AMDGPU: Move towards deprecating alignbit intrinsic

[arsenm]

Summary

This is equivalent to llvm.fshr, so legalize the intrinsic to the
generic node.

[foad]

Seems pretty obvious to me. Presumably this has no effect on generated code?

[arsenm]

a950e3beefd55c354b658f2ef79a9406289bcc08

llvm/lib/Target/AMDGPU/SIISelLowering.cpp

case Intrinsic::amdgcn_is_private: {
     SDValue Aperture = getSegmentAperture(AS, SL, DAG);
     SDValue SrcVec = DAG.getNode(ISD::BITCAST, DL, MVT::v2i32,
                                  Op.getOperand(1));
 
     SDValue SrcHi = DAG.getNode(ISD::EXTRACT_VECTOR_ELT, SL, MVT::i32, SrcVec,
                                 DAG.getConstant(1, SL, MVT::i32));
     return DAG.getSetCC(SL, MVT::i1, SrcHi, Aperture, ISD::SETEQ);
   }
+  case Intrinsic::amdgcn_alignbit:
+    return DAG.getNode(ISD::FSHR, DL, VT,
+                       Op.getOperand(1), Op.getOperand(2), Op.getOperand(3));
   default:
     if (const AMDGPU::ImageDimIntrinsicInfo *ImageDimIntr =
             AMDGPU::getImageDimIntrinsicInfo(IntrinsicID))
       return lowerImage(Op, ImageDimIntr, DAG);
 
     return Op;
   }
 }

llvm/lib/Target/AMDGPU/SIInstructions.td

 // VOP3 Patterns
 //===----------------------------------------------------------------------===//
 
 def : IMad24Pat<V_MAD_I32_I24, 1>;
 def : UMad24Pat<V_MAD_U32_U24, 1>;
 
 // FIXME: This should only be done for VALU inputs
 defm : BFIPatterns <V_BFI_B32, S_MOV_B32, SReg_64>;
-def : FSHRPattern <V_ALIGNBIT_B32>;
 def : ROTRPattern <V_ALIGNBIT_B32>;
 
 def : GCNPat<(i32 (trunc (srl i64:$src0, (and i32:$src1, (i32 31))))),
           (V_ALIGNBIT_B32 (i32 (EXTRACT_SUBREG (i64 $src0), sub1)),
                           (i32 (EXTRACT_SUBREG (i64 $src0), sub0)), $src1)>;
 
 def : GCNPat<(i32 (trunc (srl i64:$src0, (i32 ShiftAmt32Imm:$src1)))),
           (V_ALIGNBIT_B32 (i32 (EXTRACT_SUBREG (i64 $src0), sub1)),

llvm/lib/Target/AMDGPU/VOP3Instructions.td

 
 def V_CUBEID_F32 : VOP3Inst <"v_cubeid_f32", VOP3_Profile<VOP_F32_F32_F32_F32>, int_amdgcn_cubeid>;
 def V_CUBESC_F32 : VOP3Inst <"v_cubesc_f32", VOP3_Profile<VOP_F32_F32_F32_F32>, int_amdgcn_cubesc>;
 def V_CUBETC_F32 : VOP3Inst <"v_cubetc_f32", VOP3_Profile<VOP_F32_F32_F32_F32>, int_amdgcn_cubetc>;
 def V_CUBEMA_F32 : VOP3Inst <"v_cubema_f32", VOP3_Profile<VOP_F32_F32_F32_F32>, int_amdgcn_cubema>;
 def V_BFE_U32 : VOP3Inst <"v_bfe_u32", VOP3_Profile<VOP_I32_I32_I32_I32>, AMDGPUbfe_u32>;
 def V_BFE_I32 : VOP3Inst <"v_bfe_i32", VOP3_Profile<VOP_I32_I32_I32_I32>, AMDGPUbfe_i32>;
 def V_BFI_B32 : VOP3Inst <"v_bfi_b32", VOP3_Profile<VOP_I32_I32_I32_I32>, AMDGPUbfi>;
-def V_ALIGNBIT_B32 : VOP3Inst <"v_alignbit_b32", VOP3_Profile<VOP_I32_I32_I32_I32>, int_amdgcn_alignbit>;
+def V_ALIGNBIT_B32 : VOP3Inst <"v_alignbit_b32", VOP3_Profile<VOP_I32_I32_I32_I32>, fshr>;
 def V_ALIGNBYTE_B32 : VOP3Inst <"v_alignbyte_b32", VOP3_Profile<VOP_I32_I32_I32_I32>, int_amdgcn_alignbyte>;
 def V_MIN3_F32 : VOP3Inst <"v_min3_f32", VOP3_Profile<VOP_F32_F32_F32_F32>, AMDGPUfmin3>;
 def V_MIN3_I32 : VOP3Inst <"v_min3_i32", VOP3_Profile<VOP_I32_I32_I32_I32>, AMDGPUsmin3>;
 def V_MIN3_U32 : VOP3Inst <"v_min3_u32", VOP3_Profile<VOP_I32_I32_I32_I32>, AMDGPUumin3>;
 def V_MAX3_F32 : VOP3Inst <"v_max3_f32", VOP3_Profile<VOP_F32_F32_F32_F32>, AMDGPUfmax3>;
 def V_MAX3_I32 : VOP3Inst <"v_max3_i32", VOP3_Profile<VOP_I32_I32_I32_I32>, AMDGPUsmax3>;
 def V_MAX3_U32 : VOP3Inst <"v_max3_u32", VOP3_Profile<VOP_I32_I32_I32_I32>, AMDGPUumax3>;
 def V_MED3_F32 : VOP3Inst <"v_med3_f32", VOP3_Profile<VOP_F32_F32_F32_F32>, AMDGPUfmed3>;