[all-commits] [llvm/llvm-project] 8a3659: [SCCP] Use constant ranges for binary operators.

[Florian Hahn via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 8a36594a7ec1dba26686d1fb8bd6b56500bc4717
      https://github.com/llvm/llvm-project/commit/8a36594a7ec1dba26686d1fb8bd6b56500bc4717
  Author: Florian Hahn <flo at fhahn.com>
  Date:   2020-03-19 (Thu, 19 Mar 2020)

  Changed paths:
    M llvm/lib/Transforms/Scalar/SCCP.cpp
    M llvm/test/Transforms/SCCP/binaryops-range-special-cases.ll
    A llvm/test/Transforms/SCCP/ip-ranges-binaryops.ll
    M llvm/test/Transforms/SCCP/range-and.ll
    M llvm/test/Transforms/SCCP/vector-bitcast.ll

  Log Message:
  -----------
  [SCCP] Use constant ranges for binary operators.

If one of the operands of a binary operator is a constant range, we can
use ConstantRange::binaryOp to approximate the result.

We still handle single element constant ranges as we did previously,
with ConstantExpr::get(), because ConstantRange::binaryOp still gives
worse results in a few cases for single element ranges.

Also note that we bail out early if any of the operands is still unknown.

Reviewers: davide, efriedma, mssimpso

Reviewed By: efriedma

Differential Revision: https://reviews.llvm.org/D71936