[AArch64][SVE] Add patterns for bit-select instructions. (#138689)

rj-jesus · web-flow · commit 2ec13c513fb9 · 2025-05-12T10:57:18.000+01:00
This patch adds patterns to select SVE2 bit-sel instructions such as BSL
from (or (and a, c), (and b, (vnot c)))) and other similar patterns. For
example:
```cpp
svuint64_t bsl(svuint64_t a, svuint64_t b, svuint64_t c) {
  return (a &amp; c) | (b &amp; ~c);
}
```
Currently:
```gas
bsl:
  and     z0.d, z2.d, z0.d
  bic     z1.d, z1.d, z2.d
  orr     z0.d, z0.d, z1.d
  ret
```
Becomes:
```gas
bsl:
  bsl     z0.d, z0.d, z1.d, z2.d
  ret
```
diff --git a/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp b/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
@@ -21997,6 +21997,30 @@ SDValue tryLowerPartialReductionToWideAdd(SDNode *N,
   return DAG.getNode(TopOpcode, DL, AccVT, BottomNode, ExtOp);
 }
 
+static SDValue combineSVEBitSel(unsigned IID, SDNode *N, SelectionDAG &DAG) {
+  SDLoc DL(N);
+  EVT VT = N->getValueType(0);
+  SDValue Op1 = N->getOperand(1);
+  SDValue Op2 = N->getOperand(2);
+  SDValue Op3 = N->getOperand(3);
+
+  switch (IID) {
+  default:
+    llvm_unreachable("Called with wrong intrinsic!");
+  case Intrinsic::aarch64_sve_bsl:
+    return DAG.getNode(AArch64ISD::BSP, DL, VT, Op3, Op1, Op2);
+  case Intrinsic::aarch64_sve_bsl1n:
+    return DAG.getNode(AArch64ISD::BSP, DL, VT, Op3, DAG.getNOT(DL, Op1, VT),
+                       Op2);
+  case Intrinsic::aarch64_sve_bsl2n:
+    return DAG.getNode(AArch64ISD::BSP, DL, VT, Op3, Op1,
+                       DAG.getNOT(DL, Op2, VT));
+  case Intrinsic::aarch64_sve_nbsl:
+    return DAG.getNOT(DL, DAG.getNode(AArch64ISD::BSP, DL, VT, Op3, Op1, Op2),
+                      VT);
+  }
+}
+
 static SDValue performIntrinsicCombine(SDNode *N,
                                        TargetLowering::DAGCombinerInfo &DCI,
                                        const AArch64Subtarget *Subtarget) {
@@ -22319,6 +22343,11 @@ static SDValue performIntrinsicCombine(SDNode *N,
                     AArch64CC::LAST_ACTIVE);
   case Intrinsic::aarch64_sve_whilelo:
     return tryCombineWhileLo(N, DCI, Subtarget);
+  case Intrinsic::aarch64_sve_bsl:
+  case Intrinsic::aarch64_sve_bsl1n:
+  case Intrinsic::aarch64_sve_bsl2n:
+  case Intrinsic::aarch64_sve_nbsl:
+    return combineSVEBitSel(IID, N, DAG);
   }
   return SDValue();
 }
diff --git a/llvm/lib/Target/AArch64/AArch64SVEInstrInfo.td b/llvm/lib/Target/AArch64/AArch64SVEInstrInfo.td
@@ -545,12 +545,18 @@ def AArch64umulh : PatFrag<(ops node:$op1, node:$op2),
 
 
 def AArch64bsl  : PatFrags<(ops node:$Op1, node:$Op2, node:$Op3),
-                           [(int_aarch64_sve_bsl node:$Op1, node:$Op2, node:$Op3),
-                            (AArch64bsp node:$Op3, node:$Op1, node:$Op2)]>;
+                           [(AArch64bsp node:$Op3, node:$Op1, node:$Op2),
+                            (or (and node:$Op1, node:$Op3), (and node:$Op2, (vnot node:$Op3)))]>;
 
-def AArch64nbsl : PatFrags<(ops node:$Op1, node:$Op2, node:$Op3),
-                           [(int_aarch64_sve_nbsl node:$Op1, node:$Op2, node:$Op3),
-                            (vnot (AArch64bsp node:$Op3, node:$Op1, node:$Op2))]>;
