B3 should be able to compile trivial self-loops
https://bugs.webkit.org/show_bug.cgi?id=153802
rdar://problem/24465632
Reviewed by Michael Saboff.
Tail-duplicating a self-loop would mean doing a kind of loop unrolling. It wouldn't be
profitable even if it did work. It turns out that it doesn't work, because we edit the target
block before reading the source block, which breaks if the target and source block are the
same.
This disables tail duplication of self-loops, adds a test, and adds better validation for this
issue.
* b3/B3DuplicateTails.cpp:
* b3/B3Procedure.cpp:
(JSC::B3::Procedure::resetReachability):
* b3/testb3.cpp:
(JSC::B3::testComputeDivisionMagic):
(JSC::B3::testTrivialInfiniteLoop):
(JSC::B3::zero):
(JSC::B3::run):
git-svn-id: http://svn.webkit.org/repository/webkit/trunk@196035 268f45cc-cd09-0410-ab3c-d52691b4dbfc
4 files changed
