[RISCV] Add computeKnownBits support for RISCVISD::GORC.

[craig.topper]

Ping

[luismarques]

LGTM.

It's a weird mix of responsibilities to have a ComputeZeros parameter in a GREV/GORC function but it's very convenient on the caller side :)

llvm/lib/Target/RISCV/RISCVISelLowering.cpp

 //===-- RISCVISelLowering.cpp - RISCV 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
 //
 //===----------------------------------------------------------------------===//
 //
bool RISCVTargetLowering::targetShrinkDemandedConstant(
   else
     return false;
 
   // Check that our new mask is a subset of the demanded mask.
   assert(IsLegalMask(NewMask));
   return UseMask(NewMask);
 }
 
-static void computeGREV(APInt &Src, unsigned ShAmt) {
+static void computeGREVOrGORC(APInt &Src, unsigned ShAmt, bool IsGORC,
+                              bool ComputeZeros = false) {
+  static const uint64_t GREVMasks[] = {
+      0x5555555555555555ULL, 0x3333333333333333ULL, 0x0F0F0F0F0F0F0F0FULL,
+      0x00FF00FF00FF00FFULL, 0x0000FFFF0000FFFFULL, 0x00000000FFFFFFFFULL};
+
   ShAmt &= Src.getBitWidth() - 1;
   uint64_t x = Src.getZExtValue();
-  if (ShAmt & 1)
-    x = ((x & 0x5555555555555555LL) << 1) | ((x & 0xAAAAAAAAAAAAAAAALL) >> 1);
-  if (ShAmt & 2)
-    x = ((x & 0x3333333333333333LL) << 2) | ((x & 0xCCCCCCCCCCCCCCCCLL) >> 2);
-  if (ShAmt & 4)
-    x = ((x & 0x0F0F0F0F0F0F0F0FLL) << 4) | ((x & 0xF0F0F0F0F0F0F0F0LL) >> 4);
-  if (ShAmt & 8)
-    x = ((x & 0x00FF00FF00FF00FFLL) << 8) | ((x & 0xFF00FF00FF00FF00LL) >> 8);
-  if (ShAmt & 16)
-    x = ((x & 0x0000FFFF0000FFFFLL) << 16) | ((x & 0xFFFF0000FFFF0000LL) >> 16);
-  if (ShAmt & 32)
-    x = ((x & 0x00000000FFFFFFFFLL) << 32) | ((x & 0xFFFFFFFF00000000LL) >> 32);
+
+  // To compute zeros, we need to invert the value and invert it back after.
+  if (ComputeZeros)
+    x = ~x;
+
+  for (unsigned Stage = 0; Stage != 6; ++Stage) {
+    unsigned Shift = 1 << Stage;
+    if (ShAmt & Shift) {
+      uint64_t Mask = GREVMasks[Stage];
+      uint64_t Res = ((x & Mask) << Shift) | ((x >> Shift) & Mask);
+      if (IsGORC)
+        Res |= x;
+      x = Res;
+    }
+  }
+
+  if (ComputeZeros)
+    x = ~x;
+
   Src = x;
 }
 
