THURSDAY, AUGUST 20, 2026
gcc Performance Win
Improve infer::clear performance
Optimizes range inference clear operations by using a linked list.
The performance of range inference clear operations has been improved by replacing a full control flow graph walk with a traversal of a linked list. This optimization focuses the clearing process on relevant data structures, reducing overhead and speeding up the range analysis phase of the compiler, addressing PR tree-optimization/126856.
In Details
The infer_range_manager::clear method in gimple-range-infer.cc is optimized by changing its traversal strategy from a full CFG walk to a linked list walk using ssa_name_link. This change targets only the necessary nodes for range clearing, significantly improving performance for range analysis, as per PR tree-optimization/126856.
For Context
- range inference
- A compiler optimization technique that determines the possible range of values an expression or variable can take during execution.
- SSA name
- Static Single Assignment form. In SSA, each variable is assigned a unique name the first time it is defined. This simplifies many compiler optimizations.
- control flow graph (CFG)
- A directed graph representing all execution paths in a program, where nodes are basic blocks and edges represent control flow transfers.
- GIMPLE
- GCC's internal three-address code representation, used as an intermediate language for optimizations.