[all-commits] [llvm/llvm-project] e18157: Add extra test for D116499 requested in review

[Philip Reames via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: e18157c26b8e2a442bced5aeea6b4d99f54a6adb
      https://github.com/llvm/llvm-project/commit/e18157c26b8e2a442bced5aeea6b4d99f54a6adb
  Author: Philip Reames <listmail at philipreames.com>
  Date:   2022-01-04 (Tue, 04 Jan 2022)

  Changed paths:
    M llvm/test/Analysis/ScalarEvolution/overflow-intrinsics-trip-count.ll

  Log Message:
  -----------
  Add extra test for D116499 requested in review


  Commit: b061d86c6930acef1b246874adf2f11e9120894c
      https://github.com/llvm/llvm-project/commit/b061d86c6930acef1b246874adf2f11e9120894c
  Author: Philip Reames <listmail at philipreames.com>
  Date:   2022-01-04 (Tue, 04 Jan 2022)

  Changed paths:
    M llvm/lib/Analysis/ScalarEvolution.cpp
    M llvm/test/Analysis/ScalarEvolution/overflow-intrinsics-trip-count.ll
    M llvm/test/CodeGen/PowerPC/negctr.ll

  Log Message:
  -----------
  [SCEV] Compute exit count from overflow check expressed w/ x.with.overflow intrinsics

This ports the logic we generate in instcombine for a single use x.with.overflow check for use in SCEV's analysis. The result is that we can prove trip counts for many checks, and (through existing logic) often discharge them.

Motivation comes from compiling a simple example with -ftrapv.

Differential Revision: https://reviews.llvm.org/D116499


Compare: https://github.com/llvm/llvm-project/compare/bc1df1fabb57...b061d86c6930