Index: lib/Target/ARM/ARMISelDAGToDAG.cpp =================================================================== --- lib/Target/ARM/ARMISelDAGToDAG.cpp +++ lib/Target/ARM/ARMISelDAGToDAG.cpp @@ -2797,6 +2797,45 @@ if (tryV6T2BitfieldExtractOp(N, false)) return; + // If an immediate is used in an AND node, it is possible that the immediate + // can be more optimally materialized when negated. If this is the case we + // can negate the immediate and use a BIC instead. + auto *N1C = dyn_cast(N->getOperand(1)); + if (N1C && N1C->hasOneUse() && Subtarget->isThumb()) { + uint32_t Imm = (uint32_t) N1C->getZExtValue(); + + // In Thumb2 mode, an AND can take a 12-bit immediate. If this + // immediate can be negated and fit in the immediate operand of + // a t2BIC, don't do any manual transform here as this can be + // handled by the generic ISel machinery. + bool PreferImmediateEncoding = + Subtarget->hasThumb2() && !is_t2_so_imm(Imm) && is_t2_so_imm_not(Imm); + if (!PreferImmediateEncoding && + ConstantMaterializationCost(Imm) > + ConstantMaterializationCost(~Imm)) { + // The current immediate costs more to materialize than a negated + // immediate, so negate the immediate and use a BIC. + SDValue NewImm = + CurDAG->getConstant(~N1C->getZExtValue(), dl, MVT::i32); + CurDAG->RepositionNode(N->getIterator(), NewImm.getNode()); + + if (!Subtarget->hasThumb2()) { + SDValue Ops[] = {CurDAG->getRegister(ARM::CPSR, MVT::i32), + N->getOperand(0), NewImm, getAL(CurDAG, dl), + CurDAG->getRegister(0, MVT::i32)}; + ReplaceNode(N, CurDAG->getMachineNode(ARM::tBIC, dl, MVT::i32, Ops)); + return; + } else { + SDValue Ops[] = {N->getOperand(0), NewImm, getAL(CurDAG, dl), + CurDAG->getRegister(0, MVT::i32), + CurDAG->getRegister(0, MVT::i32)}; + ReplaceNode(N, + CurDAG->getMachineNode(ARM::t2BICrr, dl, MVT::i32, Ops)); + return; + } + } + } + // (and (or x, c2), c1) and top 16-bits of c1 and c2 match, lower 16-bits // of c1 are 0xffff, and lower 16-bit of c2 are 0. That is, the top 16-bits // are entirely contributed by c2 and lower 16-bits are entirely contributed @@ -2811,7 +2850,7 @@ if (!Opc) break; SDValue N0 = N->getOperand(0), N1 = N->getOperand(1); - ConstantSDNode *N1C = dyn_cast(N1); + N1C = dyn_cast(N1); if (!N1C) break; if (N0.getOpcode() == ISD::OR && N0.getNode()->hasOneUse()) { Index: test/CodeGen/Thumb/bic_imm.ll =================================================================== --- /dev/null +++ test/CodeGen/Thumb/bic_imm.ll @@ -0,0 +1,15 @@ +; RUN: llc < %s -mtriple=thumbv7-linux-gnueabi -mcpu=cortex-m0 -verify-machineinstrs | FileCheck --check-prefix CHECK-T1 %s +; RUN: llc < %s -mtriple=thumbv7-linux-gnueabi -mcpu=cortex-m3 -verify-machineinstrs | FileCheck --check-prefix CHECK-T2 %s + +; CHECK-T1-LABEL: @i +; CHECK-T2-LABEL: @i +; CHECK-T1: movs r1, #255 +; CHECK-T1: adds r1, #20 +; CHECK-T1: bics r0, r1 +; CHECK-T2: movw r1, #275 +; CHECK-T2: bics r0, r1 +define i32 @i(i32 %a) { +entry: + %and = and i32 %a, -276 + ret i32 %and +}