Skip to content

remove incorrectly placed preserves_flags, and other inline asm fixes #1036

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
tgross35 merged 1 commit into from
Dec 6, 2025
Merged

remove incorrectly placed preserves_flags, and other inline asm fixes #1036

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
8 changes: 3 additions & 5 deletions compiler-builtins/src/mem/x86_64.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -23,7 +23,7 @@ use core::{intrinsics, mem};
#[cfg(target_feature = "ermsb")]
pub unsafe fn copy_forward(dest: *mut u8, src: *const u8, count: usize) {
asm!(
"repe movsb [rdi], [rsi]",
"rep movsb [rdi], [rsi]",
inout("rcx") count => _,
inout("rdi") dest => _,
inout("rsi") src => _,
Expand Down Expand Up @@ -70,7 +70,6 @@ pub unsafe fn copy_backward(dest: *mut u8, src: *const u8, count: usize) {
"sub rdi, 7",
"mov rcx, {qword_count:r}",
"rep movsq",
"test {pre_byte_count:e}, {pre_byte_count:e}",
"add rsi, 7",
"add rdi, 7",
"mov ecx, {pre_byte_count:e}",
Expand All @@ -81,16 +80,15 @@ pub unsafe fn copy_backward(dest: *mut u8, src: *const u8, count: usize) {
inout("ecx") byte_count => _,
inout("rdi") dest.add(count - 1) => _,
inout("rsi") src.add(count - 1) => _,
// We modify flags, but we restore it afterwards
options(nostack, preserves_flags)
options(nostack)
);
}

#[inline(always)]
#[cfg(target_feature = "ermsb")]
pub unsafe fn set_bytes(dest: *mut u8, c: u8, count: usize) {
asm!(
"repe stosb [rdi], al",
"rep stosb [rdi], al",
inout("rcx") count => _,
inout("rdi") dest => _,
inout("al") c => _,
Expand Down
Loading