rather than an int. Thankfully, this only causes LLVM to miss optimizations, not
generate incorrect code.

This just fixes the zext at the return. We still insert an i32 ZextAssert when
reading a function's arguments, but it is followed by a truncate and another i8
ZextAssert so it is not optimized.

llvm-svn: 127766

llvm-svn: 127764

plus the test where it used to break.", which broke Clang self-host of a
Debug+Asserts compiler, on OS X.

llvm-svn: 127763

llvm-svn: 127757

After live range splitting, an original value may be available in multiple
registers. Tracing back through the registers containing the same value, find
the best place to insert a spill, determine if the value has already been
spilled, or discover a reaching def that may be rematerialized.

This is only the analysis part. The information is not used for anything yet.

llvm-svn: 127698

llvm-svn: 127697

v2 = bitcast v1
...
v3 = bitcast v2
...
   = v3
=>
v2 = bitcast v1
...
   = v1
if v1 and v3 are of in the same register class.

bitcast between i32 and fp (and others) are often not nops since they
are in different register classes. These bitcast instructions are often
left because they are in different basic blocks and cannot be
eliminated by dag combine.

rdar://9104514

llvm-svn: 127668

zext(undef) = 0, because the top bits will be zero.

llvm-svn: 127649

and then go kablooie. The problem was that it was tracking the PHI nodes anew
each time into this function. But it didn't need to. And because the recursion
didn't know that a PHINode was visited before, it would go ahead and call
itself.

There is a testcase, but unfortunately it's too big to add. This problem will go
away with the EH rewrite.
<rdar://problem/8856298>

llvm-svn: 127640

Use the opportunity to get rid of the trailing underscore variable names.

llvm-svn: 127618

Remove the unused reserved_ bit vector, no functional change intended.

This doesn't break 'svn blame', this file really is all my fault.

llvm-svn: 127607

llvm-svn: 127600

llvm-svn: 127598

Use the virtual register number as a cache tag instead. They are not reused.

llvm-svn: 127561

This allows the allocator to free any resources used by the virtual register,
including physical register assignments.

llvm-svn: 127560

llvm-gcc-i386-linux-selfhost and llvm-x86_64-linux-checks buildbots.
The original log entry:
Remove optimization emitting a reference insted of label difference, since
it can create more relocations. Removed isBaseAddressKnownZero method,
because it is no longer used.

llvm-svn: 127540

llvm-svn: 127530

Live range splitting can create a number of small live ranges containing only a
single real use. Spill these small live ranges along with the large range they
are connected to with copies. This enables memory operand folding and maximizes
the spill to fill distance.

Work in progress with known bugs.

llvm-svn: 127529

There are too many compatibility problems with using mixed types in
std::upper_bound, and I don't want to spend 110 lines of boilerplate setting up
a call to a 10-line function. Binary search is not /that/ hard to implement
correctly.

I tried terminating the binary search with a linear search, but that actually
made the algorithm slower against my expectation. Most live intervals have less
than 4 segments. The early test against endIndex() does pay, and this version is
25% faster than plain std::upper_bound().

llvm-svn: 127522

protector insertion not working correctly with unreachable code. Since that
revision was rolled out, this test doesn't actual fail before this fix.

llvm-svn: 127497

llvm-svn: 127496

Remove optimization emitting a reference insted of label difference, since it can create more relocations. Removed isBaseAddressKnownZero method, because it is no longer used.

llvm-svn: 127478

Replace -dag-chain-limit flag with constant. It has survived a release cycle without being touched, so no longer needs to pollute the hidden-help text.

llvm-svn: 127468

The existing CompEnd predicate does not define a strict weak order as required
by the C++03 standard; therefore, its use as a predicate to std::upper_bound
is invalid. For a discussion of this issue, see
http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#270

This patch replaces the asymmetrical comparison with an iterator adaptor that
achieves the same effect while being strictly standard-conforming by ensuring
an apples-to-apples comparison.

llvm-svn: 127462

Avoid replacing the value of a directly stored load with the stored value if the load is indexed. rdar://9117613.

llvm-svn: 127440

llvm-svn: 127398

This makes it possible to register delegates and get callbacks when the spiller
edits live ranges.

llvm-svn: 127389

llvm-svn: 127388

llvm-svn: 127380

llvm-svn: 127376

flexible.

If it returns a register class that's different from the input, then that's the
register class used for cross-register class copies.
If it returns a register class that's the same as the input, then no cross-
register class copies are needed (normal copies would do).
If it returns null, then it's not at all possible to copy registers of the
specified register class.

llvm-svn: 127368

The damage done by physreg coalescing only depends on the number of instructions
the extended physreg live range covers. This fixes PR9438.

The heuristic is still luck-based, and physreg coalescing really should be
disabled completely. We need a register allocator with better hinting support
before that is possible.

Convert a test to FileCheck and force spilling by inserting an extra call. The
previous spilling behavior was dependent on misguided physreg coalescing
decisions.

llvm-svn: 127351

This helps cases like 2008-07-19-movups-spills.ll, but doesn't have an obvious impact on benchmarks

llvm-svn: 127347

llvm-svn: 127335

llvm-svn: 127331

llvm-svn: 127311

This will we used for keeping register allocator data structures up to date
while LiveRangeEdit is trimming live intervals.

llvm-svn: 127300

llvm-svn: 127295

LiveRangeEdit::eliminateDeadDefs() will eventually be used by coalescing,
splitting, and spilling for dead code elimination. It can delete chains of dead
instructions as long as there are no dependency loops.

llvm-svn: 127287

Patch by Olaf Krzikalla!

llvm-svn: 127264