libgo: update to Go1.12beta2

    
    Reviewed-on: https://go-review.googlesource.com/c/158019

gotools/:
	* Makefile.am (go_cmd_vet_files): Update for Go1.12beta2 release.
	(GOTOOLS_TEST_TIMEOUT): Increase to 600.
	(check-runtime): Export LD_LIBRARY_PATH before computing GOARCH
	and GOOS.
	(check-vet): Copy golang.org/x/tools into check-vet-dir.
	* Makefile.in: Regenerate.

gcc/testsuite/:
	* go.go-torture/execute/names-1.go: Stop using debug/xcoff, which
	is no longer externally visible.

From-SVN: r268084

1 files changed, 14 insertions, 6 deletions

diff --git a/libgo/go/math/unsafe.go b/libgo/go/math/unsafe.go
index 5ae6742..e59f50c 100644
--- a/libgo/go/math/unsafe.go
+++ b/libgo/go/math/unsafe.go
@@ -6,16 +6,24 @@ package math
 
 import "unsafe"
 
-// Float32bits returns the IEEE 754 binary representation of f.
+// Float32bits returns the IEEE 754 binary representation of f,
+// with the sign bit of f and the result in the same bit position.
+// Float32bits(Float32frombits(x)) == x.
 func Float32bits(f float32) uint32 { return *(*uint32)(unsafe.Pointer(&f)) }
 
-// Float32frombits returns the floating point number corresponding
-// to the IEEE 754 binary representation b.
+// Float32frombits returns the floating-point number corresponding
+// to the IEEE 754 binary representation b, with the sign bit of b
+// and the result in the same bit position.
+// Float32frombits(Float32bits(x)) == x.
 func Float32frombits(b uint32) float32 { return *(*float32)(unsafe.Pointer(&b)) }
 
-// Float64bits returns the IEEE 754 binary representation of f.
+// Float64bits returns the IEEE 754 binary representation of f,
+// with the sign bit of f and the result in the same bit position,
+// and Float64bits(Float64frombits(x)) == x.
 func Float64bits(f float64) uint64 { return *(*uint64)(unsafe.Pointer(&f)) }
 
-// Float64frombits returns the floating point number corresponding
-// the IEEE 754 binary representation b.
+// Float64frombits returns the floating-point number corresponding
+// to the IEEE 754 binary representation b, with the sign bit of b
+// and the result in the same bit position.
+// Float64frombits(Float64bits(x)) == x.
 func Float64frombits(b uint64) float64 { return *(*float64)(unsafe.Pointer(&b)) }