From: Russ Cox <rsc@golang.org>
Date: Mon, 6 Feb 2012 16:24:34 +0000 (-0500)
Subject: runtime: fix float64 hash on 32-bit machine
X-Git-Tag: weekly.2012-02-07~41
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=facee93a8627881ae39abda13cba115274fe20cf;p=gostls13.git

runtime: fix float64 hash on 32-bit machine

Multiplying by the low 32 bits was a bad idea
no matter what, but it was a particularly unfortunate
choice because those bits are 0 for small integer values.

Fixes #2883.

R=ken2
CC=golang-dev
https://golang.org/cl/5634047
---

diff --git a/src/pkg/runtime/alg.c b/src/pkg/runtime/alg.c
index eec523aad4..e3c42916e9 100644
--- a/src/pkg/runtime/alg.c
+++ b/src/pkg/runtime/alg.c
@@ -271,7 +271,7 @@ runtime·f64hash(uintptr *h, uintptr s, void *a)
 	else {
 		u = *(uint64*)a;
 		if(sizeof(uintptr) == 4)
-			hash = ((uint32)(u>>32) ^ 2860486313) * (uint32)u;
+			hash = ((uint32)(u>>32) * 3267000013UL) ^ (uint32)u;
 		else
 			hash = u;
 	}