Merge ref 'd087f112b7d1:/library/compiler-builtins' from https://github.com/rust-lang/rust

Pull recent changes from rust-lang/rust via Josh.

Upstream ref: d087f112b7d1323446c7b39a8b616aee7fa56b3d
Filtered ref: 2d43ce8ac022170e5383f7e5a188b55564b6566a

5 files changed, 98 insertions, 43 deletions

diff --git a/compiler/rustc_data_structures/src/lib.rs b/compiler/rustc_data_structures/src/lib.rs
index b7447e24731..eb3817a80a7 100644
--- a/compiler/rustc_data_structures/src/lib.rs
+++ b/compiler/rustc_data_structures/src/lib.rs
@@ -25,7 +25,6 @@
 #![feature(dropck_eyepatch)]
 #![feature(extend_one)]
 #![feature(file_buffered)]
-#![feature(macro_metavar_expr)]
 #![feature(map_try_insert)]
 #![feature(min_specialization)]
 #![feature(negative_impls)]
diff --git a/compiler/rustc_data_structures/src/thousands/mod.rs b/compiler/rustc_data_structures/src/thousands/mod.rs
index e7ab7ec2932..b251ebe58f6 100644
--- a/compiler/rustc_data_structures/src/thousands/mod.rs
+++ b/compiler/rustc_data_structures/src/thousands/mod.rs
@@ -1,16 +1,37 @@
-//! This is an extremely bare-bones alternative to the `thousands` crate on
-//! crates.io, for printing large numbers in a readable fashion.
+//! This is a bare-bones alternative to the `thousands` crate on crates.io, for
+//! printing large numbers in a readable fashion.
 
 #[cfg(test)]
 mod tests;
 
-// Converts the number to a string, with underscores as the thousands separator.
-pub fn format_with_underscores(n: usize) -> String {
-    let mut s = n.to_string();
-    let mut i = s.len();
-    while i > 3 {
+fn format_with_underscores(mut s: String) -> String {
+    // Ignore a leading '-'.
+    let start = if s.starts_with('-') { 1 } else { 0 };
+
+    // Stop after the first non-digit, e.g. '.' or 'e' for floats.
+    let non_digit = s[start..].find(|c: char| !c.is_digit(10));
+    let end = if let Some(non_digit) = non_digit { start + non_digit } else { s.len() };
+
+    // Insert underscores within `start..end`.
+    let mut i = end;
+    while i > start + 3 {
         i -= 3;
         s.insert(i, '_');
     }
     s
 }
+
+/// Print a `usize` with underscore separators.
+pub fn usize_with_underscores(n: usize) -> String {
+    format_with_underscores(format!("{n}"))
+}
+
+/// Print an `isize` with underscore separators.
+pub fn isize_with_underscores(n: isize) -> String {
+    format_with_underscores(format!("{n}"))
+}
+
+/// Print an `f64` with precision 1 (one decimal place) and underscore separators.
+pub fn f64p1_with_underscores(n: f64) -> String {
+    format_with_underscores(format!("{n:.1}"))
+}
diff --git a/compiler/rustc_data_structures/src/thousands/tests.rs b/compiler/rustc_data_structures/src/thousands/tests.rs
index 906605d9a93..0f9a648802b 100644
--- a/compiler/rustc_data_structures/src/thousands/tests.rs
+++ b/compiler/rustc_data_structures/src/thousands/tests.rs
@@ -2,13 +2,51 @@ use super::*;
 
