diff --git a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp --- a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp +++ b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp @@ -2186,7 +2186,8 @@ // a single addi instruction. if (((StepOpcode == ISD::MUL && isInt<12>(SplatStepVal)) || (StepOpcode == ISD::SHL && isUInt<5>(SplatStepVal))) && - isPowerOf2_32(StepDenominator) && isInt<5>(Addend)) { + isPowerOf2_32(StepDenominator) && + (SplatStepVal >= 0 || StepDenominator == 1) && isInt<5>(Addend)) { SDValue VID = DAG.getNode(RISCVISD::VID_VL, DL, ContainerVT, Mask, VL); // Convert right out of the scalable type so we can use standard ISD // nodes for the rest of the computation. If we used scalable types with diff --git a/llvm/test/CodeGen/RISCV/rvv/fixed-vectors-int-buildvec.ll b/llvm/test/CodeGen/RISCV/rvv/fixed-vectors-int-buildvec.ll --- a/llvm/test/CodeGen/RISCV/rvv/fixed-vectors-int-buildvec.ll +++ b/llvm/test/CodeGen/RISCV/rvv/fixed-vectors-int-buildvec.ll @@ -746,17 +746,15 @@ ret <4 x i8> } -; FIXME: This is not a valid way to emit this vid sequence: shift-right for -; division only works for non-negative numbers! define <16 x i8> @buildvec_not_vid_v16i8() { ; CHECK-LABEL: buildvec_not_vid_v16i8: ; CHECK: # %bb.0: +; CHECK-NEXT: li a0, 3 ; CHECK-NEXT: vsetivli zero, 16, e8, m1, ta, mu -; CHECK-NEXT: vid.v v8 -; CHECK-NEXT: li a0, -3 -; CHECK-NEXT: vmul.vx v8, v8, a0 -; CHECK-NEXT: vsrl.vi v8, v8, 3 -; CHECK-NEXT: vadd.vi v8, v8, 5 +; CHECK-NEXT: vmv.s.x v9, a0 +; CHECK-NEXT: vmv.v.i v8, 0 +; CHECK-NEXT: vsetivli zero, 7, e8, m1, tu, mu +; CHECK-NEXT: vslideup.vi v8, v9, 6 ; CHECK-NEXT: ret ret <16 x i8> }