diff --git a/llvm/lib/Target/ARM/ARMISelLowering.cpp b/llvm/lib/Target/ARM/ARMISelLowering.cpp index b073c8651dcdb..2d73725291d11 100644 --- a/llvm/lib/Target/ARM/ARMISelLowering.cpp +++ b/llvm/lib/Target/ARM/ARMISelLowering.cpp @@ -5526,6 +5526,21 @@ SDValue ARMTargetLowering::LowerSELECT_CC(SDValue Op, SelectionDAG &DAG) const { SDValue FalseVal = Op.getOperand(3); ConstantSDNode *CFVal = dyn_cast(FalseVal); ConstantSDNode *CTVal = dyn_cast(TrueVal); + ConstantSDNode *RHSC = dyn_cast(RHS); + if (Op.getValueType().isInteger()) { + // Check for sign pattern (SELECT_CC setgt, iN lhs, -1, 1, -1) and transform + // into (OR (ASR lhs, N-1), 1), which requires less instructions for the + // supported types. + if (CC == ISD::SETGT && RHSC && RHSC->isAllOnes() && CTVal && CFVal && + CTVal->isOne() && CFVal->isAllOnes() && + LHS.getValueType() == TrueVal.getValueType()) { + EVT VT = LHS.getValueType(); + SDValue Shift = + DAG.getNode(ISD::SRA, dl, VT, LHS, + DAG.getConstant(VT.getSizeInBits() - 1, dl, VT)); + return DAG.getNode(ISD::OR, dl, VT, Shift, DAG.getConstant(1, dl, VT)); + } + } if (Subtarget->hasV8_1MMainlineOps() && CFVal && CTVal && LHS.getValueType() == MVT::i32 && RHS.getValueType() == MVT::i32) { diff --git a/llvm/test/CodeGen/ARM/cmp-select-sign.ll b/llvm/test/CodeGen/ARM/cmp-select-sign.ll new file mode 100644 index 0000000000000..298a623ed1d87 --- /dev/null +++ b/llvm/test/CodeGen/ARM/cmp-select-sign.ll @@ -0,0 +1,171 @@ +; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py +; RUN: llc -mtriple=armv7a < %s | FileCheck %s --check-prefix=ARM +; RUN: llc -mtriple=armv6m < %s | FileCheck %s --check-prefix=THUMB +; RUN: llc -mtriple=armv7m < %s | FileCheck %s --check-prefix=THUMB2 +; RUN: llc -mtriple=thumbv8.1m.main < %s | FileCheck %s --check-prefix=THUMBV8 + +define i3 @sign_i3(i3 %a) { +; ARM-LABEL: sign_i3: +; ARM: @ %bb.0: +; ARM-NEXT: lsl r0, r0, #29 +; ARM-NEXT: mov r1, #1 +; ARM-NEXT: orr r0, r1, r0, asr #31 +; ARM-NEXT: bx lr +; +; THUMB-LABEL: sign_i3: +; THUMB: @ %bb.0: +; THUMB-NEXT: lsls r0, r0, #29 +; THUMB-NEXT: asrs r1, r0, #31 +; THUMB-NEXT: movs r0, #1 +; THUMB-NEXT: orrs r0, r1 +; THUMB-NEXT: bx lr +; +; THUMB2-LABEL: sign_i3: +; THUMB2: @ %bb.0: +; THUMB2-NEXT: lsls r0, r0, #29 +; THUMB2-NEXT: movs r1, #1 +; THUMB2-NEXT: orr.w r0, r1, r0, asr #31 +; THUMB2-NEXT: bx lr +; +; THUMBV8-LABEL: sign_i3: +; THUMBV8: @ %bb.0: +; THUMBV8-NEXT: lsls r0, r0, #29 +; THUMBV8-NEXT: movs r1, #1 +; THUMBV8-NEXT: orr.w r0, r1, r0, asr #31 +; THUMBV8-NEXT: bx lr + %c = icmp sgt i3 %a, -1 + %res = select i1 %c, i3 1, i3 -1 + ret i3 %res +} + +define i4 @sign_i4(i4 %a) { +; ARM-LABEL: sign_i4: +; ARM: @ %bb.0: +; ARM-NEXT: lsl r0, r0, #28 +; ARM-NEXT: mov r1, #1 +; ARM-NEXT: orr r0, r1, r0, asr #31 +; ARM-NEXT: bx lr +; +; THUMB-LABEL: sign_i4: +; THUMB: @ %bb.0: +; THUMB-NEXT: