From: Ilya Tocar <ilya.tocar@intel.com>
Date: Wed, 14 Sep 2016 12:23:41 +0000 (+0300)
Subject: math: make sqrt smaller on AMD64
X-Git-Tag: go1.8beta1~1118
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=731b3ed18dcb854912cb06b3486bb633917e4cb7;p=gostls13.git

math: make sqrt smaller on AMD64

This makes function fit in 16 bytes, saving 16 bytes.

Change-Id: Iac5d2add42f6dae985b2a5cbe19ad4bd4bcc92ec
Reviewed-on: https://go-review.googlesource.com/29151
Run-TryBot: Ilya Tocar <ilya.tocar@intel.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
---

diff --git a/src/math/sqrt_amd64.s b/src/math/sqrt_amd64.s
index d72000fccb..1102903055 100644
--- a/src/math/sqrt_amd64.s
+++ b/src/math/sqrt_amd64.s
@@ -6,7 +6,7 @@
 
 // func Sqrt(x float64) float64
 TEXT ·Sqrt(SB), NOSPLIT, $0
-	MOVSD  x+0(FP), X0
-	SQRTSD X0, X1
-	MOVSD  X1, ret+8(FP)
+	XORPS  X0, X0 // break dependency
+	SQRTSD x+0(FP), X0
+	MOVSD  X0, ret+8(FP)
 	RET