The partitioning logic attempted to handle uses of an alloca with an
offset starting before the alloca so long as the use had some overlap
with the alloca itself. However, there was a bug where we tested
'(uint64_t)Offset >= AllocSize' without first checking whether 'Offset'
was positive. As a consequence, essentially every negative offset (that
is, starting *before* the alloca does) would be thrown out, even if it
was overlapping. The subsequent code to throw out negative offsets which
were actually non-overlapping was essentially dead. The code to *handle*
overlapping negative offsets was actually dead!

I've just removed all of this, and taught SROA to discard any uses which
start prior to the alloca from the beginning. It has the lovely property
of simplifying the code. =] All the tests still pass, and in fact no new
tests are needed as this is already covered by our testsuite. Fixing the
code so that negative offsets work the way the comments indicate they
were supposed to work causes regressions. That's how I found this.

Anyways, this is all progress in the correct direction -- tightening up
SROA to be maximally aggressive. Some day, I really hope to turn
out-of-bounds accesses to an alloca into 'unreachable'.

llvm-svn: 169120

Fixes PR14465.

Differential Revision: http://llvm-reviews.chandlerc.com/D148

llvm-svn: 169084

The original patch removed a bunch of code that the SjLjEHPrepare pass placed
into the entry block if all of the landing pads were removed during the
CodeGenPrepare class. The more natural way of doing things is to run the CGP
*before* we run the SjLjEHPrepare pass.

Make it so!

llvm-svn: 169044

The simplify-libcalls pass maintained a statistic to count the number
of library calls that have been simplified.  Now that library call
simplification is being carried out in instcombine the statistic should
be moved to there.

llvm-svn: 168975

depends on the IR infrastructure, there is no sense in it being off in
Support land.

This is in preparation to start working to expand InstVisitor into more
special-purpose visitors that are still generic and can be re-used
across different passes. The expansion will go into the Analylis tree
though as nothing in VMCore needs it.

llvm-svn: 168972

This revision attempts to recognize following population-count pattern:

 while(a) { c++; ... ; a &= a - 1; ... },
  where <c> and <a>could be used multiple times in the loop body.

 TODO: On X8664 and ARM, __buildin_ctpop() are not expanded to a efficent 
instruction sequence, which need to be improved in the following commits.

Reviewed by Nadav, really appreciate!

llvm-svn: 168931

the last invoke instruction in the function. This also removes the last landing
pad in an function. This is fine, but with SjLj EH code, we've already placed a
bunch of code in the 'entry' block, which expects the landing pad to stick
around.

When we get to the situation where CGP has removed the last landing pad, go
ahead and nuke the SjLj instructions from the 'entry' block.
<rdar://problem/12721258>

llvm-svn: 168930

This patch migrates the puts optimizations from the simplify-libcalls
pass into the instcombine library call simplifier.

All the simplifiers from simplify-libcalls have now been migrated to
instcombine.  Yay!  Just a few other bits to migrate (prototype attribute
inference and a few statistics) and simplify-libcalls can finally be put
to rest.

llvm-svn: 168925

This patch migrates the fputs optimizations from the simplify-libcalls
pass into the instcombine library call simplifier.

llvm-svn: 168893

This patch migrates the fwrite optimizations from the simplify-libcalls
pass into the instcombine library call simplifier.

llvm-svn: 168892

This patch migrates the fprintf optimizations from the simplify-libcalls
pass into the instcombine library call simplifier.

llvm-svn: 168891

delete those as well.

llvm-svn: 168829

This patch migrates the sprintf optimizations from the simplify-libcalls
pass into the instcombine library call simplifier.

llvm-svn: 168677

This patch migrates the printf optimizations from the simplify-libcalls
pass into the instcombine library call simplifier.

llvm-svn: 168604

This patch migrates the toascii optimizations from the simplify-libcalls
pass into the instcombine library call simplifier.

llvm-svn: 168580

This patch migrates the isascii optimizations from the simplify-libcalls
pass into the instcombine library call simplifier.

llvm-svn: 168579

This patch migrates the isdigit optimizations from the simplify-libcalls
pass into the instcombine library call simplifier.

llvm-svn: 168578

This patch migrates the *abs optimizations from the simplify-libcalls
pass into the instcombine library call simplifier.

llvm-svn: 168574

This patch migrates the ffs* optimizations from the simplify-libcalls
pass into the instcombine library call simplifier.

llvm-svn: 168571

It can delete the block, and the loop continues on free'd memory.
No change in output. Found by valgrind.

llvm-svn: 168525

Now if we can transform an alloca into a single vector value, but it has
subvector, non-element accesses, we form the appropriate shufflevectors
to allow SROA to proceed. This fixes PR14055 which pointed out a very
common pattern that SROA couldn't handle -- mixed vec3 and vec4
operations on a single alloca.

llvm-svn: 168418

printing functions themselves.

