[SPARSE,0/4] fix/improve canonicalization of signed compares

Message

Luc Van Oostenryck April 18, 2021, 3:32 p.m. UTC

This series contains the following:
1) signed compares against a constant are now canonicalized towards 0
   so that (x >= 0) doesn't become (x > -1)
2) a signed compare like (x >= 0 && x <= C) is simplified into the
   unsigned compare: (x <= C)
   
This series is also available for review and testing at:
  git://git.kernel.org/pub/scm/devel/sparse/sparse.git optim-and-cmp

Luc Van Oostenryck (4):
  canonicalize constant signed compares toward zero
  add testcases for AND(x > 0, x <= C) --> x u<= C
  add helper is_positive()
  simplify AND(x >= 0, x < C) --> (unsigned)x < C

 linearize.h                           |  5 ++
 simplify.c                            | 45 +++++++++++++---
 validation/optim/canonical-cmp-zero.c | 74 +++++++++++++++++++++++++++
 validation/optim/range-check1.c       | 16 ++++++
 validation/optim/range-check2.c       | 14 +++++
 5 files changed, 148 insertions(+), 6 deletions(-)
 create mode 100644 validation/optim/canonical-cmp-zero.c
 create mode 100644 validation/optim/range-check1.c
 create mode 100644 validation/optim/range-check2.c


base-commit: eb4cdd21b7d0cedbbeff7f70e24473706ccce5a6