 void RISCVTargetLowering::computeKnownBitsForTargetNode(const SDValue Op,
                                                         KnownBits &Known,
                                                         const APInt &DemandedElts,
                                                         const SelectionDAG &DAG,
                                                         unsigned Depth) const {
case RISCVISD::CLZW: {
     unsigned LowBits = Log2_32(PossibleLZ) + 1;
     Known.Zero.setBitsFrom(LowBits);
     break;
   }
   case RISCVISD::GREV: {
     if (auto *C = dyn_cast<ConstantSDNode>(Op.getOperand(1))) {
       Known = DAG.computeKnownBits(Op.getOperand(0), Depth + 1);
       unsigned ShAmt = C->getZExtValue();
-      computeGREV(Known.Zero, ShAmt);
-      computeGREV(Known.One, ShAmt);
+      computeGREVOrGORC(Known.Zero, ShAmt, /*IsGORC*/ false);
+      computeGREVOrGORC(Known.One, ShAmt, /*IsGORC*/ false);
+    }
+    break;
+  }
+  case RISCVISD::GORC: {
+    if (auto *C = dyn_cast<ConstantSDNode>(Op.getOperand(1))) {
+      Known = DAG.computeKnownBits(Op.getOperand(0), Depth + 1);
+      unsigned ShAmt = C->getZExtValue();
+      computeGREVOrGORC(Known.Zero, ShAmt, /*IsGORC*/ true,
+                        /*ComputeZeros*/ true);
+      computeGREVOrGORC(Known.One, ShAmt, /*IsGORC*/ true);
     }
     break;
   }
   case RISCVISD::READ_VLENB: {
     // If we know the minimum VLen from Zvl extensions, we can use that to
     // determine the trailing zeros of VLENB.
     // FIXME: Limit to 128 bit vectors until we have more testing.
     unsigned MinVLenB = std::min(128U, Subtarget.getMinVLen()) / 8;

llvm/test/CodeGen/RISCV/rv32zbb-intrinsic.ll

 ; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
 ; RUN: llc -mtriple=riscv32 -mattr=+zbb -verify-machineinstrs < %s \
 ; RUN:   | FileCheck %s -check-prefix=RV32ZBB
 
 declare i32 @llvm.riscv.orc.b.i32(i32)
 
 define i32 @orcb(i32 %a) nounwind {
 ; RV32ZBB-LABEL: orcb:
 ; RV32ZBB:       # %bb.0:
 ; RV32ZBB-NEXT:    orc.b a0, a0
 ; RV32ZBB-NEXT:    ret
   %tmp = call i32 @llvm.riscv.orc.b.i32(i32 %a)
   ret i32 %tmp
 }
+
+; Second and+or are redundant with the first, make sure we remove it.
+define i32 @orcb_knownbits(i32 %a) nounwind {
+; RV32ZBB-LABEL: orcb_knownbits:
+; RV32ZBB:       # %bb.0:
+; RV32ZBB-NEXT:    lui a1, 1044480
+; RV32ZBB-NEXT:    and a0, a0, a1
+; RV32ZBB-NEXT:    lui a1, 2048
+; RV32ZBB-NEXT:    addi a1, a1, 1
+; RV32ZBB-NEXT:    or a0, a0, a1
+; RV32ZBB-NEXT:    orc.b a0, a0
+; RV32ZBB-NEXT:    ret
+  %tmp = and i32 %a, 4278190080 ; 0xFF000000
+  %tmp2 = or i32 %tmp, 8388609 ; 0x800001
+  %tmp3 = call i32 @llvm.riscv.orc.b.i32(i32 %tmp2)
+  %tmp4 = and i32 %tmp3, 4278190080 ; 0xFF000000
+  %tmp5 = or i32 %tmp4, 16711935 ; 0xFF00FF
+  ret i32 %tmp5
+}

llvm/test/CodeGen/RISCV/rv64zbb-intrinsic.ll

; RV64ZBP-NEXT:    ret
   %tmp = call i32 @llvm.riscv.orc.b.i32(i32 %a)
   ret i32 %tmp
 }
 
 define zeroext i32 @orcb32_zext(i32 zeroext %a) nounwind {
 ; RV64ZBB-LABEL: orcb32_zext:
 ; RV64ZBB:       # %bb.0:
 ; RV64ZBB-NEXT:    orc.b a0, a0
-; RV64ZBB-NEXT:    slli a0, a0, 32
-; RV64ZBB-NEXT:    srli a0, a0, 32
 ; RV64ZBB-NEXT:    ret
 ;
 ; RV64ZBP-LABEL: orcb32_zext:
 ; RV64ZBP:       # %bb.0:
 ; RV64ZBP-NEXT:    orc.b a0, a0
-; RV64ZBP-NEXT:    slli a0, a0, 32
-; RV64ZBP-NEXT:    srli a0, a0, 32
 ; RV64ZBP-NEXT:    ret
   %tmp = call i32 @llvm.riscv.orc.b.i32(i32 %a)
   ret i32 %tmp
 }
 