Part of PR14324 (which should have just been a patch to the list, but
hey...)

llvm-svn: 168362

The issue is that we may end up with newly OOB loads when speculating
a load into the predecessors of a PHI node, and this confuses the new
integer splitting logic in some cases, triggering an assertion failure.
In fact, the branch in question must be dead code as it loads from
a too-narrow alloca. Add code to handle this gracefully and leave the
requisite FIXMEs for both optimizing more aggressively and doing more to
aid sanitizing invalid code which triggers these patterns.

llvm-svn: 168361

llvm-svn: 168347

to properly handle the combinations of these with split integer loads
and stores. This essentially replaces Evan's r168227 by refactoring the
code in a different way, and trynig to mirror that refactoring in both
the load and store sides of the rewriting.

Generally speaking there was some really problematic duplicated code
here that led to poorly founded assumptions and then subtle bugs. Now
much of the code actually flows through and follows a more consistent
style and logical path. There is still a tiny bit of duplication on the
store side of things, but it is much less bad.

This also changes the logic to never re-use a load or store instruction
as that was simply too error prone in practice.

I've added a few tests (one a reduction of the one in Evan's original
patch, which happened to be the same as the report in PR14349). I'm
going to look at adding a few more tests for things I found and fixed in
passing (such as the volatile tests in the vectorizable predicate).

This patch has survived bootstrap, and modulo one bugfix survived
Duncan's test suite, but let me know if anything else explodes.

llvm-svn: 168346

removed in commit 168035, but I missed this bit).

llvm-svn: 168292

operands of the expression being written was wrongly thought to be reusable as
an inner node of the expression resulting in it turning up as both an inner node
*and* a leaf, creating a cycle in the def-use graph.  This would have caused the
verifier to blow up if things had gotten that far, however it managed to provoke
an infinite loop first.

llvm-svn: 168291

Teach SROA rewriteVectorizedStoreInst to handle cases when the loaded value is narrower than the stored value. rdar://12713675

llvm-svn: 168227

the utility for extracting a chain of operations from the IR, thought that it
might as well combine any constants it came across (rather than just returning
them along with everything else).  On the other hand, the factorization code
would like to see the individual constants (this is quite reasonable: it is
much easier to pull a factor of 3 out of 2*3 than it is to pull it out of 6;
you may think 6/3 isn't so hard, but due to overflow it's not as easy to undo
multiplications of constants as it may at first appear).  This patch therefore
makes LinearizeExprTree stupider: it now leaves optimizing to the optimization
part of reassociate, and sticks to just analysing the IR.

llvm-svn: 168035

This patch migrates the math library call simplifications from the
simplify-libcalls pass into the instcombine library call simplifier.

I have typically migrated just one simplifier at a time, but the math
simplifiers are interdependent because:

   1. CosOpt, PowOpt, and Exp2Opt all depend on UnaryDoubleFPOpt.
   2. CosOpt, PowOpt, Exp2Opt, and UnaryDoubleFPOpt all depend on
      the option -enable-double-float-shrink.

These two factors made migrating each of these simplifiers individually
more of a pain than it would be worth.  So, I migrated them all together.

llvm-svn: 167815

llvm-svn: 167787

The assertion is trigged when the Reassociater tries to transform expression
     ... + 2 * n * 3 + 2 * m + ...
  into:
     ... + 2 * (n*3 + m).

In the process of the transformation, a helper routine folds the constant 2*3 into 6,
confusing optimizer which is trying the to eliminate the common factor 2, and cannot
find 2 any more. 

Review is pending. But I'd like commit first in order to help those who are waiting 
for this fix. 

llvm-svn: 167740

llvm-svn: 167698

This patch migrates the memset optimizations from the simplify-libcalls
pass into the instcombine library call simplifier.

llvm-svn: 167689

This patch migrates the memmove optimizations from the simplify-libcalls
pass into the instcombine library call simplifier.

llvm-svn: 167687

This patch migrates the memcpy optimizations from the simplify-libcalls
pass into the instcombine library call simplifier.

llvm-svn: 167686

This patch migrates the memcmp optimizations from the simplify-libcalls
pass into the instcombine library call simplifier.

llvm-svn: 167683

This patch migrates the strstr optimizations from the simplify-libcalls
pass into the instcombine library call simplifier.

llvm-svn: 167682

This patch migrates the strcspn optimizations from the simplify-libcalls
pass into the instcombine library call simplifier.

llvm-svn: 167675

This patch migrates the strspn optimizations from the simplify-libcalls
pass into the instcombine library call simplifier.

llvm-svn: 167568