Merge pull request #3002 from afonso360/aarch64-i128-br

aarch64 implement brz,brnz,br_icmp for i128 values

cranelift/codegen/src/isa/aarch64/lower.rs

@@ -1226,12 +1226,43 @@ pub(crate) fn maybe_input_insn_via_conv<C: LowerCtx<I = Inst>>(
  None
 }
 
-pub(crate) fn lower_icmp_or_ifcmp_to_flags<C: LowerCtx<I = Inst>>(
+/// Specifies what [lower_icmp] should do when lowering
+#[derive(Debug, Clone, PartialEq)]
+pub(crate) enum IcmpOutput {
+ /// Only sets flags, discarding the results
+ Flags,
+ /// Materializes the results into a register. The flags set may be incorrect
+ Register(Writable<Reg>),
+}
+
+impl IcmpOutput {
+ pub fn reg(&self) -> Option<Writable<Reg>> {
+ match self {
+ IcmpOutput::Flags => None,
+ IcmpOutput::Register(reg) => Some(*reg),
+ }
+ }
+}
+
+/// Lower an icmp comparision
+///
+/// We can lower into the status flags, or materialize the result into a register
+/// This is controlled by the `output` parameter.
+pub(crate) fn lower_icmp<C: LowerCtx<I = Inst>>(
  ctx: &mut C,
  insn: IRInst,
- is_signed: bool,
-) {
- debug!("lower_icmp_or_ifcmp_to_flags: insn {}", insn);
+ condcode: IntCC,
+ output: IcmpOutput,
+) -> CodegenResult<()> {
+ debug!(
+ "lower_icmp: insn {}, condcode: {}, output: {:?}",
+ insn, condcode, output
+ );
+
+ let rd = output.reg().unwrap_or(writable_zero_reg());
+ let inputs = insn_inputs(ctx, insn);
+ let cond = lower_condcode(condcode);
+ let is_signed = condcode_is_signed(condcode);
  let ty = ctx.input_ty(insn, 0);
  let bits = ty_bits(ty);
  let narrow_mode = match (bits <= 32, is_signed) {
@@ -1240,14 +1271,149 @@ pub(crate) fn lower_icmp_or_ifcmp_to_flags<C: LowerCtx<I = Inst>>(
  (false, true) => NarrowValueMode::SignExtend64,
  (false, false) => NarrowValueMode::ZeroExtend64,
  };
- let inputs = [InsnInput { insn, input: 0 }, InsnInput { insn, input: 1 }];
- let ty = ctx.input_ty(insn, 0);
- let rn = put_input_in_reg(ctx, inputs[0], narrow_mode);
- let rm = put_input_in_rse_imm12(ctx, inputs[1], narrow_mode);
- debug!("lower_icmp_or_ifcmp_to_flags: rn = {:?} rm = {:?}", rn, rm);
- let alu_op = choose_32_64(ty, ALUOp::SubS32, ALUOp::SubS64);
- let rd = writable_zero_reg();
- ctx.emit(alu_inst_imm12(alu_op, rd, rn, rm));
+
+ if ty == I128 {
+ let lhs = put_input_in_regs(ctx, inputs[0]);
+ let rhs = put_input_in_regs(ctx, inputs[1]);
+
+ let tmp1 = ctx.alloc_tmp(I64).only_reg().unwrap();
+ let tmp2 = ctx.alloc_tmp(I64).only_reg().unwrap();
+
+ match condcode {
+ IntCC::Equal | IntCC::NotEqual => {
+ // eor tmp1, lhs_lo, rhs_lo
+ // eor tmp2, lhs_hi, rhs_hi
+ // adds xzr, tmp1, tmp2
+ // cset dst, {eq, ne}
+
+ ctx.emit(Inst::AluRRR {
+ alu_op: ALUOp::Eor64,
+ rd: tmp1,
+ rn: lhs.regs()[0],
+ rm: rhs.regs()[0],
+ });
+ ctx.emit(Inst::AluRRR {
+ alu_op: ALUOp::Eor64,
+ rd: tmp2,
+ rn: lhs.regs()[1],
+ rm: rhs.regs()[1],
+ });
+ ctx.emit(Inst::AluRRR {
+ alu_op: ALUOp::AddS64,
+ rd: writable_zero_reg(),
+ rn: tmp1.to_reg(),
+ rm: tmp2.to_reg(),
+ });
+
