[all-commits] [llvm/llvm-project] 4a5899: [SCCP] Use constant ranges for PHI nodes.

[Florian Hahn via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 4a58996dd2d226063bc9703c4722e06a5d041b23
      https://github.com/llvm/llvm-project/commit/4a58996dd2d226063bc9703c4722e06a5d041b23
  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
    M llvm/test/Transforms/SCCP/ip-constant-ranges.ll
    A llvm/test/Transforms/SCCP/ip-ranges-phis.ll
    A llvm/test/Transforms/SCCP/phis.ll
    M llvm/test/Transforms/SCCP/range-and.ll

  Log Message:
  -----------
  [SCCP] Use constant ranges for PHI nodes.

For PHIs with multiple incoming values, we can improve precision by
using constant ranges for integers. We can over-approximate phis
by merging the incoming values.

Reviewers: davide, efriedma, mssimpso

Reviewed By: efriedma

Differential Revision: https://reviews.llvm.org/D71933