includes extracting ints for copying elsewhere and inserting ints when
copying into the alloca. This should fix the CanSROA assertion coming
out of Clang's regression test suite.

llvm-svn: 165931

and generally clean up the memset handling. It had rotted a bit as the
other rewriting logic got polished more.

llvm-svn: 165930

cases where we have partial integer loads and stores to an otherwise
promotable alloca to widen[1] those loads and stores to cover the entire
alloca and bitcast them into the appropriate type such that promotion
can proceed.

These partial loads and stores stem from an annoying confluence of ARM's
calling convention and ABI lowering and the FCA pre-splitting which
takes place in SROA. Clang lowers a { double, double } in-register
function argument as a [4 x i32] function argument to ensure it is
placed into integer 32-bit registers (a really unnerving implicit
contract between Clang and the ARM backend I would add). This results in
a FCA load of [4 x i32]* from the { double, double } alloca, and SROA
decomposes this into a sequence of i32 loads and stores. Inlining
proceeds, code gets folded, but at the end of the day, we still have i32
stores to the low and high halves of a double alloca. Widening these to
be i64 operations, and bitcasting them to double prior to loading or
storing allows promotion to proceed for these allocas.

I looked quite a bit changing the IR which Clang produces for this case
to be more friendly, but small changes seem unlikely to help. I think
the best representation we could use currently would be to pass 4 i32
arguments thereby avoiding any FCAs, but that would still require this
fix. It seems like it might eventually be nice to somehow encode the ABI
register selection choices outside of the parameter type system so that
the parameter can be a { double, double }, but the CC register
annotations indicate that this should be passed via 4 integer registers.

This patch does not address the second problem in PR14059, which is the
reverse: when a struct alloca is loaded as a *larger* single integer.

This patch also does not address some of the code quality issues with
the FCA-splitting. Those don't actually impede any optimizations really,
but they're on my list to clean up.

[1]: Pedantic footnote: for those concerned about memory model issues
here, this is safe. For the alloca to be promotable, it cannot escape or
have any use of its address that could allow these loads or stores to be
racing. Thus, widening is always safe.

llvm-svn: 165928

into static helper functions. They're really quite generic and are going
to be needed elsewhere shortly.

llvm-svn: 165927

Add an enum for the return and function indexes into the AttrListPtr object. This gets rid of some magic numbers.

llvm-svn: 165924

Convert the internal representation of the Attributes class into a pointer to an
opaque object that's uniqued by and stored in the LLVMContext object. The
Attributes class then becomes a thin wrapper around this opaque
object. Eventually, the internal representation will be expanded to include
attributes that represent code generation options, etc.

llvm-svn: 165917

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

llvm-svn: 165915

Erasing from the beginning or middle of the vector is expensive, remove_if can
do it in linear time even though it's a bit ugly without lambdas.

No functionality change.

llvm-svn: 165903

Remove the bitwise assignment OR operator from the Attributes class. Replace it with the equivalent from the builder class.

llvm-svn: 165895

Remove the bitwise XOR operator from the Attributes class. Replace it with the equivalent from the builder class.

llvm-svn: 165893

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

llvm-svn: 165875

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

llvm-svn: 165874

type coercion code, especially when targetting ARM. Things like [1
x i32] instead of i32 are very common there.

The goal of this logic is to ensure that when we are picking an alloca
type, we look through such wrapper aggregates and across any zero-length
aggregate elements to find the simplest type possible to form a type
partition.

This logic should (generally speaking) rarely fire. It only ends up
kicking in when an alloca is accessed using two different types (for
instance, i32 and float), and the underlying alloca type has wrapper
aggregates around it. I noticed a significant amount of this occurring
looking at stepanov_abstraction generated code for arm, and suspect it
happens elsewhere as well.

