[PATCH] D64869: [SCEV] get more accurate range for AddExpr with NW flag

[ChenZheng via Phabricator via llvm-commits]

shchenz created this revision.
shchenz added reviewers: nikic, sanjoy, hfinkel, reames.
Herald added subscribers: llvm-commits, wuzish, hiraditya.
Herald added a project: LLVM.

for AddExpr ` (1 + %a)<nsw>`, if `%a` (LoopInvariant, such as function parameter) range is `fullset`, `1` range is `[1, 2)`, for now, constant range add operation will return `fullset` is any of its operand is `fullset`.

For above AddExpr, `(1 + %a)<nsw>` has No-Signed-Wrap flag, so `SINT_MIN` is not in `(1 + %a)<nsw>` range. But now we get a conservative range, `fullset`.

This patch is to improve this issue. This patch is based on patch https://reviews.llvm.org/D64868


https://reviews.llvm.org/D64869

Files:
  llvm/lib/Analysis/ScalarEvolution.cpp
  llvm/test/Analysis/ScalarEvolution/max-trip-count.ll
  llvm/test/Analysis/ScalarEvolution/trip-count12.ll
  llvm/test/Analysis/ScalarEvolution/trip-count9.ll

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