+def AArch64bsl1n : PatFrag<(ops node:$Op1, node:$Op2, node:$Op3),
+                           (AArch64bsl (vnot node:$Op1), node:$Op2, node:$Op3)>;
+
+def AArch64bsl2n : PatFrags<(ops node:$Op1, node:$Op2, node:$Op3),
+                            [(AArch64bsl node:$Op1, (vnot node:$Op2), node:$Op3),
+                             (or (and node:$Op1, node:$Op3), (vnot (or node:$Op2, node:$Op3)))]>;
+
+def AArch64nbsl : PatFrag<(ops node:$Op1, node:$Op2, node:$Op3),
+                          (vnot (AArch64bsl node:$Op1, node:$Op2, node:$Op3))>;
 
 
 let Predicates = [HasSVE] in {
@@ -3934,8 +3940,8 @@ let Predicates = [HasSVE2_or_SME] in {
   defm EOR3_ZZZZ  : sve2_int_bitwise_ternary_op<0b000, "eor3",  AArch64eor3>;
   defm BCAX_ZZZZ  : sve2_int_bitwise_ternary_op<0b010, "bcax",  AArch64bcax>;
   defm BSL_ZZZZ   : sve2_int_bitwise_ternary_op<0b001, "bsl",   AArch64bsl>;
-  defm BSL1N_ZZZZ : sve2_int_bitwise_ternary_op<0b011, "bsl1n", int_aarch64_sve_bsl1n>;
-  defm BSL2N_ZZZZ : sve2_int_bitwise_ternary_op<0b101, "bsl2n", int_aarch64_sve_bsl2n>;
+  defm BSL1N_ZZZZ : sve2_int_bitwise_ternary_op<0b011, "bsl1n", AArch64bsl1n>;
+  defm BSL2N_ZZZZ : sve2_int_bitwise_ternary_op<0b101, "bsl2n", AArch64bsl2n>;
   defm NBSL_ZZZZ  : sve2_int_bitwise_ternary_op<0b111, "nbsl",  AArch64nbsl>;
 
   // SVE2 bitwise xor and rotate right by immediate
diff --git a/llvm/test/CodeGen/AArch64/sve2-bsl.ll b/llvm/test/CodeGen/AArch64/sve2-bsl.ll
@@ -93,3 +93,209 @@ define <vscale x 2 x i64> @nbsl_i64(<vscale x 2 x i64> %a, <vscale x 2 x i64> %b
   %4 = xor <vscale x 2 x i64> %3, splat(i64 -1)
   ret <vscale x 2 x i64> %4
 }
+
+; Test BSL/NBSL/BSL1N/BSL2N code generation for:
+;   #define BSL(x,y,z)   (  ((x) & (z)) | ( (y) & ~(z)))
+;   #define NBSL(x,y,z)  (~(((x) & (z)) | ( (y) & ~(z))))
+;   #define BSL1N(x,y,z) ( (~(x) & (z)) | ( (y) & ~(z)))
+;   #define BSL2N(x,y,z) (  ((x) & (z)) | (~(y) & ~(z)))
+
+define <vscale x 16 x i8> @codegen_bsl_i8(<vscale x 16 x i8> %0, <vscale x 16 x i8> %1, <vscale x 16 x i8> %2) {
+; CHECK-LABEL: codegen_bsl_i8:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    bsl z0.d, z0.d, z1.d, z2.d
+; CHECK-NEXT:    ret
+  %4 = and <vscale x 16 x i8> %2, %0
+  %5 = xor <vscale x 16 x i8> %2, splat (i8 -1)
+  %6 = and <vscale x 16 x i8> %1, %5
+  %7 = or <vscale x 16 x i8> %4, %6
+  ret <vscale x 16 x i8> %7
+}
+
+define <vscale x 16 x i8> @codegen_nbsl_i8(<vscale x 16 x i8> %0, <vscale x 16 x i8> %1, <vscale x 16 x i8> %2) {
+; CHECK-LABEL: codegen_nbsl_i8:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    nbsl z0.d, z0.d, z1.d, z2.d
+; CHECK-NEXT:    ret
+  %4 = and <vscale x 16 x i8> %2, %0
+  %5 = xor <vscale x 16 x i8> %2, splat (i8 -1)
+  %6 = and <vscale x 16 x i8> %1, %5
+  %7 = or <vscale x 16 x i8> %4, %6
+  %8 = xor <vscale x 16 x i8> %7, splat (i8 -1)
+  ret <vscale x 16 x i8> %8
+}
+
+define <vscale x 16 x i8> @codegen_bsl1n_i8(<vscale x 16 x i8> %0, <vscale x 16 x i8> %1, <vscale x 16 x i8> %2) {
+; CHECK-LABEL: codegen_bsl1n_i8:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    bsl1n z0.d, z0.d, z1.d, z2.d
+; CHECK-NEXT:    ret
+  %4 = xor <vscale x 16 x i8> %0, splat (i8 -1)
