llvm-svn: 145154

We've been hitting asserts in this code due to the many supported
combintions of modes (iv-rewrite/no-iv-rewrite) and IV types. This
second rewrite of the code attempts to deal with these cases systematically.

llvm-svn: 143546

silence -Wparentheses.

llvm-svn: 143534

Narrowest possible fix for PR11279.

llvm-svn: 143522

Fixes rdar://10359193 Indvar LinearFunctionTestReplace assertion

llvm-svn: 143183

It is not safe to sink an alloca into a stacksave/stackrestore pair, so don't do that. <rdar://problem/10352360>

llvm-svn: 143093

I rewrote the algorithm a while back so it doesn't require map lookup,
but neglected to change the data structure. This was caught by
llvm-gcc self host, not because there's anything special about
llvm-gcc, but because it is the only test for nondeterminism we
currently have. Unit tests don't work well for everything; we should
always try to have a nondeterminism stress test running.

Fixes PR11133: llvm-gcc self host .o mismatch after enable-iv-rewrite=false

llvm-svn: 142036

IVs.

Indvars previously chose randomly between congruent IVs. Now it will
bias the decision toward IVs that SCEVExpander likes to create. This
was not done to fix any problem, it's just a welcome side effect of
factoring code.

llvm-svn: 141633

llvm-svn: 140670

llvm-svn: 139842

llvm-svn: 139583

llvm-svn: 139579

llvm-svn: 139574

llvm-svn: 139517

better.

Don't immediately give up when an add operation can't be trivially
sign/zero-extended within a loop. If it has NSW/NUW flags, generate a
new expression with sign extended (non-recurrent) operand. As before,
if SCEV says that all sign extends are loop invariant, then we can
widen the operation.

llvm-svn: 139453

llvm-svn: 139375

llvm-svn: 139169

llvm-svn: 138651

insertion place.

llvm-svn: 138473

SimplifyIndVar utility since it is required.

llvm-svn: 137202

based on ScalarEvolution without changing the induction variable phis.

This utility is the main tool of IndVarSimplifyPass, but the pass also
restructures induction variables in strange ways that are sensitive to
pass ordering. This provides a way for other loop passes to simplify
new uses of induction variables created during transformation. The
utility may be used by any pass that preserves ScalarEvolution. Soon
LoopUnroll will use it.

The net effect in this checkin is to cleanup the IndVarSimplify pass
by factoring out the SimplifyIndVar algorithm into a standalone utility.

llvm-svn: 137197

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

llvm-svn: 137013

llvm-svn: 135684

to for it to be an an anon namespace and be in a header.

Eliminate some extraenous uses of tie.

llvm-svn: 135669

llvm-svn: 135581

llvm-svn: 135568

info. Holding Use* pointers is bad form even though it happened to
work in this case.

llvm-svn: 135566

llvm-svn: 135558

llvm-svn: 135426

For -disable-iv-rewrite, perform LFTR without generating a new
"canonical" induction variable. Instead find the "best" existing
induction variable for use in the loop exit test and compute the final
value of that IV for use in the new loop exit test. In short,
convert to a simple eq/ne exit test as long as it's cheap to do so.

llvm-svn: 135420

not interfere with BackedgeTakenCount computation.

llvm-svn: 135412

preheader for the sole purpose of LFTR, since LFTR itself is usually not
a clear optimization.

llvm-svn: 135409

llvm-svn: 135375

assertion I added in r135333. Check for the existence of a preheader
before expanding a recurrence.

llvm-svn: 135335

llvm-svn: 135334

LinearFunctionTestReplace rewrite. No functionality.

I've been wanting to group the indvar subphases into sections and
order them by their logical sequence. My next checkin adds functions
related to LFTR, and doing the reorg now should help reviewers. Since,
most of the code in IndVarSimplify.cpp has recently been replaced or
will be replaced soon, obscuring blame should not be an issue. This
seems like an ideal time to shuffle the code around.

I'm happy to take more suggestions for cleaning up the code. Or if
you've been wanting to cleanup anything in this file yourself, now is
a good time.

llvm-svn: 134941

careful about referencing values.

llvm-svn: 134537

llvm-svn: 134530

llvm-svn: 134441

Putting back the helper that I removed on 7/1 to do this right.

llvm-svn: 134423