diff --git a/library/alloc/src/string.rs b/library/alloc/src/string.rs
index 9a161d057db09..1a0b3b43eb698 100644
--- a/library/alloc/src/string.rs
+++ b/library/alloc/src/string.rs
@@ -2824,7 +2824,54 @@ impl SpecToString for bool {
}
}
+macro_rules! impl_to_string {
+ ($($signed:ident, $unsigned:ident,)*) => {
+ $(
+ #[cfg(not(no_global_oom_handling))]
+ #[cfg(not(feature = "optimize_for_size"))]
+ impl SpecToString for $signed {
+ #[inline]
+ fn spec_to_string(&self) -> String {
+ const SIZE: usize = $signed::MAX.ilog(10) as usize + 1;
+ let mut buf = [core::mem::MaybeUninit::<u8>::uninit(); SIZE];
+ // Only difference between signed and unsigned are these 8 lines.
+ let mut out;
+ if *self < 0 {
+ out = String::with_capacity(SIZE + 1);
+ out.push('-');
+ } else {
+ out = String::with_capacity(SIZE);
+ }
+
+ out.push_str(self.unsigned_abs()._fmt(&mut buf));
+ out
+ }
+ }
+ #[cfg(not(no_global_oom_handling))]
+ #[cfg(not(feature = "optimize_for_size"))]
+ impl SpecToString for $unsigned {
+ #[inline]
+ fn spec_to_string(&self) -> String {
+ const SIZE: usize = $unsigned::MAX.ilog(10) as usize + 1;
+ let mut buf = [core::mem::MaybeUninit::<u8>::uninit(); SIZE];
+
+ self._fmt(&mut buf).to_string()
+ }
+ }
+ )*
+ }
+}
+
+impl_to_string! {
+ i8, u8,
+ i16, u16,
+ i32, u32,
+ i64, u64,
+ isize, usize,
+}
+
#[cfg(not(no_global_oom_handling))]
+#[cfg(feature = "optimize_for_size")]
impl SpecToString for u8 {
#[inline]
fn spec_to_string(&self) -> String {
@@ -2844,6 +2891,7 @@ impl SpecToString for u8 {
}
#[cfg(not(no_global_oom_handling))]
+#[cfg(feature = "optimize_for_size")]
impl SpecToString for i8 {
#[inline]
fn spec_to_string(&self) -> String {
diff --git a/library/core/src/fmt/num.rs b/library/core/src/fmt/num.rs
index 4467b37bd4510..ba30518d70bc2 100644
--- a/library/core/src/fmt/num.rs
+++ b/library/core/src/fmt/num.rs
@@ -208,7 +208,11 @@ macro_rules! impl_Display {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
#[cfg(not(feature = "optimize_for_size"))]
{
- self._fmt(true, f)
+ const MAX_DEC_N: usize = $unsigned::MAX.ilog(10) as usize + 1;
+ // Buffer decimals for $unsigned with right alignment.
+ let mut buf = [MaybeUninit::<u8>::uninit(); MAX_DEC_N];
+
+ f.pad_integral(true, "", self._fmt(&mut buf))
}
#[cfg(feature = "optimize_for_size")]
{
@@ -222,7 +226,11 @@ macro_rules! impl_Display {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
#[cfg(not(feature = "optimize_for_size"))]
{
- return self.unsigned_abs()._fmt(*self >= 0, f);
+ const MAX_DEC_N: usize = $unsigned::MAX.ilog(10) as usize + 1;
+ // Buffer decimals for $unsigned with right alignment.
+ let mut buf = [MaybeUninit::<u8>::uninit(); MAX_DEC_N];
+
+ f.pad_integral(*self >= 0, "", self.unsigned_abs()._fmt(&mut buf))
}
#[cfg(feature = "optimize_for_size")]
{
@@ -233,10 +241,13 @@ macro_rules! impl_Display {
#[cfg(not(feature = "optimize_for_size"))]
impl $unsigned {
- fn _fmt(self, is_nonnegative: bool, f: &mut fmt::Formatter<'_>) -> fmt::Result {
- const MAX_DEC_N: usize = $unsigned::MAX.ilog(10) as usize + 1;
- // Buffer decimals for $unsigned with right alignment.
- let mut buf = [MaybeUninit::<u8>::uninit(); MAX_DEC_N];
+ #[doc(hidden)]
+ #[unstable(
+ feature = "fmt_internals",
+ reason = "specialized method meant to only be used by `SpecToString` implementation",
+ issue = "none"
+ )]
+ pub fn _fmt<'a>(self, buf: &'a mut [MaybeUninit::<u8>]) -> &'a str {
// Count the number of bytes in buf that are not initialized.
let mut offset = buf.len();
// Consume the least-significant decimals from a working copy.
@@ -301,13 +312,12 @@ macro_rules! impl_Display {
// SAFETY: All buf content since offset is set.
let written = unsafe { buf.get_unchecked(offset..) };
// SAFETY: Writes use ASCII from the lookup table exclusively.