+ if let IcmpOutput::Register(rd) = output {
+ materialize_bool_result(ctx, insn, rd, cond);
+ }
+ }
+ IntCC::Overflow | IntCC::NotOverflow => {
+ // We can do an 128bit add while throwing away the results
+ // and check the overflow flags at the end.
+ //
+ // adds xzr, lhs_lo, rhs_lo
+ // adcs xzr, lhs_hi, rhs_hi
+ // cset dst, {vs, vc}
+
+ ctx.emit(Inst::AluRRR {
+ alu_op: ALUOp::AddS64,
+ rd: writable_zero_reg(),
+ rn: lhs.regs()[0],
+ rm: rhs.regs()[0],
+ });
+ ctx.emit(Inst::AluRRR {
+ alu_op: ALUOp::AdcS64,
+ rd: writable_zero_reg(),
+ rn: lhs.regs()[1],
+ rm: rhs.regs()[1],
+ });
+
+ if let IcmpOutput::Register(rd) = output {
+ materialize_bool_result(ctx, insn, rd, cond);
+ }
+ }
+ _ => {
+ // cmp lhs_lo, rhs_lo
+ // cset tmp1, unsigned_cond
+ // cmp lhs_hi, rhs_hi
+ // cset tmp2, cond
+ // csel dst, tmp1, tmp2, eq
+
+ let rd = output.reg().unwrap_or(tmp1);
+ let unsigned_cond = lower_condcode(condcode.unsigned());
+
+ ctx.emit(Inst::AluRRR {
+ alu_op: ALUOp::SubS64,
+ rd: writable_zero_reg(),
+ rn: lhs.regs()[0],
+ rm: rhs.regs()[0],
+ });
+ materialize_bool_result(ctx, insn, tmp1, unsigned_cond);
+ ctx.emit(Inst::AluRRR {
+ alu_op: ALUOp::SubS64,
+ rd: writable_zero_reg(),
+ rn: lhs.regs()[1],
+ rm: rhs.regs()[1],
+ });
+ materialize_bool_result(ctx, insn, tmp2, cond);
+ ctx.emit(Inst::CSel {
+ cond: Cond::Eq,
+ rd,
+ rn: tmp1.to_reg(),
+ rm: tmp2.to_reg(),
+ });
+
+ if output == IcmpOutput::Flags {
+ // We only need to guarantee that the flags for `cond` are correct, so we can
+ // compare rd with 0 or 1
+
+ // If we are doing compare or equal, we want to compare with 1 instead of zero
+ if condcode.without_equal() != condcode {
+ lower_constant_u64(ctx, tmp2, 1);
+ }
+
+ let xzr = zero_reg();
+ let rd = rd.to_reg();
+ let tmp2 = tmp2.to_reg();
+ let (rn, rm) = match condcode {
+ IntCC::SignedGreaterThanOrEqual => (rd, tmp2),
+ IntCC::UnsignedGreaterThanOrEqual => (rd, tmp2),
+ IntCC::SignedLessThanOrEqual => (tmp2, rd),
+ IntCC::UnsignedLessThanOrEqual => (tmp2, rd),
+ IntCC::SignedGreaterThan => (rd, xzr),
+ IntCC::UnsignedGreaterThan => (rd, xzr),
+ IntCC::SignedLessThan => (xzr, rd),
+ IntCC::UnsignedLessThan => (xzr, rd),
+ _ => unreachable!(),
+ };
+
+ ctx.emit(Inst::AluRRR {
+ alu_op: ALUOp::SubS64,
+ rd: writable_zero_reg(),
+ rn,
+ rm,
+ });
+ }
+ }
+ }
+ } else if !ty.is_vector() {
+ let alu_op = choose_32_64(ty, ALUOp::SubS32, ALUOp::SubS64);
+ let rn = put_input_in_reg(ctx, inputs[0], narrow_mode);
+ let rm = put_input_in_rse_imm12(ctx, inputs[1], narrow_mode);
+ ctx.emit(alu_inst_imm12(alu_op, writable_zero_reg(), rn, rm));
+
+ if let IcmpOutput::Register(rd) = output {
+ materialize_bool_result(ctx, insn, rd, cond);
+ }
+ } else {
+ let rn = put_input_in_reg(ctx, inputs[0], narrow_mode);
+ let rm = put_input_in_reg(ctx, inputs[1], narrow_mode);
+ lower_vector_compare(ctx, rd, rn, rm, ty, cond)?;
+ }
+
+ Ok(())
 }
 
 pub(crate) fn lower_fcmp_or_ffcmp_to_flags<C: LowerCtx<I = Inst>>(ctx: &mut C, insn: IRInst) {