+Go 1.8 is not yet released. These are work-in-progress +release notes. Go 1.8 is expected to be released in February 2017. +
+ ++The latest Go release, version 1.8, arrives six months after Go 1.7. +Most of its changes are in the implementation of the toolchain, runtime, and libraries. +There is one minor change to the language specification. +As always, the release maintains the Go 1 promise of compatibility. +We expect almost all Go programs to continue to compile and run as before. +
+ ++The release adds support for 32-bit MIPS, +updates the compiler back end to generate more efficient code, +produces smaller binaries (TODO: link/numbers), +reduces GC pauses by eliminating stop-the-world stack rescanning, +adds HTTP/2 Push support, +adds HTTP graceful shutdown, +and simplifies sorting slices. +
+ ++When explicitly converting structs, tags are now ignored for structural type identity. +See change 24190 for details. +
+ +
+Go now supports 32-bit MIPS on Linux for both big-endian
+(linux/mips) and little-endian machines
+(linux/mipsle).
+
+Go now requires DragonFly BSD 4.4.4 or later. +
+ ++The Plan 9 port's networking support is now much more complete +and matches the behavior of Unix and Windows with respect to deadlines +and cancelation. +
+ + ++There are some instabilities on FreeBSD that are known but not understood. +These can lead to program crashes in rare cases. +See +issue 15658 +and issue 16396. +Any help in solving these FreeBSD-specific issues would be appreciated. +
+ +
+For 64-bit x86 systems, the following instructions have been added:
+VBROADCASTSD,
+BROADCASTSS,
+MOVDDUP,
+MOVSHDUP,
+MOVSLDUP,
+VMOVDDUP,
+VMOVSHDUP,
+and VMOVSLDUP.
+For 64-bit PPC systems, the common vector scalar instructions have been +added. See change 30510. +
+ +
+The yacc (previously available via
+“go tool yacc”)
+has been removed. As of Go 1.7 it was no longer used by the Go compiler.
+It has moved to the “tools” repo and is and is available via
+go get golang.org/x/tools/cmd/goyacc.
+
+Go 1.7 introduced a new compiler back end for 64-bit x86 systems. +In Go 1.8, that back end has been developed further and is now used for +all architectures. +
+ ++The new back end, based on +SSA, +generates more compact, more efficient code +and provides a better platform for optimizations +such as bounds check elimination. +The new back end reduces the CPU time required by +our benchmark programs by N-M%. +TODO: ARM binary size & perf numbers. +
+ +
+The temporary -ssa=0 flag introduced in Go 1.7 to disable
+the new backend has been removed in Go 1.8.
+
+The compiler and linker have been optimized and run faster in this +release than in Go 1.7, although they are still slower than we would +like and will continue to be optimized in future releases. +
+ ++Due to changes across the compiler toolchain and standard library, +binaries built with this release should typically be smaller than binaries +built with Go 1.7, sometimes by as much as TODO numbers. +
+ + +TODO
+ +TODO
+ +
+The go command's basic operation
+is unchanged, but there are a number of changes worth noting.
+
+A new “go bug” command helps users file bug reports.
+
+As always, the changes are so general and varied that precise statements +about performance are difficult to make. +Most programs should run a bit faster, +due to speedups in the garbage collector and +optimizations in the core library. +
+ +
+There have been significant optimizations bringing more than 10% improvements
+to implementations in the
+TODO TODO:
+foo,
+bar,
+and
+quux
+packages.
+
+Garbage collection pauses should be significantly shorter than they +were in Go 1.7, often as low as 10 microseconds and usually under 100 +microseconds. +See the + +document on eliminating stop-the-world stack re-scanning for details. +More work remains for Go 1.9. +
+ +defer calls are now about twice as fast.
Calls from Go into C are now TODO% faster.
+ ++Many examples have been added to the documentation across many packages. +
+ +
+The sort package
+now includes a convenience function
+sort.Slice to sort a
+slice given a less function.
+
+In many cases this means that writing a new sorter type is not
+necessary.
+
+Also new are
+sort.SliceStable and
+sort.SliceIsSorted.
+
+The net/http package now includes a
+mechanism to
+send HTTP/2 server pushes from a
+Handler.
+Similar to the existing Flusher and Hijacker
+interfaces, an HTTP/2
+ResponseWriter
+now implements the new
+Pusher interface.
+
+As always, there are various minor changes and updates to the library, +made with the Go 1 promise of compatibility +in mind. +
+ ++
++
+