[RISCV] Add support for fixed vector fabs

Author: topperc

llvm/lib/Target/RISCV/RISCVISelLowering.cpp

@@ -577,6 +577,7 @@ RISCVTargetLowering::RISCVTargetLowering(const TargetMachine &TM,
         setOperationAction(ISD::FMUL, VT, Custom);
         setOperationAction(ISD::FDIV, VT, Custom);
         setOperationAction(ISD::FNEG, VT, Custom);
+        setOperationAction(ISD::FABS, VT, Custom);
         setOperationAction(ISD::FSQRT, VT, Custom);
         setOperationAction(ISD::FMA, VT, Custom);
       }
@@ -1210,6 +1211,8 @@ SDValue RISCVTargetLowering::LowerOperation(SDValue Op,
     return lowerToScalableOp(Op, DAG, RISCVISD::FDIV_VL);
   case ISD::FNEG:
     return lowerToScalableOp(Op, DAG, RISCVISD::FNEG_VL);
+  case ISD::FABS:
+    return lowerToScalableOp(Op, DAG, RISCVISD::FABS_VL);
   case ISD::FSQRT:
     return lowerToScalableOp(Op, DAG, RISCVISD::FSQRT_VL);
   case ISD::FMA:
@@ -4742,6 +4745,7 @@ const char *RISCVTargetLowering::getTargetNodeName(unsigned Opcode) const {
   NODE_NAME_CASE(FMUL_VL)
   NODE_NAME_CASE(FDIV_VL)
   NODE_NAME_CASE(FNEG_VL)
+  NODE_NAME_CASE(FABS_VL)
   NODE_NAME_CASE(FSQRT_VL)
   NODE_NAME_CASE(FMA_VL)
   NODE_NAME_CASE(SMIN_VL)

llvm/lib/Target/RISCV/RISCVISelLowering.h

@@ -162,6 +162,7 @@ enum NodeType : unsigned {
   FMUL_VL,
   FDIV_VL,
   FNEG_VL,
+  FABS_VL,
   FSQRT_VL,
   FMA_VL,
   SMIN_VL,

llvm/lib/Target/RISCV/RISCVInstrInfoVVLPatterns.td

@@ -73,6 +73,7 @@ def riscv_fsub_vl  : SDNode<"RISCVISD::FSUB_VL",  SDT_RISCVFPBinOp_VL>;
 def riscv_fmul_vl  : SDNode<"RISCVISD::FMUL_VL",  SDT_RISCVFPBinOp_VL, [SDNPCommutative]>;
 def riscv_fdiv_vl  : SDNode<"RISCVISD::FDIV_VL",  SDT_RISCVFPBinOp_VL>;
 def riscv_fneg_vl  : SDNode<"RISCVISD::FNEG_VL",  SDT_RISCVFPUnOp_VL>;
+def riscv_fabs_vl  : SDNode<"RISCVISD::FABS_VL",  SDT_RISCVFPUnOp_VL>;
 def riscv_fsqrt_vl : SDNode<"RISCVISD::FSQRT_VL", SDT_RISCVFPUnOp_VL>;
 
 def SDT_RISCVVecFMA_VL : SDTypeProfile<1, 5, [SDTCisSameAs<0, 1>,
@@ -449,6 +450,10 @@ foreach vti = AllFloatVectors in {
                  vti.RegClass:$rs2, GPR:$vl, vti.SEW)>;
 
   // 14.12. Vector Floating-Point Sign-Injection Instructions
+  def : Pat<(riscv_fabs_vl (vti.Vector vti.RegClass:$rs), (vti.Mask true_mask),
+                           (XLenVT (VLOp GPR:$vl))),
+            (!cast<Instruction>("PseudoVFSGNJX_VV_"# vti.LMul.MX)
+                 vti.RegClass:$rs, vti.RegClass:$rs, GPR:$vl, vti.SEW)>;
   // Handle fneg with VFSGNJN using the same input for both operands.
   def : Pat<(riscv_fneg_vl (vti.Vector vti.RegClass:$rs), (vti.Mask true_mask),
                            (XLenVT (VLOp GPR:$vl))),

llvm/test/CodeGen/RISCV/rvv/fixed-vectors-fp.ll

@@ -253,6 +253,54 @@ define void @fneg_v2f64(<2 x double>* %x) {
   ret void
 }
 
+define void @fabs_v8f16(<8 x half>* %x) {
+; CHECK-LABEL: fabs_v8f16:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    addi a1, zero, 8
+; CHECK-NEXT:    vsetvli a1, a1, e16,m1,ta,mu
+; CHECK-NEXT:    vle16.v v25, (a0)
+; CHECK-NEXT:    vfsgnjx.vv v25, v25, v25
+; CHECK-NEXT:    vse16.v v25, (a0)
+; CHECK-NEXT:    ret
+  %a = load <8 x half>, <8 x half>* %x
+  %b = call <8 x half> @llvm.fabs.v8f16(<8 x half> %a)
+  store <8 x half> %b, <8 x half>* %x
+  ret void
+}
+declare <8 x half> @llvm.fabs.v8f16(<8 x half>)
+
+define void @fabs_v4f32(<4 x float>* %x) {
+; CHECK-LABEL: fabs_v4f32:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    addi a1, zero, 4
+; CHECK-NEXT:    vsetvli a1, a1, e32,m1,ta,mu
+; CHECK-NEXT:    vle32.v v25, (a0)
+; CHECK-NEXT:    vfsgnjx.vv v25, v25, v25
+; CHECK-NEXT:    vse32.v v25, (a0)
+; CHECK-NEXT:    ret
+  %a = load <4 x float>, <4 x float>* %x
+  %b = call <4 x float> @llvm.fabs.v4f32(<4 x float> %a)
+  store <4 x float> %b, <4 x float>* %x
+  ret void
+}
+declare <4 x float> @llvm.fabs.v4f32(<4 x float>)
+
+define void @fabs_v2f64(<2 x double>* %x) {
+; CHECK-LABEL: fabs_v2f64:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    addi a1, zero, 2
+; CHECK-NEXT:    vsetvli a1, a1, e64,m1,ta,mu
+; CHECK-NEXT:    vle64.v v25, (a0)
+; CHECK-NEXT:    vfsgnjx.vv v25, v25, v25
+; CHECK-NEXT:    vse64.v v25, (a0)
+; CHECK-NEXT:    ret
+  %a = load <2 x double>, <2 x double>* %x
+  %b = call <2 x double> @llvm.fabs.v2f64(<2 x double> %a)
+  store <2 x double> %b, <2 x double>* %x
+  ret void
+}
+declare <2 x double> @llvm.fabs.v2f64(<2 x double>)
+
 define void @sqrt_v8f16(<8 x half>* %x) {
 ; CHECK-LABEL: sqrt_v8f16:
 ; CHECK:       # %bb.0: