[RISCV] Support i32 clmul* intrinsics on RV64.

[craig.topper]

Summary

We can use an i64 clmul to emulate i32 clmul.
For clmulh and clmulr we need to zero extend the 32 bit input
to 64 bits then extract either bits [63:32] or [62:31].

Unfortunately, without Zba we need to use 2 shifts for the
zero extends. These can be optimized out later if the producing
instruction already zeroed the upper bits or if we can use lwu.

There are alternative sequences we can use for clmulh/clmulr
when the zero extend isn't free, but those are best handled by
a DAG combine to give the best opportunity for removing the extend.

This allows us to implement i32 clmul C intrinsics proposed in
https://github.com/riscv-non-isa/riscv-c-api-doc/pull/44.

[craig.topper]

Ping

[asb]

LGTM.

llvm/lib/Target/RISCV/RISCVISelLowering.h

 //===-- RISCVISelLowering.h - RISC-V DAG Lowering Interface -----*- C++ -*-===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 //
enum NodeType : unsigned {
   // (returns (Lo, Hi)). It takes a chain operand.
   READ_CYCLE_WIDE,
   // brev8, orc.b, zip, and unzip from Zbb and Zbkb. All operands are i32 or
   // XLenVT.
   BREV8,
   ORC_B,
   ZIP,
   UNZIP,
+
+  // Scalar cryptography
+  CLMUL, CLMULH, CLMULR,
+
   // Vector Extension
   // VMV_V_V_VL matches the semantics of vmv.v.v but includes an extra operand
   // for the VL value to be used for the operation. The first operand is
   // passthru operand.
   VMV_V_V_VL,
   // VMV_V_X_VL matches the semantics of vmv.v.x but includes an extra operand
   // for the VL value to be used for the operation. The first operand is
   // passthru operand.

llvm/lib/Target/RISCV/RISCVISelLowering.cpp

 //===-- RISCVISelLowering.cpp - RISC-V DAG Lowering Implementation  -------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 //
case Intrinsic::riscv_brev8: {
     return DAG.getNode(Opc, DL, XLenVT, Op.getOperand(1));
   }
   case Intrinsic::riscv_zip:
   case Intrinsic::riscv_unzip: {
     unsigned Opc =
         IntNo == Intrinsic::riscv_zip ? RISCVISD::ZIP : RISCVISD::UNZIP;
     return DAG.getNode(Opc, DL, XLenVT, Op.getOperand(1));
   }
+  case Intrinsic::riscv_clmul:
+    return DAG.getNode(RISCVISD::CLMUL, DL, XLenVT, Op.getOperand(1),
+                       Op.getOperand(2));
+  case Intrinsic::riscv_clmulh:
+    return DAG.getNode(RISCVISD::CLMULH, DL, XLenVT, Op.getOperand(1),
+                       Op.getOperand(2));
+  case Intrinsic::riscv_clmulr:
+    return DAG.getNode(RISCVISD::CLMULR, DL, XLenVT, Op.getOperand(1),
+                       Op.getOperand(2));
   case Intrinsic::experimental_get_vector_length:
     return lowerGetVectorLength(Op.getNode(), DAG, Subtarget);
   case Intrinsic::riscv_vmv_x_s:
     assert(Op.getValueType() == XLenVT && "Unexpected VT!");
     return DAG.getNode(RISCVISD::VMV_X_S, DL, Op.getValueType(),
                        Op.getOperand(1));
   case Intrinsic::riscv_vfmv_f_s:
     return DAG.getNode(ISD::EXTRACT_VECTOR_ELT, DL, Op.getValueType(),
case Intrinsic::riscv_brev8: {
       unsigned Opc =
           IntNo == Intrinsic::riscv_brev8 ? RISCVISD::BREV8 : RISCVISD::ORC_B;
       SDValue NewOp =
           DAG.getNode(ISD::ANY_EXTEND, DL, MVT::i64, N->getOperand(1));
       SDValue Res = DAG.getNode(Opc, DL, MVT::i64, NewOp);
       Results.push_back(DAG.getNode(ISD::TRUNCATE, DL, MVT::i32, Res));
       return;
     }
+    case Intrinsic::riscv_clmul: {
+      if (!Subtarget.is64Bit() || N->getValueType(0) != MVT::i32)
+        return;
+
+      SDValue NewOp0 =
+          DAG.getNode(ISD::ANY_EXTEND, DL, MVT::i64, N->getOperand(1));
+      SDValue NewOp1 =
+          DAG.getNode(ISD::ANY_EXTEND, DL, MVT::i64, N->getOperand(2));
+      SDValue Res = DAG.getNode(RISCVISD::CLMUL, DL, MVT::i64, NewOp0, NewOp1);
+      Results.push_back(DAG.getNode(ISD::TRUNCATE, DL, MVT::i32, Res));
+      return;
+    }
+    case Intrinsic::riscv_clmulh:
+    case Intrinsic::riscv_clmulr: {
+      if (!Subtarget.is64Bit() || N->getValueType(0) != MVT::i32)
+        return;
+
+      SDValue NewOp0 =
+          DAG.getNode(ISD::ZERO_EXTEND, DL, MVT::i64, N->getOperand(1));
+      SDValue NewOp1 =
+          DAG.getNode(ISD::ZERO_EXTEND, DL, MVT::i64, N->getOperand(2));
+      SDValue Res = DAG.getNode(RISCVISD::CLMUL, DL, MVT::i64, NewOp0, NewOp1);
+      unsigned ShAmt = IntNo == Intrinsic::riscv_clmulh ? 32 : 31;
+      Res = DAG.getNode(ISD::SRL, DL, MVT::i64, Res,
+                        DAG.getConstant(ShAmt, DL, MVT::i64));
+      Results.push_back(DAG.getNode(ISD::TRUNCATE, DL, MVT::i32, Res));
+      return;
+    }
     case Intrinsic::riscv_vmv_x_s: {
       EVT VT = N->getValueType(0);
       MVT XLenVT = Subtarget.getXLenVT();
       if (VT.bitsLT(XLenVT)) {
         // Simple case just extract using vmv.x.s and truncate.
         SDValue Extract = DAG.getNode(RISCVISD::VMV_X_S, DL,
                                       Subtarget.getXLenVT(), N->getOperand(1));
         Results.push_back(DAG.getNode(ISD::TRUNCATE, DL, VT, Extract));
#define NODE_NAME_CASE(NODE)                                                   \
   NODE_NAME_CASE(STRICT_FCVT_WU_RV64)
   NODE_NAME_CASE(FROUND)
   NODE_NAME_CASE(FPCLASS)
   NODE_NAME_CASE(READ_CYCLE_WIDE)
   NODE_NAME_CASE(BREV8)
   NODE_NAME_CASE(ORC_B)
   NODE_NAME_CASE(ZIP)
   NODE_NAME_CASE(UNZIP)
+  NODE_NAME_CASE(CLMUL)
+  NODE_NAME_CASE(CLMULH)
+  NODE_NAME_CASE(CLMULR)
   NODE_NAME_CASE(TH_LWD)
   NODE_NAME_CASE(TH_LWUD)
   NODE_NAME_CASE(TH_LDD)
   NODE_NAME_CASE(TH_SWD)
   NODE_NAME_CASE(TH_SDD)
   NODE_NAME_CASE(VMV_V_V_VL)
   NODE_NAME_CASE(VMV_V_X_VL)
   NODE_NAME_CASE(VFMV_V_F_VL)

