THURSDAY, AUGUST 27, 2026
gcc/tree-optimization Performance Win
Handle differing signs in MOD range operations.
Range analysis now correctly handles MOD operations with differing signs.
The range analysis optimization pass has been improved to correctly handle modulo operations involving operands with different signs. A new helper function, same_quotient, was introduced to manage this, and it’s now used within the wi_fold function.
In Details
The operator_trunc_mod::wi_fold function in range-op.cc now correctly handles modulo operations where the operands might have different signs. This is achieved by introducing a new helper function, operator_trunc_mod::same_quotient, which likely determines if the quotient of two numbers is the same regardless of their signs. This improves the accuracy of range analysis for modulo operations.
For Context
- range analysis
- An optimization technique that determines the possible range of values a variable can take during program execution. This information is used to eliminate redundant checks or simplify computations.
- MOD
- The modulo operator, which returns the remainder of a division operation.
- WI-fold
- A function likely related to 'Widening Integer' folding, a compiler optimization technique that simplifies expressions involving integer operations by propagating range information.