Michael Kruse 7fb4f732f5
[Polly] Avoid __builtin_assume circular context reasoning (#189350)
The conversion of SCEVs to isl::pw_aff may only be valid under
conditions that have to be confirmed via RTC. This also happens with
__builtin_assume. These user-added assumptions are then added to
ScopInfo::Context. However, the conclusion in ScopInfo::Context is then
also used to simplify ("gist") its own RTC preconditions in
ScopInfo::AssumedContext and ScopInfo::InvalidContext away.

Avoid by adding user assumptions with preconditions to
ScopInfo::DefinedBehaviourContext instead, which is not used to simplify
AssumedContext/InvalidContext.

Fixes #187922

Thanks @thapgua for the report
2026-03-30 11:08:23 +00:00
..

Polly - Polyhedral optimizations for LLVM
-----------------------------------------
http://polly.llvm.org/

Polly uses a mathematical representation, the polyhedral model, to represent and
transform loops and other control flow structures. Using an abstract
representation it is possible to reason about transformations in a more general
way and to use highly optimized linear programming libraries to figure out the
optimal loop structure. These transformations can be used to do constant
propagation through arrays, remove dead loop iterations, optimize loops for
cache locality, optimize arrays, apply advanced automatic parallelization, drive
vectorization, or they can be used to do software pipelining.