llvm/lib/Target/RISCV/RISCVInstrInfoZb.td

 def riscv_ctzw   : SDNode<"RISCVISD::CTZW",   SDT_RISCVIntUnaryOpW>;
 def riscv_rolw   : SDNode<"RISCVISD::ROLW",   SDT_RISCVIntBinOpW>;
 def riscv_rorw   : SDNode<"RISCVISD::RORW",   SDT_RISCVIntBinOpW>;
 def riscv_brev8  : SDNode<"RISCVISD::BREV8",  SDTIntUnaryOp>;
 def riscv_orc_b  : SDNode<"RISCVISD::ORC_B",  SDTIntUnaryOp>;
 def riscv_zip    : SDNode<"RISCVISD::ZIP",    SDTIntUnaryOp>;
 def riscv_unzip  : SDNode<"RISCVISD::UNZIP",  SDTIntUnaryOp>;
 def riscv_absw   : SDNode<"RISCVISD::ABSW",   SDTIntUnaryOp>;
+def riscv_clmul  : SDNode<"RISCVISD::CLMUL",  SDTIntBinOp>;
+def riscv_clmulh : SDNode<"RISCVISD::CLMULH", SDTIntBinOp>;
+def riscv_clmulr : SDNode<"RISCVISD::CLMULR", SDTIntBinOp>;
 
 def UImmLog2XLenHalfAsmOperand : AsmOperandClass {
   let Name = "UImmLog2XLenHalf";
   let RenderMethod = "addImmOperands";
   let DiagnosticType = "InvalidUImmLog2XLenHalf";
 }
 
 def shfl_uimm : Operand<XLenVT>, ImmLeaf<XLenVT, [{
def : Pat<(i64 (mul (and_oneuse GPR:$r, 0xFFFFFFFF), C5LeftShiftUW:$i)),
           (SH2ADD (SLLI_UW GPR:$r, (TrailingZeros C5LeftShiftUW:$i)),
                   (SLLI_UW GPR:$r, (TrailingZeros C5LeftShiftUW:$i)))>;
 def : Pat<(i64 (mul (and_oneuse GPR:$r, 0xFFFFFFFF), C9LeftShiftUW:$i)),
           (SH3ADD (SLLI_UW GPR:$r, (TrailingZeros C9LeftShiftUW:$i)),
                   (SLLI_UW GPR:$r, (TrailingZeros C9LeftShiftUW:$i)))>;
 } // Predicates = [HasStdExtZba, IsRV64]
 