+; Second and+or is redundant with the first, make sure we remove them.
+define signext i32 @orcb32_knownbits(i32 signext %a) nounwind {
+; RV64ZBB-LABEL: orcb32_knownbits:
+; RV64ZBB:       # %bb.0:
+; RV64ZBB-NEXT:    lui a1, 1044480
+; RV64ZBB-NEXT:    and a0, a0, a1
+; RV64ZBB-NEXT:    lui a1, 2048
+; RV64ZBB-NEXT:    addiw a1, a1, 1
+; RV64ZBB-NEXT:    or a0, a0, a1
+; RV64ZBB-NEXT:    orc.b a0, a0
+; RV64ZBB-NEXT:    sext.w a0, a0
+; RV64ZBB-NEXT:    ret
+;
+; RV64ZBP-LABEL: orcb32_knownbits:
+; RV64ZBP:       # %bb.0:
+; RV64ZBP-NEXT:    lui a1, 1044480
+; RV64ZBP-NEXT:    and a0, a0, a1
+; RV64ZBP-NEXT:    lui a1, 2048
+; RV64ZBP-NEXT:    addiw a1, a1, 1
+; RV64ZBP-NEXT:    or a0, a0, a1
+; RV64ZBP-NEXT:    gorciw a0, a0, 7
+; RV64ZBP-NEXT:    ret
+  %tmp = and i32 %a, 4278190080 ; 0xFF000000
+  %tmp2 = or i32 %tmp, 8388609 ; 0x800001
+  %tmp3 = call i32 @llvm.riscv.orc.b.i32(i32 %tmp2)
+  %tmp4 = and i32 %tmp3, 4278190080 ; 0xFF000000
+  %tmp5 = or i32 %tmp4, 16711935 ; 0xFF00FF
+  ret i32 %tmp5
+}
+
 declare i64 @llvm.riscv.orc.b.i64(i64)
 
 define i64 @orcb64(i64 %a) nounwind {
 ; RV64ZBB-LABEL: orcb64:
 ; RV64ZBB:       # %bb.0:
 ; RV64ZBB-NEXT:    orc.b a0, a0
 ; RV64ZBB-NEXT:    ret
 ;
 ; RV64ZBP-LABEL: orcb64:
 ; RV64ZBP:       # %bb.0:
 ; RV64ZBP-NEXT:    orc.b a0, a0
 ; RV64ZBP-NEXT:    ret
   %tmp = call i64 @llvm.riscv.orc.b.i64(i64 %a)
   ret i64 %tmp
 }
+
+; Second and+or is redundant with the first, make sure we remove them.
+define i64 @orcb64_knownbits(i64 %a) nounwind {
+; RV64ZBB-LABEL: orcb64_knownbits:
+; RV64ZBB:       # %bb.0:
+; RV64ZBB-NEXT:    lui a1, 65535
+; RV64ZBB-NEXT:    slli a1, a1, 12
+; RV64ZBB-NEXT:    and a0, a0, a1
+; RV64ZBB-NEXT:    lui a1, 131073
+; RV64ZBB-NEXT:    slli a1, a1, 13
+; RV64ZBB-NEXT:    addi a1, a1, 1
+; RV64ZBB-NEXT:    slli a1, a1, 20
+; RV64ZBB-NEXT:    addi a1, a1, 8
+; RV64ZBB-NEXT:    or a0, a0, a1
+; RV64ZBB-NEXT:    orc.b a0, a0
+; RV64ZBB-NEXT:    ret
+;
+; RV64ZBP-LABEL: orcb64_knownbits:
+; RV64ZBP:       # %bb.0:
+; RV64ZBP-NEXT:    lui a1, 65535
+; RV64ZBP-NEXT:    slli a1, a1, 12
+; RV64ZBP-NEXT:    and a0, a0, a1
+; RV64ZBP-NEXT:    lui a1, 131073
+; RV64ZBP-NEXT:    slli a1, a1, 13
+; RV64ZBP-NEXT:    addi a1, a1, 1
+; RV64ZBP-NEXT:    slli a1, a1, 20
+; RV64ZBP-NEXT:    addi a1, a1, 8
+; RV64ZBP-NEXT:    or a0, a0, a1
+; RV64ZBP-NEXT:    orc.b a0, a0
+; RV64ZBP-NEXT:    ret
+  %tmp = and i64 %a, 1099494850560 ; 0x000000ffff000000
+  %tmp2 = or i64 %tmp, 4611721202800525320 ; 0x4000200000100008
+  %tmp3 = call i64 @llvm.riscv.orc.b.i64(i64 %tmp2)
+  %tmp4 = and i64 %tmp3, 1099494850560 ; 0x000000ffff000000
+  %tmp5 = or i64 %tmp4, 18374966855153418495 ; 0xff00ff0000ff00ff
+  ret i64 %tmp5
+}