- let as_str = unsafe {
+ unsafe {
str::from_utf8_unchecked(slice::from_raw_parts(
MaybeUninit::slice_as_ptr(written),
written.len(),
))
- };
- f.pad_integral(is_nonnegative, "", as_str)
+ }
}
})*
diff --git a/tests/ui/codegen/equal-pointers-unequal/as-cast/inline2.rs b/tests/ui/codegen/equal-pointers-unequal/as-cast/inline2.rs
index 9a1ace86e4db8..5ec3c7cbdf55b 100644
--- a/tests/ui/codegen/equal-pointers-unequal/as-cast/inline2.rs
+++ b/tests/ui/codegen/equal-pointers-unequal/as-cast/inline2.rs
@@ -23,7 +23,7 @@ fn main() {
let v = 0;
&v as *const _ as usize
};
- assert_eq!(a.to_string(), b.to_string());
+ assert_eq!(format!("{a}"), format!("{b}"));
assert_eq!(format!("{}", a == b), "true");
assert_eq!(format!("{}", cmp_in(a, b)), "true");
assert_eq!(format!("{}", cmp(a, b)), "true");
diff --git a/tests/ui/codegen/equal-pointers-unequal/as-cast/zero.rs b/tests/ui/codegen/equal-pointers-unequal/as-cast/zero.rs
index d1aa95a9a569d..731c5b67882bd 100644
--- a/tests/ui/codegen/equal-pointers-unequal/as-cast/zero.rs
+++ b/tests/ui/codegen/equal-pointers-unequal/as-cast/zero.rs
@@ -21,7 +21,7 @@ fn main() {
// It's not zero, which means `a` and `b` are not equal.
assert_ne!(i, 0);
// But it looks like zero...
- assert_eq!(i.to_string(), "0");
+ assert_eq!(format!("{i}"), "0");
// ...and now it *is* zero?
assert_eq!(i, 0);
// So `a` and `b` are equal after all?
diff --git a/tests/ui/codegen/equal-pointers-unequal/exposed-provenance/inline2.rs b/tests/ui/codegen/equal-pointers-unequal/exposed-provenance/inline2.rs
index f128e1bb0841a..94739708ab8bd 100644
--- a/tests/ui/codegen/equal-pointers-unequal/exposed-provenance/inline2.rs
+++ b/tests/ui/codegen/equal-pointers-unequal/exposed-provenance/inline2.rs
@@ -25,7 +25,7 @@ fn main() {
let v = 0;
ptr::from_ref(&v).expose_provenance()
};
- assert_eq!(a.to_string(), b.to_string());
+ assert_eq!(format!("{a}"), format!("{b}"));
assert_eq!(format!("{}", a == b), "true");
assert_eq!(format!("{}", cmp_in(a, b)), "true");
assert_eq!(format!("{}", cmp(a, b)), "true");
diff --git a/tests/ui/codegen/equal-pointers-unequal/exposed-provenance/zero.rs b/tests/ui/codegen/equal-pointers-unequal/exposed-provenance/zero.rs
index 7ccff8d0848e9..b7824f53d77f8 100644
--- a/tests/ui/codegen/equal-pointers-unequal/exposed-provenance/zero.rs
+++ b/tests/ui/codegen/equal-pointers-unequal/exposed-provenance/zero.rs
@@ -23,7 +23,7 @@ fn main() {
// It's not zero, which means `a` and `b` are not equal.
assert_ne!(i, 0);
// But it looks like zero...
- assert_eq!(i.to_string(), "0");
+ assert_eq!(format!("{i}"), "0");
// ...and now it *is* zero?
assert_eq!(i, 0);
// So `a` and `b` are equal after all?
diff --git a/tests/ui/codegen/equal-pointers-unequal/strict-provenance/inline2.rs b/tests/ui/codegen/equal-pointers-unequal/strict-provenance/inline2.rs
index 0414879804a5a..0f838af1fb190 100644
--- a/tests/ui/codegen/equal-pointers-unequal/strict-provenance/inline2.rs
+++ b/tests/ui/codegen/equal-pointers-unequal/strict-provenance/inline2.rs
@@ -25,7 +25,7 @@ fn main() {
let v = 0;
ptr::from_ref(&v).addr()
};
- assert_eq!(a.to_string(), b.to_string());
+ assert_eq!(format!("{a}"), format!("{b}"));
assert_eq!(format!("{}", a == b), "true");
assert_eq!(format!("{}", cmp_in(a, b)), "true");
assert_eq!(format!("{}", cmp(a, b)), "true");
diff --git a/tests/ui/codegen/equal-pointers-unequal/strict-provenance/zero.rs b/tests/ui/codegen/equal-pointers-unequal/strict-provenance/zero.rs
index d963e45e4cdf2..20ed991ed3d66 100644
--- a/tests/ui/codegen/equal-pointers-unequal/strict-provenance/zero.rs
+++ b/tests/ui/codegen/equal-pointers-unequal/strict-provenance/zero.rs
@@ -23,7 +23,7 @@ fn main() {
// It's not zero, which means `a` and `b` are not equal.
assert_ne!(i, 0);
// But it looks like zero...
- assert_eq!(i.to_string(), "0");
+ assert_eq!(format!("{i}"), "0");
// ...and now it *is* zero?
assert_eq!(i, 0);
// So `a` and `b` are equal after all?