 let Predicates = [HasStdExtZbcOrZbkc] in {
-def : PatGprGpr<int_riscv_clmul, CLMUL>;
-def : PatGprGpr<int_riscv_clmulh, CLMULH>;
+def : PatGprGpr<riscv_clmul, CLMUL>;
+def : PatGprGpr<riscv_clmulh, CLMULH>;
 } // Predicates = [HasStdExtZbcOrZbkc]
 
 let Predicates = [HasStdExtZbc] in
-def : PatGprGpr<int_riscv_clmulr, CLMULR>;
+def : PatGprGpr<riscv_clmulr, CLMULR>;
 
 let Predicates = [HasStdExtZbkx] in {
 def : PatGprGpr<int_riscv_xperm4, XPERM4>;
 def : PatGprGpr<int_riscv_xperm8, XPERM8>;
 } // Predicates = [HasStdExtZbkx]

llvm/test/CodeGen/RISCV/rv64zbc-intrinsic.ll

 ; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
 ; RUN: llc -mtriple=riscv64 -mattr=+zbc -verify-machineinstrs < %s \
 ; RUN:   | FileCheck %s -check-prefix=RV64ZBC
 
 declare i64 @llvm.riscv.clmulr.i64(i64 %a, i64 %b)
 
 define i64 @clmul64r(i64 %a, i64 %b) nounwind {
 ; RV64ZBC-LABEL: clmul64r:
 ; RV64ZBC:       # %bb.0:
 ; RV64ZBC-NEXT:    clmulr a0, a0, a1
 ; RV64ZBC-NEXT:    ret
   %tmp = call i64 @llvm.riscv.clmulr.i64(i64 %a, i64 %b)
   ret i64 %tmp
 }
+
+declare i32 @llvm.riscv.clmulr.i32(i32 %a, i32 %b)
+
+define signext i32 @clmul32r(i32 signext %a, i32 signext %b) nounwind {
+; RV64ZBC-LABEL: clmul32r:
+; RV64ZBC:       # %bb.0:
+; RV64ZBC-NEXT:    slli a1, a1, 32
+; RV64ZBC-NEXT:    srli a1, a1, 32
+; RV64ZBC-NEXT:    slli a0, a0, 32
+; RV64ZBC-NEXT:    srli a0, a0, 32
+; RV64ZBC-NEXT:    clmul a0, a0, a1
+; RV64ZBC-NEXT:    srli a0, a0, 31
+; RV64ZBC-NEXT:    sext.w a0, a0
+; RV64ZBC-NEXT:    ret
+  %tmp = call i32 @llvm.riscv.clmulr.i32(i32 %a, i32 %b)
+  ret i32 %tmp
+}

llvm/test/CodeGen/RISCV/rv64zbc-zbkc-intrinsic.ll

 ; RV64ZBC-ZBKC-LABEL: clmul64h:
 ; RV64ZBC-ZBKC:       # %bb.0:
 ; RV64ZBC-ZBKC-NEXT:    clmulh a0, a0, a1
 ; RV64ZBC-ZBKC-NEXT:    ret
   %tmp = call i64 @llvm.riscv.clmulh.i64(i64 %a, i64 %b)
   ret i64 %tmp
 }
 
+declare i32 @llvm.riscv.clmul.i32(i32 %a, i32 %b)
+
+define signext i32 @clmul32(i32 signext %a, i32 signext %b) nounwind {
+; RV64ZBC-ZBKC-LABEL: clmul32:
+; RV64ZBC-ZBKC:       # %bb.0:
+; RV64ZBC-ZBKC-NEXT:    clmul a0, a0, a1
+; RV64ZBC-ZBKC-NEXT:    sext.w a0, a0
+; RV64ZBC-ZBKC-NEXT:    ret
+  %tmp = call i32 @llvm.riscv.clmul.i32(i32 %a, i32 %b)
+  ret i32 %tmp
+}
+
+declare i32 @llvm.riscv.clmulh.i32(i32 %a, i32 %b)
+
+define signext i32 @clmul32h(i32 signext %a, i32 signext %b) nounwind {
+; RV64ZBC-ZBKC-LABEL: clmul32h:
+; RV64ZBC-ZBKC:       # %bb.0:
+; RV64ZBC-ZBKC-NEXT:    slli a1, a1, 32
+; RV64ZBC-ZBKC-NEXT:    srli a1, a1, 32
+; RV64ZBC-ZBKC-NEXT:    slli a0, a0, 32
+; RV64ZBC-ZBKC-NEXT:    srli a0, a0, 32
+; RV64ZBC-ZBKC-NEXT:    clmul a0, a0, a1
+; RV64ZBC-ZBKC-NEXT:    srai a0, a0, 32
+; RV64ZBC-ZBKC-NEXT:    ret
+  %tmp = call i32 @llvm.riscv.clmulh.i32(i32 %a, i32 %b)
+  ret i32 %tmp
+}
+