[llvm-dev] Request suggestions about how to remove redundencies caused by SCEV expansion fundementally

[Sanjoy Das via llvm-dev]

Hi Wei,

I've not seen GCC's SCEV so I cannot make a comparative comment here
(maybe Chris, Andy or Dan can chime in here), but I personally am in
the "make the cleanup passes smarter" camp.  We can also try to make
SCEV expansion smarter -- not by putting more things in SCEVExpander
(it is already complex enough!), but by splitting out a dedicated
SCEVSimplifier that you invoke on code generated from SCEVExpander to
strength reduce it.  SCEVSimplifier can then internally use routines
in SCEV, so that it is "as smart as" SCEV in most cases.

-- Sanjoy