llvm-project

d755b04e - [SCEV] Fold zext(C+A)<nsw> -> (sext(C) + zext(A))<nsw> if possible. (#142599)

[SCEV] Fold zext(C+A)<nsw> -> (sext(C) + zext(A))<nsw> if possible. (#142599) Simplify zext(C+A)<nsw> -> (sext(C) + zext(A))<nsw> if * zext (C + A)<nsw> >=s 0 and * A >=s V. For now this is limited to cases where the first operand is a constant, so the SExt can be folded to a new constant. This can be relaxed in the future. The initial version checks for non-negative manually to limit compile-time, supporting only A = smax(C2, ..) where C2 >= abs(C) Alive2 proof of the general pattern and the test changes in zext-nuw.ll (times out in the online instance but verifies locally) https://alive2.llvm.org/ce/z/_BtyGy PR: github.com/llvm/llvm-project/pull/142599