+  %5 = and <vscale x 16 x i8> %2, %4
+  %6 = xor <vscale x 16 x i8> %2, splat (i8 -1)
+  %7 = and <vscale x 16 x i8> %1, %6
+  %8 = or <vscale x 16 x i8> %5, %7
+  ret <vscale x 16 x i8> %8
+}
+
+define <vscale x 16 x i8> @codegen_bsl2n_i8(<vscale x 16 x i8> %0, <vscale x 16 x i8> %1, <vscale x 16 x i8> %2) {
+; CHECK-LABEL: codegen_bsl2n_i8:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    bsl2n z0.d, z0.d, z1.d, z2.d
+; CHECK-NEXT:    ret
+  %4 = and <vscale x 16 x i8> %2, %0
+  %5 = or <vscale x 16 x i8> %2, %1
+  %6 = xor <vscale x 16 x i8> %5, splat (i8 -1)
+  %7 = or <vscale x 16 x i8> %4, %6
+  ret <vscale x 16 x i8> %7
+}
+
+define <vscale x 8 x i16> @codegen_bsl_i16(<vscale x 8 x i16> %0, <vscale x 8 x i16> %1, <vscale x 8 x i16> %2) {
+; CHECK-LABEL: codegen_bsl_i16:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    bsl z0.d, z0.d, z1.d, z2.d
+; CHECK-NEXT:    ret
+  %4 = and <vscale x 8 x i16> %2, %0
+  %5 = xor <vscale x 8 x i16> %2, splat (i16 -1)
+  %6 = and <vscale x 8 x i16> %1, %5
+  %7 = or <vscale x 8 x i16> %4, %6
+  ret <vscale x 8 x i16> %7
+}
+
+define <vscale x 8 x i16> @codegen_nbsl_i16(<vscale x 8 x i16> %0, <vscale x 8 x i16> %1, <vscale x 8 x i16> %2) {
+; CHECK-LABEL: codegen_nbsl_i16:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    nbsl z0.d, z0.d, z1.d, z2.d
+; CHECK-NEXT:    ret
+  %4 = and <vscale x 8 x i16> %2, %0
+  %5 = xor <vscale x 8 x i16> %2, splat (i16 -1)
+  %6 = and <vscale x 8 x i16> %1, %5
+  %7 = or <vscale x 8 x i16> %4, %6
+  %8 = xor <vscale x 8 x i16> %7, splat (i16 -1)
+  ret <vscale x 8 x i16> %8
+}
+
+define <vscale x 8 x i16> @codegen_bsl1n_i16(<vscale x 8 x i16> %0, <vscale x 8 x i16> %1, <vscale x 8 x i16> %2) {
+; CHECK-LABEL: codegen_bsl1n_i16:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    bsl1n z0.d, z0.d, z1.d, z2.d
+; CHECK-NEXT:    ret
+  %4 = xor <vscale x 8 x i16> %0, splat (i16 -1)
+  %5 = and <vscale x 8 x i16> %2, %4
+  %6 = xor <vscale x 8 x i16> %2, splat (i16 -1)
+  %7 = and <vscale x 8 x i16> %1, %6
+  %8 = or <vscale x 8 x i16> %5, %7
+  ret <vscale x 8 x i16> %8
+}
+
+define <vscale x 8 x i16> @codegen_bsl2n_i16(<vscale x 8 x i16> %0, <vscale x 8 x i16> %1, <vscale x 8 x i16> %2) {
+; CHECK-LABEL: codegen_bsl2n_i16:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    bsl2n z0.d, z0.d, z1.d, z2.d
+; CHECK-NEXT:    ret
+  %4 = and <vscale x 8 x i16> %2, %0
+  %5 = or <vscale x 8 x i16> %2, %1
+  %6 = xor <vscale x 8 x i16> %5, splat (i16 -1)
+  %7 = or <vscale x 8 x i16> %4, %6
+  ret <vscale x 8 x i16> %7
+}
+
+define <vscale x 4 x i32> @codegen_bsl_i32(<vscale x 4 x i32> %0, <vscale x 4 x i32> %1, <vscale x 4 x i32> %2) {
+; CHECK-LABEL: codegen_bsl_i32:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    bsl z0.d, z0.d, z1.d, z2.d
+; CHECK-NEXT:    ret
+  %4 = and <vscale x 4 x i32> %2, %0
+  %5 = xor <vscale x 4 x i32> %2, splat (i32 -1)
+  %6 = and <vscale x 4 x i32> %1, %5
+  %7 = or <vscale x 4 x i32> %4, %6
+  ret <vscale x 4 x i32> %7
+}
+
+define <vscale x 4 x i32> @codegen_nbsl_i32(<vscale x 4 x i32> %0, <vscale x 4 x i32> %1, <vscale x 4 x i32> %2) {
+; CHECK-LABEL: codegen_nbsl_i32:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    nbsl z0.d, z0.d, z1.d, z2.d
