doc/go1.19: Linux race detector now requires glibc 2.17

Fixes golang#53522

Change-Id: Ibed838d358a733d26a6c3d89446d7fadb1012961
Reviewed-on: https://go-review.googlesource.com/c/go/+/413876
Reviewed-by: Keith Randall <[email protected]>
Reviewed-by: Keith Randall <[email protected]>
Reviewed-by: Ian Lance Taylor <[email protected]>
Run-TryBot: Ian Lance Taylor <[email protected]>
Auto-Submit: Ian Lance Taylor <[email protected]>
Run-TryBot: Ian Lance Taylor <[email protected]>
TryBot-Result: Gopher Robot <[email protected]>

Author: ianlancetaylor

doc/go1.19.html

@@ -807,6 +807,7 @@ <h3 id="minor_library_changes">Minor changes to the library</h3>
       Compared to v2, it is now typically 1.5x to 2x faster, uses half
       as much memory, and it supports an unlimited number of
       goroutines.
+      On Linux, the race detector now requires at least glibc version 2.17.
     </p>
 
     <p><!-- CL 336549 -->

src/math/hypot_arm64.s

@@ -0,0 +1,55 @@
+// Copyright 2021 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+#include "textflag.h"
+
+#define PosInf 0x7FF0000000000000
+#define NaN 0x7FF8000000000001
+
+// func archHypot(p, q float64) float64
+TEXT ·archHypot(SB), NOSPLIT, $0-24
+	FMOVD	p+0(FP), F0
+	FMOVD	q+8(FP), F1
+	MOVD	$PosInf, R0
+	FMOVD	R0, F30 // F30 is PosInf
+
+	FABSD	F0, F0
+	FABSD	F1, F1
+	FCMPD	F30, F0
+	BGE	isInf
+	FCMPD	F30, F1
+	BGE	isInf
+
+	FCMPED	F0, F0
+	BNE	isNaN
+	FCMPED	F1, F1
+	BNE	isNaN
+
+	FMAXD	F0, F1, F2 // p is greater
+	FMIND	F0, F1, F3 // q is less
+	FCMPD	F2, 0.0
+	BEQ	IsZero // if p == 0, return 0
+
+	//      p   q
+	FDIVD	F2, F3, F3
+	FMULD 	F3, F3, F3
+	FMOVD	$1.0, F4
+	FADDD	F4, F3, F3
+	FSQRTD	F3, F3
+	FMULD	F3, F2, F3
+	FMOVD	F3, ret+16(FP)
+	RET
+
+isNaN:
+	MOVD	$NaN, R0
+	FMOVD	R0, F29 // F29 is NaN
+	FMOVD    F29, ret+16(FP) // return NaN
+	RET
+isInf:
+	FMOVD    F30, ret+16(FP) // return +Inf
+	RET
+isZero:
+	// R0 has been set to zero
+	MOVD    R0, ret+16(FP) // return 0
+	RET

src/math/hypot_asm.go

@@ -2,7 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build 386 || amd64
+//go:build 386 || amd64 || arm64
+// +build 386 amd64 arm64
 
 package math
 

src/math/hypot_noasm.go

@@ -2,7 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build !386 && !amd64
+//go:build !386 && !amd64 && !arm64
+// +build !386,!amd64,!arm64
 
 package math