Adding upstream version 86.0.1.upstream/86.0.1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

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diff --git a/third_party/rust/rustc-hash/README.md b/third_party/rust/rustc-hash/README.md
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+# rustc-hash
+
+A speedy hash algorithm used within rustc. The hashmap in liballoc by
+default uses SipHash which isn't quite as speedy as we want. In the
+compiler we're not really worried about DOS attempts, so we use a fast
+non-cryptographic hash.
+
+This is the same as the algorithm used by Firefox -- which is a
+homespun one not based on any widely-known algorithm -- though
+modified to produce 64-bit hash values instead of 32-bit hash
+values. It consistently out-performs an FNV-based hash within rustc
+itself -- the collision rate is similar or slightly worse than FNV,
+but the speed of the hash function itself is much higher because it
+works on up to 8 bytes at a time.
+
+## Usage
+
+```
+use rustc_hash::FxHashMap;
+let map: FxHashMap<u32, u32> = FxHashMap::default();
+```