Yingwei Zheng bb9580a02b
[SCEV] Use ashr to adjust constant multipliers (#135534)
SCEV converts "-2 *nsw (i32 V)" into "2148473647 *nsw (i32 V)". But we
cannot preserve the nsw flag when the constant multiplier is negative.
This patch changes lshr to ashr so that we can preserve both nsw and nuw
flags.

Alive2 proof: https://alive2.llvm.org/ce/z/LZVSEa
Closes https://github.com/llvm/llvm-project/issues/135531.
2025-04-13 20:22:48 +08:00
..
2023-11-24 15:49:28 +01:00