Module optimize

A collection of optimization passes.

Each of these modules are a collection of typical code optimisation passes.

Currently there is no pass manager, as there are only a couple of passes, but this is something which will be added in the future.

So each of the functions under this module will return a boolean indicating whether a modification to the IR was made. Typically the passes will be just re-run until they no longer make any such modifications, implying they’ve optimized as much possible.

When writing passes one should keep in mind that when a modification is made then any iterators over blocks or instructions can be invalidated, and starting over is a safer option than trying to attempt multiple changes at once.

Re-exports

• pub use arg_demotion::*;
• pub use const_demotion::*;
• pub use constants::*;
• pub use conditional_constprop::*;
• pub use cse::*;
• pub use dce::*;
• pub use inline::*;
• pub use mem2reg::*;
• pub use memcpyopt::*;
• pub use misc_demotion::*;
• pub use ret_demotion::*;
• pub use simplify_cfg::*;
• pub use sroa::*;
• pub use fn_dedup::*;

Modules

• arg_demotion
• conditional_constprop
  When a value is guaranteed to have a constant value in a region of the CFG, this optimization replaces uses of that value with the constant in that region.
• const_demotion
• constants
  Optimization passes for manipulating constant values.
• cse
  Value numbering based common subexpression elimination. Reference: Value Driven Redundancy Elimination - Loren Taylor Simpson.
• dce
  Dead Code Elimination
• fn_dedup
  Deduplicate functions.
• inline
  Function inlining.
• mem2reg
• memcpyopt
  Optimisations related to mem_copy.
• misc_demotion
• ret_demotion
• simplify_cfg
  Simplify Control Flow Graph
• sroa
  Scalar Replacement of Aggregates