 #[test]
 fn test_format_with_underscores() {
-    assert_eq!("0", format_with_underscores(0));
-    assert_eq!("1", format_with_underscores(1));
-    assert_eq!("99", format_with_underscores(99));
-    assert_eq!("345", format_with_underscores(345));
-    assert_eq!("1_000", format_with_underscores(1_000));
-    assert_eq!("12_001", format_with_underscores(12_001));
-    assert_eq!("999_999", format_with_underscores(999_999));
-    assert_eq!("1_000_000", format_with_underscores(1_000_000));
-    assert_eq!("12_345_678", format_with_underscores(12_345_678));
+    assert_eq!("", format_with_underscores("".to_string()));
+    assert_eq!("0", format_with_underscores("0".to_string()));
+    assert_eq!("12_345.67e14", format_with_underscores("12345.67e14".to_string()));
+    assert_eq!("-1_234.5678e10", format_with_underscores("-1234.5678e10".to_string()));
+    assert_eq!("------", format_with_underscores("------".to_string()));
+    assert_eq!("abcdefgh", format_with_underscores("abcdefgh".to_string()));
+    assert_eq!("-1b", format_with_underscores("-1b".to_string()));
+    assert_eq!("-3_456xyz", format_with_underscores("-3456xyz".to_string()));
+}
+
+#[test]
+fn test_usize_with_underscores() {
+    assert_eq!("0", usize_with_underscores(0));
+    assert_eq!("1", usize_with_underscores(1));
+    assert_eq!("99", usize_with_underscores(99));
+    assert_eq!("345", usize_with_underscores(345));
+    assert_eq!("1_000", usize_with_underscores(1_000));
+    assert_eq!("12_001", usize_with_underscores(12_001));
+    assert_eq!("999_999", usize_with_underscores(999_999));
+    assert_eq!("1_000_000", usize_with_underscores(1_000_000));
+    assert_eq!("12_345_678", usize_with_underscores(12_345_678));
+}
+
+#[test]
+fn test_isize_with_underscores() {
+    assert_eq!("0", isize_with_underscores(0));
+    assert_eq!("-1", isize_with_underscores(-1));
+    assert_eq!("99", isize_with_underscores(99));
+    assert_eq!("345", isize_with_underscores(345));
+    assert_eq!("-1_000", isize_with_underscores(-1_000));
+    assert_eq!("12_001", isize_with_underscores(12_001));
+    assert_eq!("-999_999", isize_with_underscores(-999_999));
+    assert_eq!("1_000_000", isize_with_underscores(1_000_000));
+    assert_eq!("-12_345_678", isize_with_underscores(-12_345_678));
+}
+
+#[test]
+fn test_f64p1_with_underscores() {
+    assert_eq!("0.0", f64p1_with_underscores(0f64));
+    assert_eq!("0.0", f64p1_with_underscores(0.00000001));
+    assert_eq!("-0.0", f64p1_with_underscores(-0.00000001));
+    assert_eq!("1.0", f64p1_with_underscores(0.9999999));
+    assert_eq!("-1.0", f64p1_with_underscores(-0.9999999));
+    assert_eq!("345.5", f64p1_with_underscores(345.4999999));
+    assert_eq!("-100_000.0", f64p1_with_underscores(-100_000f64));
+    assert_eq!("123_456_789.1", f64p1_with_underscores(123456789.123456789));
+    assert_eq!("-123_456_789.1", f64p1_with_underscores(-123456789.123456789));
 }
diff --git a/compiler/rustc_data_structures/src/vec_cache.rs b/compiler/rustc_data_structures/src/vec_cache.rs
index 2ff60ab7f36..3b448c056b7 100644
--- a/compiler/rustc_data_structures/src/vec_cache.rs
+++ b/compiler/rustc_data_structures/src/vec_cache.rs
@@ -68,22 +68,22 @@ impl SlotIndex {
     // slots (see `slot_index_exhaustive` in tests).
     #[inline]
     const fn from_index(idx: u32) -> Self {
-        let mut bucket = match idx.checked_ilog2() {
-            Some(x) => x as usize,
-            None => 0,
-        };
-        let entries;
-        let running_sum;
-        if bucket <= 11 {
-            entries = 1 << 12;
-            running_sum = 0;
-            bucket = 0;
-        } else {
-            entries = 1 << bucket;
-            running_sum = entries;
-            bucket = bucket - 11;
+        const FIRST_BUCKET_SHIFT: usize = 12;
+        if idx < (1 << FIRST_BUCKET_SHIFT) {
+            return SlotIndex {
+                bucket_idx: 0,
+                entries: 1 << FIRST_BUCKET_SHIFT,
+                index_in_bucket: idx as usize,
+            };
+        }
+        // SAFETY: We already ruled out idx 0, so `checked_ilog2` can't return `None`.
+        let bucket = unsafe { idx.checked_ilog2().unwrap_unchecked() as usize };
+        let entries = 1 << bucket;
+        SlotIndex {
+            bucket_idx: bucket - FIRST_BUCKET_SHIFT + 1,
+            entries,
+            index_in_bucket: idx as usize - entries,
         }
-        SlotIndex { bucket_idx: bucket, entries, index_in_bucket: idx as usize - running_sum }
     }
 
     // SAFETY: Buckets must be managed solely by functions here (i.e., get/put on SlotIndex) and
diff --git a/compiler/rustc_data_structures/src/vec_cache/tests.rs b/compiler/rustc_data_structures/src/vec_cache/tests.rs
index 3b65c14162e..9b60913ec92 100644
--- a/compiler/rustc_data_structures/src/vec_cache/tests.rs
+++ b/compiler/rustc_data_structures/src/vec_cache/tests.rs
@@ -75,24 +75,21 @@ fn slot_index_exhaustive() {
     for idx in 0..=u32::MAX {
         buckets[SlotIndex::from_index(idx).bucket_idx] += 1;
     }
-    let mut prev = None::<SlotIndex>;
-    for idx in 0..=u32::MAX {
+    let slot_idx = SlotIndex::from_index(0);
+    assert_eq!(slot_idx.index_in_bucket, 0);
+    assert_eq!(slot_idx.bucket_idx, 0);
+    let mut prev = slot_idx;
+    for idx in 1..=u32::MAX {
         let slot_idx = SlotIndex::from_index(idx);
-        if let Some(p) = prev {
-            if p.bucket_idx == slot_idx.bucket_idx {
-                assert_eq!(p.index_in_bucket + 1, slot_idx.index_in_bucket);
-            } else {
-                assert_eq!(slot_idx.index_in_bucket, 0);
-            }
+        if prev.bucket_idx == slot_idx.bucket_idx {
+            assert_eq!(prev.index_in_bucket + 1, slot_idx.index_in_bucket);
         } else {
-            assert_eq!(idx, 0);
             assert_eq!(slot_idx.index_in_bucket, 0);
-            assert_eq!(slot_idx.bucket_idx, 0);
         }
 
         assert_eq!(buckets[slot_idx.bucket_idx], slot_idx.entries as u32);
         assert_eq!(ENTRIES_BY_BUCKET[slot_idx.bucket_idx], slot_idx.entries, "{}", idx);
 
-        prev = Some(slot_idx);
+        prev = slot_idx;
     }
 }