64/AArch64InstrGISel.td
@@ -270,6 +270,18 @@ def G_URSHR_I: AArch64GenericInstruction {
   let hasSideEffects = 0;
 }
 
+def G_SLI: AArch64GenericInstruction {
+  let OutOperandList = (outs type0:$dst);
+  let InOperandList = (ins type0:$src1, type0:$src2, type1:$src3);
+  let hasSideEffects = 0;
+}
+
+def G_SRI: AArch64GenericInstruction {
+  let OutOperandList = (outs type0:$dst);
+  let InOperandList = (ins type0:$src1, type0:$src2, type1:$src3);
+  let hasSideEffects = 0;
+}
+
 // Generic instruction for the BSP pseudo. It is expanded into BSP, which
 // expands into BSL/BIT/BIF after register allocation.
 def G_BSP : AArch64GenericInstruction {
@@ -321,6 +333,8 @@ def : GINodeEquiv<G_USDOT, AArch64usdot>;
 def : GINodeEquiv<G_SQSHLU_I, AArch64sqshlui>;
 def : GINodeEquiv<G_SRSHR_I, AArch64srshri>;
 def : GINodeEquiv<G_URSHR_I, AArch64urshri>;
+def : GINodeEquiv<G_SLI, AArch64vsli>;
+def : GINodeEquiv<G_SRI, AArch64vsri>;
 
 def : GINodeEquiv<G_EXTRACT_VECTOR_ELT, vector_extract>;
 
diff --git a/llvm/lib/Target/AArch64/GISel/AArch64LegalizerInfo.cpp b/llvm/lib/Target/AArch64/GISel/AArch64LegalizerInfo.cpp
index fa12818390bdd..1ae0b99416a29 100644
--- a/llvm/lib/Target/AArch64/GISel/AArch64LegalizerInfo.cpp
+++ b/llvm/lib/Target/AArch64/GISel/AArch64LegalizerInfo.cpp
@@ -1949,6 +1949,20 @@ bool AArch64LegalizerInfo::legalizeIntrinsic(LegalizerHelper &Helper,
     }
     return false;
   }
+  case Intrinsic::aarch64_neon_vsli: {
+    MIB.buildInstr(
+        AArch64::G_SLI, {MI.getOperand(0)},
+        {MI.getOperand(2), MI.getOperand(3), MI.getOperand(4).getImm()});
+    MI.eraseFromParent();
+    break;
+  }
+  case Intrinsic::aarch64_neon_vsri: {
+    MIB.buildInstr(
+        AArch64::G_SRI, {MI.getOperand(0)},
+        {MI.getOperand(2), MI.getOperand(3), MI.getOperand(4).getImm()});
+    MI.eraseFromParent();
+    break;
+  }
   case Intrinsic::aarch64_neon_abs: {
     // Lower the intrinsic to G_ABS.
     MIB.buildInstr(TargetOpcode::G_ABS, {MI.getOperand(0)}, {MI.getOperand(2)});
diff --git a/llvm/lib/Target/AArch64/GISel/AArch64RegisterBankInfo.cpp b/llvm/lib/Target/AArch64/GISel/AArch64RegisterBankInfo.cpp
index f21f6023dc181..c5885b53b513b 100644
--- a/llvm/lib/Target/AArch64/GISel/AArch64RegisterBankInfo.cpp
+++ b/llvm/lib/Target/AArch64/GISel/AArch64RegisterBankInfo.cpp
@@ -575,6 +575,8 @@ bool AArch64RegisterBankInfo::onlyUsesFP(const MachineInstr &MI,
   case TargetOpcode::G_LROUND:
   case TargetOpcode::G_LLROUND:
   case AArch64::G_PMULL:
+  case AArch64::G_SLI:
+  case AArch64::G_SRI:
     return true;
   case TargetOpcode::G_INTRINSIC:
