1 files changed, 35 insertions, 0 deletions
diff --git a/test/fixedbugs/issue7740.go b/test/fixedbugs/issue7740.go
new file mode 100644
index 0000000..6bc6249
--- /dev/null
+++ b/test/fixedbugs/issue7740.go
@@ -0,0 +1,35 @@
+// run
+
+// Copyright 2015 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.
+
+// This test computes the precision of the compiler's internal multiprecision floats.
+
+package main
+
+import (
+	"fmt"
+	"math"
+	"runtime"
+)
+
+const ulp = (1.0 + (2.0 / 3.0)) - (5.0 / 3.0)
+
+func main() {
+	// adjust precision depending on compiler
+	var prec float64
+	switch runtime.Compiler {
+	case "gc":
+		prec = math.Inf(1) // exact precision using rational arithmetic
+	case "gccgo":
+		prec = 256
+	default:
+		// unknown compiler
+		return
+	}
+	p := 1 - math.Log(math.Abs(ulp))/math.Log(2)
+	if math.Abs(p-prec) > 1e-10 {
+		fmt.Printf("BUG: got %g; want %g\n", p, prec)
+	}
+}