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JUNE 15, 2026
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match.pd Performance Win

Match.pd: Added pattern to simplify nested boolean comparisons.

A new pattern in match.pd simplifies `(bool >= A) >= A` expressions to `bool >= A`.

This commit introduces a new pattern to GCC’s match.pd file, which optimizes expressions of the form (bool >= A) >= A to bool >= A. This simplification reduces code complexity and can potentially improve performance by eliminating redundant comparisons. New test cases are included to verify the correctness of the new pattern.

In Details

The match.pd file contains pattern-matching rules used during GCC's tree optimization phase. This commit adds a new rule (bool >= A) >= A -> bool >= A to simplify expressions involving redundant comparisons. This pattern is applied during tree-ssa optimization. The new test cases gcc.dg/tree-ssa/pr119422.c and gcc.dg/tree-ssa/pr119422-2.c validate the new pattern.

For Context

Compilers use optimization techniques to simplify code and improve performance. One such technique is pattern matching, where the compiler identifies specific code patterns and replaces them with simpler, equivalent code. This commit adds a new pattern to GCC that simplifies nested boolean comparisons, potentially making the code smaller and faster.

Filed Under: optimizationpattern matchingtree-ssa