Implements the following simplifications:
(a - b) + b => a
(a * b) + (a * c) => a * (b + c)
Also adds logic to simplification to handle rules that create new operations
that might need simplification, such as the second rule above.
Only perform the second simplification if the multiplies have the add as their
only use. Otherwise this is a deoptimization of size and performance.
Currently it is impossible to invalidate the constnat and type manager.
However, the compact ids pass changes the ids for the types and
constants, which makes them invalid. This change will make them
analyses that have to been explicitly marked as preserved by passes.
This will allow compact ids to invalidate them.
Fixes#2220.
Currently the IRContext is passed into the Pass::Process method. It is
then up to the individual pass to store the context into the context_
variable. This CL changes the Run method to store the context before
calling Process which no-longer receives the context as a parameter.
This CL moves the files in opt/ to consistenly be under the opt::
namespace. This frees up the ir:: namespace so it can be used to make a
shared ir represenation.
Fixes a bug at the same time. In `UpdateDefUse`, if the definition
already exists, we are not suppose to analyse it again. When you do
the entries for the definition are deleted, and we don't want that.
The check for this was wrong.
Building the def-use chains is very expensive, so we do not want to
invalidate them it if is not necessary. At the moment, it seems like
most optimizatoins are good at not invalidating the def-use chains, but
simplification does.
This PR get the simlification pass to keep the analysies valid.
Contributes to #1328.
Implementation of the simplification pass.
- Create pass that calls the instruction folder on each instruction and
propagate instructions that fold to a copy. This will do copy
propagation as well.
- Did not use the propagator engine because I want to modify the instruction
as we go along.
- Change folding to not allocate new instructions, but make changes in
place. This change had a big impact on compile time.
- Add simplification pass to the legalization passes in place of
insert-extract elimination.
- Added test cases for new folding rules.
- Added tests for the simplification pass
- Added a method to the CFG to apply a function to the basic blocks in
reverse post order.
Contributes to #1164.
