Chris Lattner 371f542759 Fix a problem that Dan Berlin noticed, where reassociation would not succeed
in building maximal expressions before simplifying them.  In particular, i
cases like this:

X-(A+B+X)

the code would consider A+B+X to be a maximal expression (not understanding
that the single use '-' would be turned into a + later), simplify it (a noop)
then later get simplified again.

Each of these simplify steps is where the cost of reassociation comes from,
so this patch should speed up the already fast pass a bit.

Thanks to Dan for noticing this!

llvm-svn: 23214
2005-09-02 07:07:58 +00:00
..
2005-04-21 23:48:37 +00:00