llvm-svn: 164940

alignment requirements of the new alloca. As one consequence which was
reported as a bug by Duncan, we overaligned memcpy calls to ranges of
allocas after they were rewritten to types with lower alignment
requirements. Other consquences are possible, but I don't have any test
cases for them.

llvm-svn: 164937

Fixes PR13985.

llvm-svn: 164934

a pair of instructions, one for the used pointer and the second for the
user. This simplifies the representation and also makes it more dense.

This was noticed because of the miscompile in PR13926. In that case, we
were running up against a fundamental "bad idea" in the speculation of
PHI and select instructions: the speculation and rewriting are
interleaved, which requires phi speculation to also perform load
rewriting! This is bad, and causes us to miss opportunities to do (for
example) vector rewriting only exposed after PHI speculation, etc etc.
It also, in the old system, required us to insert *new* load uses into
the current partition's use list, which would then be ignored during
rewriting because we had already extracted an end iterator for the use
list. The appending behavior (and much of the other oddities) stem from
the strange de-duplication strategy in the PartitionUse builder.
Amusingly, all this went without notice for so long because it could
only be triggered by having *different* GEPs into the same partition of
the same alloca, where both different GEPs were operands of a single
PHI, and where the GEP which was not encountered first also had multiple
uses within that same PHI node... Hence the insane steps required to
reproduce.

So, step one in fixing this fundamental bad idea is to make the
PartitionUse actually contain a Use*, and to make the builder do proper
deduplication instead of funky de-duplication. This is enough to remove
the appending behavior, and fix the miscompile in PR13926, but there is
more work to be done here. Subsequent commits will lift the speculation
into its own visitor. It'll be a useful step toward potentially
extracting all of the speculation logic into a generic utility
transform.

The existing PHI test case for repeated operands has been made more
extreme to catch even these issues. This test case, run through the old
pass, will exactly reproduce the miscompile from PR13926. ;] We were so
close here!

llvm-svn: 164925

source of false positives due to globals being declared in a header with some
kind of incomplete (small) type, but the actual definition being bigger.

llvm-svn: 164912

llvm-svn: 164911

A DAGCombine optimization for merging consecutive stores. This optimization is not profitable in many cases
because moden processos can store multiple values in parallel, and preparing the consecutive store requires
some work.  We only handle these cases:

1. Consecutive stores where the values and consecutive loads. For example:
 int a = p->a;
 int b = p->b;
 q->a = a;
 q->b = b;

2. Consecutive stores where the values are constants. Foe example:
 q->a = 4;
 q->b = 5;

llvm-svn: 164910

llvm-svn: 164899

llvm-svn: 164898

alignment could lose it due to the alloca type moving down to a much
smaller alignment guarantee.

Now SROA will actively compute a proper alignment, factoring the target
data, any explicit alignment, and the offset within the struct. This
will in some cases lower the alignment requirements, but when we lower
them below those of the type, we drop the alignment entirely to give
freedom to the code generator to align it however is convenient.

Thanks to Duncan for the lovely test case that pinned this down. =]

llvm-svn: 164891

buildbots.  Original commit message:

A DAGCombine optimization for merging consecutive stores. This optimization is not profitable in many cases
because moden processos can store multiple values in parallel, and preparing the consecutive store requires
some work.  We only handle these cases:

1. Consecutive stores where the values and consecutive loads. For example:
  int a = p->a;
  int b = p->b;
  q->a = a;
  q->b = b;

2. Consecutive stores where the values are constants. Foe example:
  q->a = 4;
  q->b = 5;

llvm-svn: 164890

A DAGCombine optimization for merging consecutive stores. This optimization is not profitable in many cases
because moden processos can store multiple values in parallel, and preparing the consecutive store requires
some work.  We only handle these cases:

1. Consecutive stores where the values and consecutive loads. For example:
  int a = p->a;
  int b = p->b;
  q->a = a;
  q->b = b;

2. Consecutive stores where the values are constants. Foe example:
  q->a = 4;
  q->b = 5;

llvm-svn: 164885

llvm-svn: 164867

llvm-svn: 164866

llvm-svn: 164849

llvm-svn: 164845

llvm-svn: 164842

llvm-svn: 164840

CorrelatedPropagation: BasicBlock::removePredecessor can simplify PHI nodes. If the it's the condition of a SwitchInst, reload it.

Fixes PR13972.

llvm-svn: 164818

Fixes PR13968.

llvm-svn: 164815

llvm-svn: 164814

llvm-svn: 164800

llvm-svn: 164799

llvm-svn: 164798

llvm-svn: 164797

llvm-svn: 164796

The new coalescer is better at merging values into unused vector lanes,
improving NEON code.

llvm-svn: 164794

llvm-svn: 164787

llvm-svn: 164786

If the width is very large it gets truncated from uint64_t to uint32_t when
passed to TD->fitsInLegalInteger. The truncated value can fit in a register.
This manifested in massive memory usage or crashes (PR13946).

llvm-svn: 164784

Fixes PR13943.

llvm-svn: 164778

Revert 'Fix a typo 'iff' => 'if''. iff is an abreviation of if and only if. See: http://en.wikipedia.org/wiki/If_and_only_if Commit 164767

llvm-svn: 164768

llvm-svn: 164767

llvm-svn: 164763

This is a preliminary step towards ELF support; currently ARMFastISel hasn't
been used for ELF object files yet.

llvm-svn: 164759

llvm-svn: 164757

llvm-svn: 164754

llvm-svn: 164751

llvm-svn: 164750

llvm-svn: 164749