Commit Graph

2 Commits

Author SHA1 Message Date
Daniel Berlin eafdd862e5 NewGVN: Fix PR/33187. This is a bug caused by two things:
1. When there is no perfect iteration order, we can't let phi nodes
put themselves in terms of things that come later in the iteration
order, or we will endlessly cycle (the normal RPO algorithm clears the
hashtable to avoid this issue).
2. We are sometimes erasing the wrong expression (causing pessimism)
because our equality says loads and stores are the same.
We introduce an exact equality function and use it when erasing to
make sure we erase only identical expressions, not equivalent ones.

llvm-svn: 304807
2017-06-06 17:15:28 +00:00
Davide Italiano 9a0f542db6 [NewGVN] Create a StoreExpression instead of a VariableExpression.
In the case where we have an operand defined by a lod of the
same memory location. Historically this was a VariableExpression
because we wanted to make sure they ended up in the same class,
but if we create the right expression, they end up in the same
class anyway.

Fixes PR32897. Thanks to Dan for the detailed discussion and the
fix suggestion.

llvm-svn: 303475
2017-05-20 00:46:54 +00:00