ssa, so it has to be run really early in the pipeline. Any replacement
should probably use the SSAUpdater.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@138841 91177308-0d34-0410-b5e6-96231b3b80d8
Optimize chained bitcasts of the form A->B->A.
Undo r138722 and change isEliminableCastPair to allow this case.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@138756 91177308-0d34-0410-b5e6-96231b3b80d8
In theory this could be extended to other instructions, eg. division by zero, but it's likely that it will "miscompile" some code because people depend on div by zero not trapping. NULL pointer dereference usually leads to a crash so we should be on the safe side.
This shrinks the size of a Release clang by 16k on x86_64.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@138618 91177308-0d34-0410-b5e6-96231b3b80d8
known-incremented level, because the two concepts can be used
to prove the saftey of a retain+release removal in different
ways.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@138016 91177308-0d34-0410-b5e6-96231b3b80d8
making random bad assumptions about instructions which are not explicitly listed.
Includes fix for rdar://9956541, a version of "undef ^ undef should return
0 because it's easier than arguing with users".
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@137777 91177308-0d34-0410-b5e6-96231b3b80d8
This commit includes a mention of the landingpad instruction, but it's not
changing the behavior around it. I think the current behavior is correct,
though. Bill, can you double-check that?
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@137691 91177308-0d34-0410-b5e6-96231b3b80d8
of the instruction.
Note that this change affects the existing non-atomic load and store
instructions; the parser now accepts both forms, and the change is noted
in the release notes.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@137527 91177308-0d34-0410-b5e6-96231b3b80d8
the retains and releases all use the same SSA pointer value.
Also, don't let CFG hazards disrupt nested retain+release pair
optimizations.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@137399 91177308-0d34-0410-b5e6-96231b3b80d8
SCEV unrolling can unroll loops with arbitrary induction variables. It
is a prerequisite for -disable-iv-rewrite performance. It is also
easily handles loops of arbitrary structure including multiple exits
and is generally more robust.
This is under a temporary option to avoid affecting default
behavior for the next couple of weeks. It is needed so that I can
checkin unit tests for updateUnloop.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@137384 91177308-0d34-0410-b5e6-96231b3b80d8
These are not individual bug fixes. I had to rewrite a good chunk of
the unroller to make it sane. I think it was getting lucky on trivial
completely unrolled loops with no early exits. I included some fairly
simple unit tests for partial unrolling. I didn't do much stress
testing, so it may not be perfect, but should be usable now.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@137190 91177308-0d34-0410-b5e6-96231b3b80d8
recurrence, the initial values low bits can sometimes be ignored.
To take advantage of this, added FoldIVUser to IndVarSimplify to fold
an IV operand into a udiv/lshr if the operator doesn't affect the
result.
-indvars -disable-iv-rewrite now transforms
i = phi i4
i1 = i0 + 1
idx = i1 >> (2 or more)
i4 = i + 4
into
i = phi i4
idx = i0 >> ...
i4 = i + 4
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@137013 91177308-0d34-0410-b5e6-96231b3b80d8
Don't replace a gep/bitcast with 'undef' because that will form a "free(undef)"
which in turn means "unreachable". What we wanted was a no-op. Instead, analyze
the whole tree and look for all the instructions we need to delete first, then
delete them second, not relying on the use_list to stay consistent.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@136752 91177308-0d34-0410-b5e6-96231b3b80d8
