code review 63720043: cmd/gc: correct liveness for various non-returning functions

cmd/gc: correct liveness for various non-returning functions

When the liveness code doesn't know a function doesn't return
(but the generated code understands that), the liveness analysis
invents a control flow edge that is not really there, which can cause
variables to seem spuriously live. This is particularly bad when the
variables are uninitialized.

[rsc, 2014-02-14 05:38:19]

Hello iant (cc: golang-codereviews@googlegroups.com),

I'd like you to review this change to
https://code.google.com/p/go/

[rsc, 2014-02-14 05:38:24]

*** Submitted as https://code.google.com/p/go/source/detail?r=b0a8d13410a6 ***

cmd/gc: correct liveness for various non-returning functions

When the liveness code doesn't know a function doesn't return
(but the generated code understands that), the liveness analysis
invents a control flow edge that is not really there, which can cause
variables to seem spuriously live. This is particularly bad when the
variables are uninitialized.

TBR=iant
CC=golang-codereviews
https://codereview.appspot.com/63720043

[gobot, 2014-02-14 07:18:21]

This CL appears to have broken the plan9-386-cnielsen builder.

[iant, 2014-02-14 15:36:15]

LGTM