     switch (cast<GIntrinsic>(MI).getIntrinsicID()) {
@@ -613,6 +615,8 @@ bool AArch64RegisterBankInfo::onlyDefinesFP(const MachineInstr &MI,
   case TargetOpcode::G_INSERT_VECTOR_ELT:
   case TargetOpcode::G_BUILD_VECTOR:
   case TargetOpcode::G_BUILD_VECTOR_TRUNC:
+  case AArch64::G_SLI:
+  case AArch64::G_SRI:
     return true;
   case TargetOpcode::G_INTRINSIC_W_SIDE_EFFECTS:
     switch (cast<GIntrinsic>(MI).getIntrinsicID()) {
diff --git a/llvm/test/CodeGen/AArch64/arm64-vshift.ll b/llvm/test/CodeGen/AArch64/arm64-vshift.ll
index a316a4bc543b5..c5d2fb1d3749d 100644
--- a/llvm/test/CodeGen/AArch64/arm64-vshift.ll
+++ b/llvm/test/CodeGen/AArch64/arm64-vshift.ll
@@ -2,15 +2,12 @@
 ; RUN: llc < %s -mtriple=arm64-eabi -global-isel=0 | FileCheck %s --check-prefixes=CHECK,CHECK-SD
 ; RUN: llc < %s -mtriple=arm64-eabi -global-isel=1 -global-isel-abort=2 2>&1 | FileCheck %s --check-prefixes=CHECK,CHECK-GI
 
-; CHECK-GI:    warning: Instruction selection used fallback path for sli8b
-; CHECK-GI NEXT:    warning: Instruction selection used fallback path for sli4h
-; CHECK-GI NEXT:    warning: Instruction selection used fallback path for sli2s
-; CHECK-GI NEXT:    warning: Instruction selection used fallback path for sli1d
-; CHECK-GI NEXT:    warning: Instruction selection used fallback path for sli1d_imm0
-; CHECK-GI NEXT:    warning: Instruction selection used fallback path for sli16b
-; CHECK-GI NEXT:    warning: Instruction selection used fallback path for sli8h
-; CHECK-GI NEXT:    warning: Instruction selection used fallback path for sli4s
-; CHECK-GI NEXT:    warning: Instruction selection used fallback path for sli2d
+; CHECK-GI:    warning: Instruction selection used fallback path for sqshrn1s
+; CHECK-GI-NEXT:    warning: Instruction selection used fallback path for sqshrun1s
+; CHECK-GI-NEXT:    warning: Instruction selection used fallback path for sqrshrn1s
+; CHECK-GI-NEXT:    warning: Instruction selection used fallback path for sqrshrun1s
+; CHECK-GI-NEXT:    warning: Instruction selection used fallback path for uqrshrn1s
+; CHECK-GI-NEXT:    warning: Instruction selection used fallback path for uqshrn1s
 
 define <8 x i8> @sqshl8b(ptr %A, ptr %B) nounwind {
 ; CHECK-LABEL: sqshl8b:
@@ -4288,6 +4285,110 @@ declare <8 x i16> @llvm.aarch64.neon.vsli.v8i16(<8 x i16>, <8 x i16>, i32) nounw
 declare <4 x i32> @llvm.aarch64.neon.vsli.v4i32(<4 x i32>, <4 x i32>, i32) nounwind readnone
 declare <2 x i64> @llvm.aarch64.neon.vsli.v2i64(<2 x i64>, <2 x i64>, i32) nounwind readnone
 
+define <8 x i8> @sri8b(ptr %A, ptr %B) nounwind {