llvm/test/CodeGen/RISCV/rv64zbp-intrinsic.ll

 ; RV64ZBP-LABEL: gorci32:
 ; RV64ZBP:       # %bb.0:
 ; RV64ZBP-NEXT:    gorciw a0, a0, 13
 ; RV64ZBP-NEXT:    ret
   %tmp = call i32 @llvm.riscv.gorc.i32(i32 %a, i32 13)
   ret i32 %tmp
 }
 
+define zeroext i32 @gorci32_zext(i32 zeroext %a) nounwind {
+; RV64ZBP-LABEL: gorci32_zext:
+; RV64ZBP:       # %bb.0:
+; RV64ZBP-NEXT:    orc.w a0, a0
+; RV64ZBP-NEXT:    ret
+  %tmp = call i32 @llvm.riscv.gorc.i32(i32 %a, i32 31)
+  ret i32 %tmp
+}
+
 declare i32 @llvm.riscv.shfl.i32(i32 %a, i32 %b)
 
 define signext i32 @shfl32(i32 signext %a, i32 signext %b) nounwind {
 ; RV64ZBP-LABEL: shfl32:
 ; RV64ZBP:       # %bb.0:
 ; RV64ZBP-NEXT:    shflw a0, a0, a1
 ; RV64ZBP-NEXT:    ret
   %tmp = call i32 @llvm.riscv.shfl.i32(i32 %a, i32 %b)

 ; RV64ZBP-LABEL: gorci64:
 ; RV64ZBP:       # %bb.0:
 ; RV64ZBP-NEXT:    gorci a0, a0, 13
 ; RV64ZBP-NEXT:    ret
   %tmp = call i64 @llvm.riscv.gorc.i64(i64 %a, i64 13)
   ret i64 %tmp
 }
 
+; The second OR is redundant with the first. Make sure we remove it.
+define i64 @gorci64_knownbits(i64 %a) nounwind {
+; RV64ZBP-LABEL: gorci64_knownbits:
+; RV64ZBP:       # %bb.0:
+; RV64ZBP-NEXT:    lui a1, %hi(.LCPI54_0)
+; RV64ZBP-NEXT:    ld a1, %lo(.LCPI54_0)(a1)
+; RV64ZBP-NEXT:    or a0, a0, a1
+; RV64ZBP-NEXT:    orc32 a0, a0
+; RV64ZBP-NEXT:    ret
+  %tmp = or i64 %a, 72624976668147840 ; 0x102040810204080
+  %tmp2 = call i64 @llvm.riscv.gorc.i64(i64 %tmp, i64 32)
+  %tmp3 = or i64 %tmp2, 1234624599046636680 ; 0x1122448811224488
+  ret i64 %tmp3
+}
+
 define i64 @orchi64(i64 %a) nounwind {
 ; RV64ZBP-LABEL: orchi64:
 ; RV64ZBP:       # %bb.0:
 ; RV64ZBP-NEXT:    orc.h a0, a0
 ; RV64ZBP-NEXT:    ret
   %tmp = call i64 @llvm.riscv.gorc.i64(i64 %a, i64 15)
   ret i64 %tmp
 }