]>
Commit | Line | Data |
---|---|---|
29967ef6 XL |
1 | //! Peephole optimizations that can be performed while creating clif ir. |
2 | ||
94222f64 | 3 | use cranelift_codegen::ir::{condcodes::IntCC, InstructionData, Opcode, Value, ValueDef}; |
29967ef6 XL |
4 | use cranelift_frontend::FunctionBuilder; |
5 | ||
29967ef6 XL |
6 | /// If the given value was produced by the lowering of `Rvalue::Not` return the input and true, |
7 | /// otherwise return the given value and false. | |
8 | pub(crate) fn maybe_unwrap_bool_not(bcx: &mut FunctionBuilder<'_>, arg: Value) -> (Value, bool) { | |
9 | if let ValueDef::Result(arg_inst, 0) = bcx.func.dfg.value_def(arg) { | |
10 | match bcx.func.dfg[arg_inst] { | |
11 | // This is the lowering of `Rvalue::Not` | |
12 | InstructionData::IntCompareImm { | |
13 | opcode: Opcode::IcmpImm, | |
14 | cond: IntCC::Equal, | |
15 | arg, | |
16 | imm, | |
17 | } if imm.bits() == 0 => (arg, true), | |
18 | _ => (arg, false), | |
19 | } | |
20 | } else { | |
21 | (arg, false) | |
22 | } | |
23 | } | |
24 | ||
5869c6ff XL |
25 | /// Returns whether the branch is statically known to be taken or `None` if it isn't statically known. |
26 | pub(crate) fn maybe_known_branch_taken( | |
27 | bcx: &FunctionBuilder<'_>, | |
28 | arg: Value, | |
29 | test_zero: bool, | |
30 | ) -> Option<bool> { | |
31 | let arg_inst = if let ValueDef::Result(arg_inst, 0) = bcx.func.dfg.value_def(arg) { | |
32 | arg_inst | |
33 | } else { | |
34 | return None; | |
35 | }; | |
36 | ||
37 | match bcx.func.dfg[arg_inst] { | |
6a06907d | 38 | InstructionData::UnaryImm { opcode: Opcode::Iconst, imm } => { |
5869c6ff XL |
39 | if test_zero { |
40 | Some(imm.bits() == 0) | |
41 | } else { | |
42 | Some(imm.bits() != 0) | |
43 | } | |
44 | } | |
45 | _ => None, | |
46 | } | |
47 | } |