LSRUse's Regs set after all pruning is done, rather than trying
to do it on the fly, which can produce an incomplete result.
This fixes a case where heuristic pruning was stripping all
formulae from a use, which led the solver to enter an infinite
loop.
Also, add a few asserts to diagnose this kind of situation.
llvm-svn: 103328
doesn't dominate the header is needed, don't check whether the increment
expression has computable loop evolution. While the operands of an
addrec are required to be loop-invariant, they're not required to
dominate any part of the loop. This fixes PR6914.
llvm-svn: 102389
Dan Gohman