T0b1/wasmtime
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

machinst x64: optimize select/brz/brnz when the input is a comparison;

Browse Source
This commit is contained in:
Benjamin Bouvier
2020-08-18 16:30:47 +02:00
parent 620e4b4e82
commit cca10b87cb
4 changed files with 257 additions and 34 deletions
Download Patch File Download Diff File Expand all files Collapse all files

17
cranelift/codegen/src/isa/x64/inst/emit.rs
View File

@@ -1298,6 +1298,8 @@ pub(crate) fn emit(
src,
dst,
} => {
// Lowering of the Select IR opcode when the input is an fcmp relies on the fact that
// this doesn't clobber flags. Make sure to not do so here.
let next = sink.get_label();
// Jump if cc is *not* set.
@@ -1432,6 +1434,21 @@ pub(crate) fn emit(
sink.put4(disp);
}
Inst::JmpIf { cc, taken } => {
let cond_start = sink.cur_offset();
let cond_disp_off = cond_start + 2;
if let Some(l) = taken.as_label() {
sink.use_label_at_offset(cond_disp_off, l, LabelUse::JmpRel32);
// Since this is not a terminator, don't enroll in the branch inversion mechanism.
}
let taken_disp = taken.as_offset32_or_zero();
let taken_disp = taken_disp as u32;
sink.put1(0x0F);
sink.put1(0x80 + cc.get_enc());
sink.put4(taken_disp);
}
Inst::JmpCond {
cc,
taken,