build: compilation considerably slower compared to 1.4

[awly]

Compilation times even for trivial programs have regressed quite noticeably since 1.4
Example:

$ go version
go version devel +2d9a50b Fri May 8 19:10:10 2015 +0000 darwin/amd64

$ ~/.go1.4/bin/go version
go version go1.4.1 darwin/amd64

$ time go build -v -x
WORK=/var/folders/vg/njvw3b2118z775q_7hp6c_1h0000gn/T/go-build986103443
github.com/alytvynov/notify
mkdir -p $WORK/github.com/alytvynov/notify/_obj/
mkdir -p $WORK/github.com/alytvynov/notify/_obj/exe/
cd /Users/cronos/go/src/github.com/alytvynov/notify
/Users/cronos/.go/pkg/tool/darwin_amd64/6g -o $WORK/github.com/alytvynov/notify.a -trimpath $WORK -p main -complete -D _/Users/cronos/go/src/github.com/alytvynov/notify -I $WORK -pack ./notify.go
cd .
/Users/cronos/.go/pkg/tool/darwin_amd64/6l -o $WORK/github.com/alytvynov/notify/_obj/exe/a.out -L $WORK -extld=clang -buildmode=exe $WORK/github.com/alytvynov/notify.a
mv $WORK/github.com/alytvynov/notify/_obj/exe/a.out notify

real    0m0.703s
user    0m0.587s
sys 0m0.103s

$ time GOROOT=~/.go1.4 ~/.go1.4/bin/go build -v -x
WORK=/var/folders/vg/njvw3b2118z775q_7hp6c_1h0000gn/T/go-build023012609
github.com/alytvynov/notify
mkdir -p $WORK/github.com/alytvynov/notify/_obj/
mkdir -p $WORK/github.com/alytvynov/notify/_obj/exe/
cd /Users/cronos/go/src/github.com/alytvynov/notify
/Users/cronos/.go1.4/pkg/tool/darwin_amd64/6g -o $WORK/github.com/alytvynov/notify.a -trimpath $WORK -p github.com/alytvynov/notify -complete -D _/Users/cronos/go/src/github.com/alytvynov/notify -I $WORK -pack ./notify.go
cd .
/Users/cronos/.go1.4/pkg/tool/darwin_amd64/6l -o $WORK/github.com/alytvynov/notify/_obj/exe/a.out -L $WORK -extld=clang $WORK/github.com/alytvynov/notify.a
mv $WORK/github.com/alytvynov/notify/_obj/exe/a.out notify

real    0m0.230s
user    0m0.173s
sys 0m0.043s

This is 0.7s on tip vs 0.23s on 1.4.

For other larger project (which is unfortunately not open-source) i get 2.57s vs 0.9s

This might be related to compiler translation to Go.

[minux]

Yes, it's known issue, and indeed related to the Go translation.

[robpike]

This is really #10571. Closing. Let's not have multiple bugs tracking the work.

[anacrolix]

I think #10571 is only a symptom of this.