mirror of
https://github.com/RPCS3/llvm-mirror.git
synced 2025-01-31 20:51:52 +01:00
4e5297ed76
When LSR processes code like int accumulator = 0; for (int i = 0; i < N; i++) { accummulator += i; use((double) accummulator); } It may decide to replace integer `accumulator` with a double Shadow IV to get rid of casts. The problem with that is that the `accumulator`'s value may overflow. Starting from this moment, the behavior of integer and double accumulators will differ. This patch strenghtens up the conditions of Shadow IV mechanism applicability. We only allow it for IVs that are proved to be `AddRec`s with `nsw`/`nuw` flag. Differential Revision: https://reviews.llvm.org/D37209 llvm-svn: 311986