+; CHECK-LABEL: sri8b:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    ldr d0, [x0]
+; CHECK-NEXT:    ldr d1, [x1]
+; CHECK-NEXT:    sri v0.8b, v1.8b, #1
+; CHECK-NEXT:    ret
+  %tmp1 = load <8 x i8>, ptr %A
+  %tmp2 = load <8 x i8>, ptr %B
+  %tmp3 = call <8 x i8> @llvm.aarch64.neon.vsri.v8i8(<8 x i8> %tmp1, <8 x i8> %tmp2, i32 1)
+  ret <8 x i8> %tmp3
+}
+
+define <4 x i16> @sri4h(ptr %A, ptr %B) nounwind {
+; CHECK-LABEL: sri4h:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    ldr d0, [x0]
+; CHECK-NEXT:    ldr d1, [x1]
+; CHECK-NEXT:    sri v0.4h, v1.4h, #1
+; CHECK-NEXT:    ret
+  %tmp1 = load <4 x i16>, ptr %A
+  %tmp2 = load <4 x i16>, ptr %B
+  %tmp3 = call <4 x i16> @llvm.aarch64.neon.vsri.v4i16(<4 x i16> %tmp1, <4 x i16> %tmp2, i32 1)
+  ret <4 x i16> %tmp3
+}
+
+define <2 x i32> @sri2s(ptr %A, ptr %B) nounwind {
+; CHECK-LABEL: sri2s:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    ldr d0, [x0]
+; CHECK-NEXT:    ldr d1, [x1]
+; CHECK-NEXT:    sri v0.2s, v1.2s, #1
+; CHECK-NEXT:    ret
+  %tmp1 = load <2 x i32>, ptr %A
+  %tmp2 = load <2 x i32>, ptr %B
+  %tmp3 = call <2 x i32> @llvm.aarch64.neon.vsri.v2i32(<2 x i32> %tmp1, <2 x i32> %tmp2, i32 1)
+  ret <2 x i32> %tmp3
+}
+
+define <1 x i64> @sri1d(ptr %A, ptr %B) nounwind {
+; CHECK-LABEL: sri1d:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    ldr d0, [x0]
+; CHECK-NEXT:    ldr d1, [x1]
+; CHECK-NEXT:    sri d0, d1, #1
+; CHECK-NEXT:    ret
+  %tmp1 = load <1 x i64>, ptr %A
+  %tmp2 = load <1 x i64>, ptr %B
+  %tmp3 = call <1 x i64> @llvm.aarch64.neon.vsri.v1i64(<1 x i64> %tmp1, <1 x i64> %tmp2, i32 1)
+  ret <1 x i64> %tmp3
+}
+
+define <16 x i8> @sri16b(ptr %A, ptr %B) nounwind {
+; CHECK-LABEL: sri16b:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    ldr q0, [x0]
+; CHECK-NEXT:    ldr q1, [x1]
+; CHECK-NEXT:    sri v0.16b, v1.16b, #1
+; CHECK-NEXT:    ret
+  %tmp1 = load <16 x i8>, ptr %A
+  %tmp2 = load <16 x i8>, ptr %B
+  %tmp3 = call <16 x i8> @llvm.aarch64.neon.vsri.v16i8(<16 x i8> %tmp1, <16 x i8> %tmp2, i32 1)
+  ret <16 x i8> %tmp3
+}
+
+define <8 x i16> @sri8h(ptr %A, ptr %B) nounwind {
+; CHECK-LABEL: sri8h:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    ldr q0, [x0]
+; CHECK-NEXT:    ldr q1, [x1]
+; CHECK-NEXT:    sri v0.8h, v1.8h, #1
+; CHECK-NEXT:    ret
+  %tmp1 = load <8 x i16>, ptr %A
+  %tmp2 = load <8 x i16>, ptr %B
+  %tmp3 = call <8 x i16> @llvm.aarch64.neon.vsri.v8i16(<8 x i16> %tmp1, <8 x i16> %tmp2, i32 1)
+  ret <8 x i16> %tmp3
+}
+
+define <4 x i32> @sri4s(ptr %A, ptr %B) nounwind {
