From d27be66ec5acf0ae5eeef8ee8c0bb4de66f96257 Mon Sep 17 00:00:00 2001
From: Stefan Karpinski <stefan@karpinski.org>
Date: Tue, 2 Jun 2020 13:50:49 -0400
Subject: [PATCH] hash_uint: simplify definitions

---
 base/char.jl    |  2 +-
 base/float.jl   |  2 +-
 base/hashing.jl | 45 +++++----------------------------------------
 3 files changed, 7 insertions(+), 42 deletions(-)

diff --git a/base/char.jl b/base/char.jl
index 173c84711e551..86c2b712894b7 100644
--- a/base/char.jl
+++ b/base/char.jl
@@ -208,7 +208,7 @@ in(x::AbstractChar, y::AbstractChar) = x == y
 ==(x::Char, y::Char) = reinterpret(UInt32, x) == reinterpret(UInt32, y)
 isless(x::Char, y::Char) = reinterpret(UInt32, x) < reinterpret(UInt32, y)
 hash(x::Char, h::UInt) =
-    hash_uint64(((reinterpret(UInt32, x) + UInt64(0xd4d64234)) << 32) ⊻ UInt64(h))
+    hash_uint(((reinterpret(UInt32, x) + UInt64(0xd4d64234)) << 32) ⊻ UInt64(h))
 
 first_utf8_byte(c::Char) = (reinterpret(UInt32, c) >> 24) % UInt8
 
diff --git a/base/float.jl b/base/float.jl
index 42b298ebec595..f800bcc319da3 100644
--- a/base/float.jl
+++ b/base/float.jl
@@ -565,7 +565,7 @@ isinf(x::Real) = !isnan(x) & !isfinite(x)
 
 ## hashing small, built-in numeric types ##
 
-hx(a::UInt64, b::Float64, h::UInt) = hash_uint64((3a + reinterpret(UInt64,b)) - h)
+hx(a::UInt64, b::Float64, h::UInt) = hash_uint((3a + reinterpret(UInt64,b)) - h)
 const hx_NaN = hx(UInt64(0), NaN, UInt(0  ))
 
 hash(x::UInt64,  h::UInt) = hx(x, Float64(x), h)
diff --git a/base/hashing.jl b/base/hashing.jl
index 7b962a58ad5ad..7918ffb732fe0 100644
--- a/base/hashing.jl
+++ b/base/hashing.jl
@@ -24,46 +24,11 @@ hash(@nospecialize(x), h::UInt) = hash_uint(3h - objectid(x))
 
 ## core data hashing functions ##
 
-function hash_64_64(n::UInt64)
-    a::UInt64 = n
-    a = ~a + a << 21
-    a =  a ⊻ a >> 24
-    a =  a + a << 3 + a << 8
-    a =  a ⊻ a >> 14
-    a =  a + a << 2 + a << 4
-    a =  a ⊻ a >> 28
-    a =  a + a << 31
-    return a
-end
-
-function hash_64_32(n::UInt64)
-    a::UInt64 = n
-    a = ~a + a << 18
-    a =  a ⊻ a >> 31
-    a =  a * 21
-    a =  a ⊻ a >> 11
-    a =  a + a << 6
-    a =  a ⊻ a >> 22
-    return a % UInt32
-end
-
-function hash_32_32(n::UInt32)
-    a::UInt32 = n
-    a = a + 0x7ed55d16 + a << 12
-    a = a ⊻ 0xc761c23c ⊻ a >> 19
-    a = a + 0x165667b1 + a << 5
-    a = a + 0xd3a2646c ⊻ a << 9
-    a = a + 0xfd7046c5 + a << 3
-    a = a ⊻ 0xb55a4f09 ⊻ a >> 16
-    return a
-end
-
-if UInt === UInt64
-    hash_uint64(x::UInt64) = hash_64_64(x)
-    hash_uint(x::UInt)     = hash_64_64(x)
-else
-    hash_uint64(x::UInt64) = hash_64_32(x)
-    hash_uint(x::UInt)     = hash_32_32(x)
+function hash_uint(n::T) where {T <: Union{UInt64, UInt32}}
+    # random constants, last must be odd
+    n += 0xe391e8b4ff155ee5 % T
+    n ⊻= 0xb9d8ebf206d49927 % T
+    n *= 0xafa64689f53d9ee1 % T
 end
 
 ## symbol & expression hashing ##