+; CHECK-NEXT:    ret
+  %4 = and <vscale x 4 x i32> %2, %0
+  %5 = xor <vscale x 4 x i32> %2, splat (i32 -1)
+  %6 = and <vscale x 4 x i32> %1, %5
+  %7 = or <vscale x 4 x i32> %4, %6
+  %8 = xor <vscale x 4 x i32> %7, splat (i32 -1)
+  ret <vscale x 4 x i32> %8
+}
+
+define <vscale x 4 x i32> @codegen_bsl1n_i32(<vscale x 4 x i32> %0, <vscale x 4 x i32> %1, <vscale x 4 x i32> %2) {
+; CHECK-LABEL: codegen_bsl1n_i32:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    bsl1n z0.d, z0.d, z1.d, z2.d
+; CHECK-NEXT:    ret
+  %4 = xor <vscale x 4 x i32> %0, splat (i32 -1)
+  %5 = and <vscale x 4 x i32> %2, %4
+  %6 = xor <vscale x 4 x i32> %2, splat (i32 -1)
+  %7 = and <vscale x 4 x i32> %1, %6
+  %8 = or <vscale x 4 x i32> %5, %7
+  ret <vscale x 4 x i32> %8
+}
+
+define <vscale x 4 x i32> @codegen_bsl2n_i32(<vscale x 4 x i32> %0, <vscale x 4 x i32> %1, <vscale x 4 x i32> %2) {
+; CHECK-LABEL: codegen_bsl2n_i32:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    bsl2n z0.d, z0.d, z1.d, z2.d
+; CHECK-NEXT:    ret
+  %4 = and <vscale x 4 x i32> %2, %0
+  %5 = or <vscale x 4 x i32> %2, %1
+  %6 = xor <vscale x 4 x i32> %5, splat (i32 -1)
+  %7 = or <vscale x 4 x i32> %4, %6
+  ret <vscale x 4 x i32> %7
+}
+
+define <vscale x 2 x i64> @codegen_bsl_i64(<vscale x 2 x i64> %0, <vscale x 2 x i64> %1, <vscale x 2 x i64> %2) {
+; CHECK-LABEL: codegen_bsl_i64:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    bsl z0.d, z0.d, z1.d, z2.d
+; CHECK-NEXT:    ret
+  %4 = and <vscale x 2 x i64> %2, %0
+  %5 = xor <vscale x 2 x i64> %2, splat (i64 -1)
+  %6 = and <vscale x 2 x i64> %1, %5
+  %7 = or <vscale x 2 x i64> %4, %6
+  ret <vscale x 2 x i64> %7
+}
+
+define <vscale x 2 x i64> @codegen_nbsl_i64(<vscale x 2 x i64> %0, <vscale x 2 x i64> %1, <vscale x 2 x i64> %2) {
+; CHECK-LABEL: codegen_nbsl_i64:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    nbsl z0.d, z0.d, z1.d, z2.d
+; CHECK-NEXT:    ret
+  %4 = and <vscale x 2 x i64> %2, %0
+  %5 = xor <vscale x 2 x i64> %2, splat (i64 -1)
+  %6 = and <vscale x 2 x i64> %1, %5
+  %7 = or <vscale x 2 x i64> %4, %6
+  %8 = xor <vscale x 2 x i64> %7, splat (i64 -1)
+  ret <vscale x 2 x i64> %8
+}
+
+define <vscale x 2 x i64> @codegen_bsl1n_i64(<vscale x 2 x i64> %0, <vscale x 2 x i64> %1, <vscale x 2 x i64> %2) {
+; CHECK-LABEL: codegen_bsl1n_i64:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    bsl1n z0.d, z0.d, z1.d, z2.d
+; CHECK-NEXT:    ret
+  %4 = xor <vscale x 2 x i64> %0, splat (i64 -1)
+  %5 = and <vscale x 2 x i64> %2, %4
+  %6 = xor <vscale x 2 x i64> %2, splat (i64 -1)
+  %7 = and <vscale x 2 x i64> %1, %6
+  %8 = or <vscale x 2 x i64> %5, %7
+  ret <vscale x 2 x i64> %8
+}
+
+define <vscale x 2 x i64> @codegen_bsl2n_i64(<vscale x 2 x i64> %0, <vscale x 2 x i64> %1, <vscale x 2 x i64> %2) {
+; CHECK-LABEL: codegen_bsl2n_i64:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    bsl2n z0.d, z0.d, z1.d, z2.d
+; CHECK-NEXT:    ret
+  %4 = and <vscale x 2 x i64> %2, %0
+  %5 = or <vscale x 2 x i64> %2, %1
+  %6 = xor <vscale x 2 x i64> %5, splat (i64 -1)
+  %7 = or <vscale x 2 x i64> %4, %6
+  ret <vscale x 2 x i64> %7
+}
