getIntPtrType support for multiple address spaces via a pointer type,
and also introduced a crasher bug in the constant folder reported in
PR14233.

These commits also contained several problems that should really be
addressed before they are re-committed. I have avoided reverting various
cleanups to the DataLayout APIs that are reasonable to have moving
forward in order to reduce the amount of churn, and minimize the number
of commits that were reverted. I've also manually updated merge
conflicts and manually arranged for the getIntPtrType function to stay
in DataLayout and to be defined in a plausible way after this revert.

Thanks to Duncan for working through this exact strategy with me, and
Nick Lewycky for tracking down the really annoying crasher this
triggered. (Test case to follow in its own commit.)

After discussing with Duncan extensively, and based on a note from
Micah, I'm going to continue to back out some more of the more
problematic patches in this series in order to ensure we go into the
LLVM 3.2 branch with a reasonable story here. I'll send a note to
llvmdev explaining what's going on and why.

Summary of reverted revisions:

r166634: Fix a compiler warning with an unused variable.
r166607: Add some cleanup to the DataLayout changes requested by
         Chandler.
r166596: Revert "Back out r166591, not sure why this made it through
         since I cancelled the command. Bleh, sorry about this!
r166591: Delete a directory that wasn't supposed to be checked in yet.
r166578: Add in support for getIntPtrType to get the pointer type based
         on the address space.
llvm-svn: 167221

llvm-svn: 167196

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

llvm-svn: 167119

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

llvm-svn: 167105

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

llvm-svn: 167103

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

llvm-svn: 167102

This patch migrates the stpcpy optimizations from the simplify-libcalls
pass into the instcombine library call simplifier.  Note that the
__stpcpy_chk simplifications were migrated in a previous commit.

llvm-svn: 167083

integers in that the code to handle split alloca-wide integer loads or
stores doesn't come first. It should, for the same reasons as with
integers, and the PR attests to that. Also had to fix a busted assert in
that this test case also covers.

llvm-svn: 167051

Thanks to Preston Briggs for catching this!

llvm-svn: 167045

When the switch-to-lookup tables transform landed in SimplifyCFG, it
was pointed out that this could be inappropriate for some targets.
Since there was no way at the time for the pass to know anything about
the target, an awkward reverse-transform was added in CodeGenPrepare
that turned lookup tables back into switches for some targets.

This patch uses the new TargetTransformInfo to determine if a
switch should be transformed, and removes
CodeGenPrepare::ConvertLoadToSwitch.

llvm-svn: 167011

checks to avoid performing compile-time arithmetic on PPCDoubleDouble.

Now that APFloat supports arithmetic on PPCDoubleDouble, those checks
are no longer needed, and we can treat the type like any other.

llvm-svn: 166958

wrapper returns a vector of integers when passed a vector of pointers) by having
getIntPtrType itself return a vector of integers in this case.  Outside of this
wrapper, I didn't find anywhere in the codebase that was relying on the old
behaviour for vectors of pointers, so give this a whirl through the buildbots.

llvm-svn: 166939

I don't think this is possible with the current implementation but that may change eventually.

llvm-svn: 166877

This turns loops like
  for (unsigned i = 0; i != n; ++i)
    p[i] = p[i+1];
into memmove, which has a highly optimized implementation in most libcs.

This was really easy with the new DependenceAnalysis :)

llvm-svn: 166875

Requires a lot less code and complexity on loop-idiom's side and the more
precise analysis can catch more cases, like the one I included as a test case.
This also fixes the edge-case miscompilation from PR9481.

Compile time performance seems to be slightly worse, but this is mostly due
to an extra LCSSA run scheduled by the PassManager and should be fixed there.

llvm-svn: 166874

smaller integer loads and stores.

The high-level motivation is that the frontend sometimes generates
a single whole-alloca integer load or store during ABI lowering of
splittable allocas. We need to be able to break this apart in order to
see the underlying elements and properly promote them to SSA values. The
hope is that this fixes some performance regressions on x86-32 with the
new SROA pass.

Unfortunately, this causes quite a bit of churn in the test cases, and
bloats some IR that comes out. When we see an alloca that consists soley
of bits and bytes being extracted and re-inserted, we now do some
splitting first, before building widened integer "bucket of bits"
representations. These are always well folded by instcombine however, so
this shouldn't actually result in missed opportunities.

