Add Go frontend, libgo library, and Go testsuite.

gcc/:
	* gcc.c (default_compilers): Add entry for ".go".
	* common.opt: Add -static-libgo as a driver option.
	* doc/install.texi (Configuration): Mention libgo as an option for
	--enable-shared.  Mention go as an option for --enable-languages.
	* doc/invoke.texi (Overall Options): Mention .go as a file name
	suffix.  Mention go as a -x option.
	* doc/frontends.texi (G++ and GCC): Mention Go as a supported
	language.
	* doc/sourcebuild.texi (Top Level): Mention libgo.
	* doc/standards.texi (Standards): Add section on Go language.
	Move references for other languages into their own section.
	* doc/contrib.texi (Contributors): Mention that I contributed the
	Go frontend.
gcc/testsuite/:
	* lib/go.exp: New file.
	* lib/go-dg.exp: New file.
	* lib/go-torture.exp: New file.
	* lib/target-supports.exp (check_compile): Match // Go.

From-SVN: r167407

1 files changed, 79 insertions, 0 deletions

diff --git a/libgo/go/math/atanh.go b/libgo/go/math/atanh.go
new file mode 100644
index 0000000..6aecb7b
--- /dev/null
+++ b/libgo/go/math/atanh.go
@@ -0,0 +1,79 @@
+// Copyright 2010 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.
+
+package math
+
+
+// The original C code, the long comment, and the constants
+// below are from FreeBSD's /usr/src/lib/msun/src/e_atanh.c
+// and came with this notice.  The go code is a simplified
+// version of the original C.
+//
+// ====================================================
+// Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
+//
+// Developed at SunPro, a Sun Microsystems, Inc. business.
+// Permission to use, copy, modify, and distribute this
+// software is freely granted, provided that this notice
+// is preserved.
+// ====================================================
+//
+//
+// __ieee754_atanh(x)
+// Method :
+//	1. Reduce x to positive by atanh(-x) = -atanh(x)
+//	2. For x>=0.5
+//	            1              2x                          x
+//	atanh(x) = --- * log(1 + -------) = 0.5 * log1p(2 * --------)
+//	            2             1 - x                      1 - x
+//
+//	For x<0.5
+//	atanh(x) = 0.5*log1p(2x+2x*x/(1-x))
+//
+// Special cases:
+//	atanh(x) is NaN if |x| > 1 with signal;
+//	atanh(NaN) is that NaN with no signal;
+//	atanh(+-1) is +-INF with signal.
+//
+
+// Atanh(x) calculates the inverse hyperbolic tangent of x.
+//
+// Special cases are:
+//	Atanh(x) = NaN if x < -1 or x > 1
+//	Atanh(1) = +Inf
+//	Atanh(-1) = -Inf
+//	Atanh(NaN) = NaN
+func Atanh(x float64) float64 {
+	const NearZero = 1.0 / (1 << 28) // 2**-28
+	// TODO(rsc): Remove manual inlining of IsNaN
+	// when compiler does it for us
+	// special cases
+	switch {
+	case x < -1 || x > 1 || x != x: // x < -1 || x > 1 || IsNaN(x):
+		return NaN()
+	case x == 1:
+		return Inf(1)
+	case x == -1:
+		return Inf(-1)
+	}
+	sign := false
+	if x < 0 {
+		x = -x
+		sign = true
+	}
+	var temp float64
+	switch {
+	case x < NearZero:
+		temp = x
+	case x < 0.5:
+		temp = x + x
+		temp = 0.5 * Log1p(temp+temp*x/(1-x))
+	default:
+		temp = 0.5 * Log1p((x+x)/(1-x))
+	}
+	if sign {
+		temp = -temp
+	}
+	return temp
+}