+; CHECK-LABEL: sri4s:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    ldr q0, [x0]
+; CHECK-NEXT:    ldr q1, [x1]
+; CHECK-NEXT:    sri v0.4s, v1.4s, #1
+; CHECK-NEXT:    ret
+  %tmp1 = load <4 x i32>, ptr %A
+  %tmp2 = load <4 x i32>, ptr %B
+  %tmp3 = call <4 x i32> @llvm.aarch64.neon.vsri.v4i32(<4 x i32> %tmp1, <4 x i32> %tmp2, i32 1)
+  ret <4 x i32> %tmp3
+}
+
+define <2 x i64> @sri2d(ptr %A, ptr %B) nounwind {
+; CHECK-LABEL: sri2d:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    ldr q0, [x0]
+; CHECK-NEXT:    ldr q1, [x1]
+; CHECK-NEXT:    sri v0.2d, v1.2d, #1
+; CHECK-NEXT:    ret
+  %tmp1 = load <2 x i64>, ptr %A
+  %tmp2 = load <2 x i64>, ptr %B
+  %tmp3 = call <2 x i64> @llvm.aarch64.neon.vsri.v2i64(<2 x i64> %tmp1, <2 x i64> %tmp2, i32 1)
+  ret <2 x i64> %tmp3
+}
+
 define <1 x i64> @ashr_v1i64(<1 x i64> %a, <1 x i64> %b) {
 ; CHECK-SD-LABEL: ashr_v1i64:
 ; CHECK-SD:       // %bb.0:
@@ -4532,9 +4633,9 @@ define <4 x i16> @lshr_trunc_v4i64_v4i16(<4 x i64> %a) {
 ;
 ; CHECK-GI-LABEL: lshr_trunc_v4i64_v4i16:
 ; CHECK-GI:       // %bb.0:
-; CHECK-GI-NEXT:    adrp x8, .LCPI270_0
+; CHECK-GI-NEXT:    adrp x8, .LCPI278_0
 ; CHECK-GI-NEXT:    uzp1 v0.4s, v0.4s, v1.4s
-; CHECK-GI-NEXT:    ldr q2, [x8, :lo12:.LCPI270_0]
+; CHECK-GI-NEXT:    ldr q2, [x8, :lo12:.LCPI278_0]
 ; CHECK-GI-NEXT:    uzp1 v2.4s, v2.4s, v2.4s
 ; CHECK-GI-NEXT:    neg v1.4s, v2.4s
 ; CHECK-GI-NEXT:    ushl v0.4s, v0.4s, v1.4s
@@ -4573,9 +4674,9 @@ define <4 x i16> @ashr_trunc_v4i64_v4i16(<4 x i64> %a) {
 ;
 ; CHECK-GI-LABEL: ashr_trunc_v4i64_v4i16:
 ; CHECK-GI:       // %bb.0:
-; CHECK-GI-NEXT:    adrp x8, .LCPI272_0
+; CHECK-GI-NEXT:    adrp x8, .LCPI280_0
 ; CHECK-GI-NEXT:    uzp1 v0.4s, v0.4s, v1.4s
-; CHECK-GI-NEXT:    ldr q2, [x8, :lo12:.LCPI272_0]
+; CHECK-GI-NEXT:    ldr q2, [x8, :lo12:.LCPI280_0]
 ; CHECK-GI-NEXT:    uzp1 v2.4s, v2.4s, v2.4s
 ; CHECK-GI-NEXT:    neg v1.4s, v2.4s
 ; CHECK-GI-NEXT:    sshl v0.4s, v0.4s, v1.4s
@@ -4613,9 +4714,9 @@ define <4 x i16> @shl_trunc_v4i64_v4i16(<4 x i64> %a) {
 ;
 ; CHECK-GI-LABEL: shl_trunc_v4i64_v4i16:
 ; CHECK-GI:       // %bb.0:
-; CHECK-GI-NEXT:    adrp x8, .LCPI274_0
+; CHECK-GI-NEXT:    adrp x8, .LCPI282_0
 ; CHECK-GI-NEXT:    uzp1 v0.4s, v0.4s, v1.4s
-; CHECK-GI-NEXT:    ldr q2, [x8, :lo12:.LCPI274_0]
+; CHECK-GI-NEXT:    ldr q2, [x8, :lo12:.LCPI282_0]
 ; CHECK-GI-NEXT:    uzp1 v1.4s, v2.4s, v2.4s
 ; CHECK-GI-NEXT:    xtn v0.4h, v0.4s
 ; CHECK-GI-NEXT:    xtn v1.4h, v1.4s

``````````

</details>


https://github.com/llvm/llvm-project/pull/173364


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