If this splitting of all-integer allocas does cause problems (perhaps
due to smaller SSA values going into the RA), we could potentially go to
some extreme measures to only do this integer splitting trick when there
are non-integer component accesses of an alloca, but discovering this is
quite expensive: it adds yet another complete walk of the recursive use
tree of the alloca.

Either way, I will be watching build bots and LNT bots to see what
fallout there is here. If anyone gets x86-32 numbers before & after this
change, I would be very interested.

llvm-svn: 166662

GVN will now generate ptrtoint instructions for vectors of pointers.
Fixes PR14166.

llvm-svn: 166624

llvm-svn: 166607

Back out r166591, not sure why this made it through since I cancelled the command. Bleh, sorry about this!

llvm-svn: 166596

llvm-svn: 166591

This checkin also adds in some tests that utilize these paths and updates some of the
clients.

llvm-svn: 166578

every TU where it's implicitly instantiated, even if there's an implicit
instantiation for the same types available in another TU.

llvm-svn: 166470

llvm-svn: 166424

very small but very important bugfix:
  bool shouldExplore(Use *U) {
    Value *V = U->get();
    if (isa<CallInst>(V) || isa<InvokeInst>(V))
    [...]
should have read:
  bool shouldExplore(Use *U) {
    Value *V = U->getUser();
    if (isa<CallInst>(V) || isa<InvokeInst>(V))
Fixes PR14143!

llvm-svn: 166407

It broke selfhosting stage2 in several builders.

llvm-svn: 166406

calls can be marked tail.

llvm-svn: 166405

It passes all tests, produces better results than the old code but uses the
wrong pass, LoopDependenceAnalysis, which is old and unmaintained. "Why is it
still in tree?", you might ask. The answer is obviously: "To confuse developers."

Just swapping in the new dependency pass sends the pass manager into an infinte
loop, I'll try to figure out why tomorrow.

llvm-svn: 166399

Requires a lot less code and complexity on loop-idiom's side and the more
precise analysis can catch more cases, like the one I included as a test case.
This also fixes the edge-case miscompilation from PR9481. I'm not entirely
sure that all cases are handled that the old checks handled but LDA will
certainly become smarter in the future.

llvm-svn: 166390

llvm-svn: 166375

llvm-svn: 166340

Fixes PR13028.

llvm-svn: 166313

This can invalidate the iterators leading to use after frees and crashes.
Fixes PR12536.

llvm-svn: 166291

llvm-svn: 166264

This patch migrates the strcpy optimizations from the simplify-libcalls pass
into the instcombine library call simplifier.  Note also that StrCpyChkOpt
has been updated with a few simplifications that were being done in the
simplify-libcalls version of StrCpyOpt, but not in the migrated implementation
of StrCpyOpt.  There is no reason to overload StrCpyOpt with fortified and
regular simplifications in the new model since there is already a dedicated
simplifier for __strcpy_chk.

llvm-svn: 166198

operate purely on values. Sink the alloca loading and storing logic into
the rewrite routines that are specific to alloca-integer-rewrite
driving. This is just a refactoring here, but the subsequent step will
be to reuse the insertion and extraction logic when rewriting integer
loads and stores that have been split and decomposed into narrower loads
and stores.

No functionality changed other than different names for instructions.

llvm-svn: 166176

llvm-svn: 166175

The TargetTransform changes are breaking LTO bootstraps of clang.  I am
working with Nadav to figure out the problem, but I am reverting it for now
to get our buildbots working.

This reverts svn commits: 165665 165669 165670 165786 165787 165997
and I have also reverted clang svn 165741

llvm-svn: 166168

a pointer. A very bad idea. Let's not do that. Fixes PR14105.

Note that this wasn't *that* glaring of an oversight. Originally, these
routines were only called on offsets within an alloca, which are
intrinsically positive. But over the evolution of the pass, they ended
up being called for arbitrary offsets, and things went downhill...

llvm-svn: 166095

revision makes no sense. We cannot use the address space of the *post
indexed* type to conclude anything about a *pre indexed* pointer type's
size. More importantly, this index can never be over a pointer. We are
indexing over arrays and vectors here.

Of course, I have no test case here. Neither did the original patch. =/

llvm-svn: 166091

llvm-svn: 166053