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optimise cmp x, 0; jz

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This commit is contained in:
Fabian 2022-11-04 12:12:04 -06:00
parent 1d55116779
commit 6fcbe7b3d0
2 changed files with 22 additions and 2 deletions
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16
src/rust/codegen.rs
View file

@ -348,6 +348,18 @@ fn gen_get_last_result(builder: &mut WasmBuilder, previous_instruction: &Instruc
dest: InstructionOperandDest::WasmLocal(l),
opsize: OPSIZE_32,
} => builder.get_local(&l),
Instruction::Cmp {
dest: InstructionOperandDest::WasmLocal(l),
source,
opsize: OPSIZE_32,
} => {
if source.is_zero() {
builder.get_local(&l)
}
else {
builder.load_fixed_i32(global_pointers::last_result as u32)
}
},
_ => builder.load_fixed_i32(global_pointers::last_result as u32),
}
}
@ -1582,7 +1594,6 @@ pub fn gen_getzf(ctx: &mut JitContext, negate: ConditionNegate) {
match &ctx.previous_instruction {
Instruction::Cmp { .. } | Instruction::Sub { .. } => {
gen_profiler_stat_increment(ctx.builder, profiler::stat::CONDITION_OPTIMISED);
// TODO: Could use local for cmp x, 0
// TODO: Could use eq(local, local) for cmp x, y
gen_get_last_result(ctx.builder, &ctx.previous_instruction);
if negate == ConditionNegate::False {
@ -1734,7 +1745,8 @@ pub fn gen_getsf(ctx: &mut JitContext) {
let &opsize = opsize;
gen_profiler_stat_increment(ctx.builder, profiler::stat::CONDITION_OPTIMISED);
// TODO:
// Could use local for cmp x, 0; test x, x
// use local for test x, x
// x >= 0 for ConditionNegate::True
gen_get_last_result(ctx.builder, &ctx.previous_instruction);
ctx.builder.const_i32(if opsize == OPSIZE_32 {
0x8000_0000u32 as i32

8
src/rust/jit.rs
View file

@ -244,6 +244,14 @@ pub enum InstructionOperand {
Immediate(i32),
Other,
}
impl InstructionOperand {
pub fn is_zero(&self) -> bool {
match self {
InstructionOperand::Immediate(0) => true,
_ => false,
}
}
}
impl Into<InstructionOperand> for InstructionOperandDest {
fn into(self: InstructionOperandDest) -> InstructionOperand {
match self {