lsls r0, r0, #28 +; THUMB-NEXT: asrs r1, r0, #31 +; THUMB-NEXT: movs r0, #1 +; THUMB-NEXT: orrs r0, r1 +; THUMB-NEXT: bx lr +; +; THUMB2-LABEL: sign_i4: +; THUMB2: @ %bb.0: +; THUMB2-NEXT: lsls r0, r0, #28 +; THUMB2-NEXT: movs r1, #1 +; THUMB2-NEXT: orr.w r0, r1, r0, asr #31 +; THUMB2-NEXT: bx lr +; +; THUMBV8-LABEL: sign_i4: +; THUMBV8: @ %bb.0: +; THUMBV8-NEXT: lsls r0, r0, #28 +; THUMBV8-NEXT: movs r1, #1 +; THUMBV8-NEXT: orr.w r0, r1, r0, asr #31 +; THUMBV8-NEXT: bx lr + %c = icmp sgt i4 %a, -1 + %res = select i1 %c, i4 1, i4 -1 + ret i4 %res +} + +define i8 @sign_i8(i8 %a) { +; ARM-LABEL: sign_i8: +; ARM: @ %bb.0: +; ARM-NEXT: lsl r0, r0, #24 +; ARM-NEXT: mov r1, #1 +; ARM-NEXT: orr r0, r1, r0, asr #31 +; ARM-NEXT: bx lr +; +; THUMB-LABEL: sign_i8: +; THUMB: @ %bb.0: +; THUMB-NEXT: lsls r0, r0, #24 +; THUMB-NEXT: asrs r1, r0, #31 +; THUMB-NEXT: movs r0, #1 +; THUMB-NEXT: orrs r0, r1 +; THUMB-NEXT: bx lr +; +; THUMB2-LABEL: sign_i8: +; THUMB2: @ %bb.0: +; THUMB2-NEXT: lsls r0, r0, #24 +; THUMB2-NEXT: movs r1, #1 +; THUMB2-NEXT: orr.w r0, r1, r0, asr #31 +; THUMB2-NEXT: bx lr +; +; THUMBV8-LABEL: sign_i8: +; THUMBV8: @ %bb.0: +; THUMBV8-NEXT: lsls r0, r0, #24 +; THUMBV8-NEXT: movs r1, #1 +; THUMBV8-NEXT: orr.w r0, r1, r0, asr #31 +; THUMBV8-NEXT: bx lr + %c = icmp sgt i8 %a, -1 + %res = select i1 %c, i8 1, i8 -1 + ret i8 %res +} + +define i16 @sign_i16(i16 %a) { +; ARM-LABEL: sign_i16: +; ARM: @ %bb.0: +; ARM-NEXT: lsl r0, r0, #16 +; ARM-NEXT: mov r1, #1 +; ARM-NEXT: orr r0, r1, r0, asr #31 +; ARM-NEXT: bx lr +; +; THUMB-LABEL: sign_i16: +; THUMB: @ %bb.0: +; THUMB-NEXT: lsls r0, r0, #16 +; THUMB-NEXT: asrs r1, r0, #31 +; THUMB-NEXT: movs r0, #1 +; THUMB-NEXT: orrs r0, r1 +; THUMB-NEXT: bx lr +; +; THUMB2-LABEL: sign_i16: +; THUMB2: @ %bb.0: +; THUMB2-NEXT: lsls r0, r0, #16 +; THUMB2-NEXT: movs r1, #1 +; THUMB2-NEXT: orr.w r0, r1, r0, asr #31 +; THUMB2-NEXT: bx lr +; +; THUMBV8-LABEL: sign_i16: +; THUMBV8: @ %bb.0: +; THUMBV8-NEXT: lsls r0, r0, #16 +; THUMBV8-NEXT: movs r1, #1 +; THUMBV8-NEXT: orr.w r0, r1, r0, asr #31 +; THUMBV8-NEXT: bx lr + %c = icmp sgt i16 %a, -1 + %res = select i1 %c, i16 1, i16 -1 + ret i16 %res +} + +define i32 @sign_i32(i32 %a) { +; ARM-LABEL: sign_i32: +; ARM: @ %bb.0: +; ARM-NEXT: mov r1, #1 +; ARM-NEXT: orr r0, r1, r0, asr #31 +; ARM-NEXT: bx lr +; +; THUMB-LABEL: sign_i32: +; THUMB: @ %bb.0: +; THUMB-NEXT: asrs r1, r0, #31 +; THUMB-NEXT: movs r0, #1 +; THUMB-NEXT: orrs r0, r1 +; THUMB-NEXT: bx lr +; +; THUMB2-LABEL: sign_i32: +; THUMB2: @ %bb.0: +; THUMB2-NEXT: movs r1, #1 +; THUMB2-NEXT: orr.w r0, r1, r0, asr #31 +; THUMB2-NEXT: bx lr +; +; THUMBV8-LABEL: sign_i32: +; THUMBV8: @ %bb.0: +; THUMBV8-NEXT: movs r1, #1 +; THUMBV8-NEXT: orr.w r0, r1, r0, asr #31 +; THUMBV8-NEXT: bx lr + %c = icmp sgt i32 %a, -1 + %res = select i1 %c, i32 1, i32 -1 + ret i32 %res +}