Note that this doesn't yet address truly heinous IR productions such as
PR14059 is concerning. Those result in mismatched *sizes* of types in
addition to mismatched access and alloca types.

llvm-svn: 165870

help the dragonegg builders, and no test case at this point, but this
was one dimly plausible case I spotted by inspection. Hopefully will get
a testcase from those bots soon-ish, and will tidy this up with proper
testing.

llvm-svn: 165869

llvm-svn: 165867

are single value types, the load and store should be directly based upon
the alloca and then bitcasting can fix the type as needed afterward.
This might in theory improve some of the IR coming out of SROA, but
I don't expect big changes yet and don't have any test cases on hand.
This is really just a cleanup/refactoring patch. The next patch will
cause this code path to be hit a lot more, actually get SROA to promote
more allocas and include several more test cases.

llvm-svn: 165864

llvm-svn: 165747

Add in the first iteration of support for llvm/clang/lldb to allow variable per address space pointer sizes to be optimized correctly.

llvm-svn: 165726

Add a new interface to allow IR-level passes to access codegen-specific information.

llvm-svn: 165665

namespace. Use the attribute's enum value instead. No functionality change
intended.

llvm-svn: 165610

Update EarlyCSE's SimpleValues to use Hashing.h for their hashes. Expanded the hashing and equality to allow for equality modulo commutativity for binary ops, and comparisons with swapping of predicates.

llvm-svn: 165509

llvm-svn: 165494

We use the enums to query whether an Attributes object has that attribute. The
opaque layer is responsible for knowing where that specific attribute is stored.

llvm-svn: 165488

Thanks to Benjamin for the raw test case. This one took about 50 times
longer to reduce than to fix. =/

llvm-svn: 165476

llvm-svn: 165469

llvm-svn: 165468

Refactor the AddrMode class out of TLI to its own header file.
This class is used by LSR and a number of places in the codegen.
This is the first step in de-coupling LSR from TLI, and creating
a new interface in between them.

llvm-svn: 165455

llvm-svn: 165402

llvm-svn: 165309

have an alloca or a parameter, since then the alloca test should make sense
to readers, while before it probably appears too specific.  No functionality
change.

llvm-svn: 165306

are in fact identity operations. We detect these and kill their
partitions so that even splitting is unaffected by them. This is
particularly important because Clang relies on emitting identity memcpy
operations for struct copies, and these fold away to constants very
often after inlining.

Fixes the last big performance FIXME I have on my plate.

llvm-svn: 165285

the rewrite visitor to make the fact that the speculation is completely
independent a bit more clear.

I promise that this is just a cut/paste of the one visitor and adding
the annonymous namespace wrappings. The diff may look completely
preposterous, it does in git for some reason.

llvm-svn: 165284

a pointer to a type, in order to remove the uses of getGlobalContext().

Patch by Tyler Nowicki.

llvm-svn: 165255

llvm-svn: 165238

cpyDest can be mutated in some cases, which would then cause a crash later if
indeed the memory was underaligned.  This brought down several buildbots, so
I guess the underaligned case is much more common than I thought!

llvm-svn: 165228

Currently, we re-visit allocas when something changes about the way they
might be *split* to allow better scalarization to take place. However,
we weren't handling the case when the *promotion* is what would change
the behavior of SROA. When an address derived from an alloca is stored
into another alloca, we consider the first to have escaped. If the
second is ever promoted to an SSA value, we will suddenly be able to run
the SROA pass on the first alloca.

This patch adds explicit support for this form if iteration. When we
detect a store of a pointer derived from an alloca, we flag the
underlying alloca for reprocessing after promotion. The logic works hard
to only do this when there is definitely going to be promotion and it
might remove impediments to the analysis of the alloca.

Thanks to Nick for the great test case and Benjamin for some sanity
check review.

llvm-svn: 165223

was less aligned than the old.  In the testcase this results in an overaligned
memset: the memset alignment was correct for the original memory but is too much
for the new memory.  Fix this by either increasing the alignment of the new
memory or bailing out if that isn't possible.  Should fix the gcc-4.7 self-host
buildbot failure.

llvm-svn: 165220

Sorry for this being broken so long. =/

As part of this, switch all of the existing tests to be Little Endian,
which is the behavior I was asserting in them anyways! Add in a new
big-endian test that checks the interesting behavior there.

Another part of this is to tighten the rules abotu when we perform the
full-integer promotion. This logic now rejects cases where there fully
promoted integer is a non-multiple-of-8 bitwidth or cases where the
loads or stores touch bits which are in the allocated space of the
alloca but are not loaded or stored when accessing the integer. Sadly,
these aren't really observable today as the rest of the pass will
already ensure the invariants hold. However, the latter situation is
likely to become a potential concern in the future.

Thanks to Benjamin and Duncan for early review of this patch. I'm still
looking into whether there are further endianness issues, please let me
know if anyone sees BE failures persisting past this.

llvm-svn: 165219

llvm-svn: 165209

llvm-svn: 165187