Commit d0f8047d authored by Craig Topper's avatar Craig Topper
Browse files

[RISCV] Teach computeKnownBitsForTargetNode that VLENB will never be more than 65536/8.

parent f44fc351

llvm/lib/Target/RISCV/RISCVISelLowering.cpp

+2 −0
Original line number Diff line number Diff line
@@ -6452,6 +6452,8 @@ void RISCVTargetLowering::computeKnownBitsForTargetNode(const SDValue Op, 
  case RISCVISD::READ_VLENB:

    // We assume VLENB is at least 16 bytes.

    Known.Zero.setLowBits(4);

    // We assume VLENB is no more than 65536 / 8 bytes.

    Known.Zero.setBitsFrom(14);

    break;

  case ISD::INTRINSIC_W_CHAIN: {

    unsigned IntNo = Op.getConstantOperandVal(1);

llvm/test/CodeGen/RISCV/rvv/rvv-vscale.i64.ll

+3 −3
Original line number Diff line number Diff line
@@ -50,9 +50,9 @@ define i64 @vscale_uimmpow2xlen() nounwind { 
;

; RV32-LABEL: vscale_uimmpow2xlen:

; RV32:       # %bb.0: # %entry

; RV32-NEXT:    csrr a1, vlenb

; RV32-NEXT:    slli a0, a1, 3

; RV32-NEXT:    srli a1, a1, 29

; RV32-NEXT:    csrr a0, vlenb

; RV32-NEXT:    slli a0, a0, 3

; RV32-NEXT:    mv a1, zero

; RV32-NEXT:    ret

entry:

  %0 = call i64 @llvm.vscale.i64()