Merge pull request #2614 from kaseyc/nop

Avoid creating 0-sized nops in x64's gen_nop().
This commit is contained in:
Chris Fallin
2021-01-28 21:37:39 -08:00
committed by GitHub
2 changed files with 4 additions and 4 deletions

View File

@@ -566,7 +566,7 @@ impl Inst {
impl Inst {
pub(crate) fn nop(len: u8) -> Self {
debug_assert!(len <= 16);
debug_assert!(len <= 15);
Self::Nop { len }
}
@@ -2602,11 +2602,11 @@ impl MachInst for Inst {
}
fn gen_zero_len_nop() -> Inst {
Inst::Nop { len: 0 }
Inst::nop(0)
}
fn gen_nop(preferred_size: usize) -> Inst {
Inst::nop((preferred_size % 16) as u8)
Inst::nop(std::cmp::min(preferred_size, 15) as u8)
}
fn maybe_direct_reload(&self, _reg: VirtualReg, _slot: SpillSlot) -> Option<Inst> {

View File

@@ -178,7 +178,7 @@ pub trait MachInst: Clone + Debug {
/// request a NOP of that size, or as close to it as possible. The machine
/// backend may return a NOP whose binary encoding is smaller than the
/// preferred size, but must not return a NOP that is larger. However,
/// the instruction must have a nonzero size.
/// the instruction must have a nonzero size if preferred_size is nonzero.
fn gen_nop(preferred_size: usize) -> Self;
/// Get the register universe for this backend.