3 Commits

Author SHA1 Message Date
Chad Rosier
3ac68db42d [ValueTracking] Improve isImpliedCondition when the dominating cond is false.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@267430 91177308-0d34-0410-b5e6-96231b3b80d8
2016-04-25 17:23:36 +00:00
Chad Rosier
2974be9d8b [ValueTracking] Improve isImpliedCondition for conditions with matching operands.
This patch improves SimplifyCFG to catch cases like:

  if (a < b) {
    if (a > b) <- known to be false
      unreachable;
  }

Phabricator Revision: http://reviews.llvm.org/D18905

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@266767 91177308-0d34-0410-b5e6-96231b3b80d8
2016-04-19 17:19:14 +00:00
Sanjoy Das
ee37e50003 [JumpThreading] Use dominating conditions to prove implications
Summary:
If P branches to Q conditional on C and Q branches to R conditional on
C' and C => C' then the branch conditional on C' can be folded to an
unconditional branch.

Reviewers: reames

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D13972

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@251557 91177308-0d34-0410-b5e6-96231b3b80d8
2015-10-28 21:27:08 +00:00