Alan Donovan 142566e529 go/ssa: avoid "premature optimization" of dead branch removal.
Blocks dominated by "if false" should be retained in the
initial SSA form so they remain visible to subsequent source
code analysis tools.

In any case, true compilers already need a stronger version of
this optimization so they can simplify CFGs such as this:
	const x, y = ...
        switch x {case y:...}
where a branch is constant but the comparison of constants
does not occur within an expression.

LGTM=gri
R=gri
CC=golang-codereviews, pcc
https://golang.org/cl/101250043
2014-06-12 11:31:41 -04:00
..