This helps generate better code in functions with high register
pressure.

The previous version of compact region splitting caused regressions
because the regions were a bit too large. A stronger negative bias
applied in r136832 fixed this problem.

llvm-svn: 136836

Do not drop undef debug values. These are used as range termination marker by live debug variable pass.

llvm-svn: 136834

Apply twice the negative bias on transparent blocks when computing the
compact regions. This excludes loop backedges from the region when only
one of the loop blocks uses the register.

Previously, we would include the backedge in the region if the loop
preheader and the loop latch both used the register, but the loop header
didn't.

When both the header and latch blocks use the register, we still keep it
live on the backedge.

llvm-svn: 136832

lib/CodeGen/RegAllocGreedy.cpp:1176:18: warning: unused variable 'B' [-Wunused-variable]
    if (unsigned B = Cand.getBundles(BundleCand, BestCand)) {
                 ^
lib/CodeGen/RegAllocGreedy.cpp:1188:18: warning: unused variable 'B' [-Wunused-variable]
    if (unsigned B = Cand.getBundles(BundleCand, 0)) {
                 ^

llvm-svn: 136831

llvm-svn: 136828

llvm-svn: 136826

This is some of my original LLVM code. *wipes tear*

llvm-svn: 136821

llvm-svn: 136816

New approach to r136737: insert the necessary fences for atomic ops in platform-independent code, since a bunch of platforms (ARM, Mips, PPC, Alpha are the relevant targets here) need to do essentially the same thing.

I think this completes the basic CodeGen for atomicrmw and cmpxchg.

llvm-svn: 136813

llvm-svn: 136803

llvm-svn: 136802

to notify SCEV of a change. Add forgetLoop in a couple of those places.

llvm-svn: 136797

llvm-svn: 136795

This fixes PR10575.

llvm-svn: 136787

llvm-svn: 136768

llvm-svn: 136759

  - use SmallVectorImpl& for the function argument.
  - ignore the operands on the GEP, even if they aren't constant! Much as we
    pretend the malloc succeeds, we pretend that malloc + whatever-you-GEP'd-by
    is not null. It's magic!

llvm-svn: 136757

Add this back in for now. There are still a few passes which create unwind instructions at the moment.

llvm-svn: 136756

Don't replace a gep/bitcast with 'undef' because that will form a "free(undef)"
which in turn means "unreachable". What we wanted was a no-op. Instead, analyze
the whole tree and look for all the instructions we need to delete first, then
delete them second, not relying on the use_list to stay consistent.

llvm-svn: 136752

the function, because the UnwindInst is going away.

llvm-svn: 136751

llvm-svn: 136742

This information is not used for anything yet.

llvm-svn: 136741

With a 'FirstDef' field right there, it is very confusing that FirstUse
refers to an instruction that may be a def.

llvm-svn: 136739

ARM backend support for atomicrmw and cmpxchg with non-monotonic ordering.  Not especially pretty, but seems to work well enough.  If this looks okay, I'll put together similar patches for Mips, PPC, and Alpha.

llvm-svn: 136737

This is either an invalid SlotIndex, or valno->def for the first value
defined inside the block. PHI values are not counted as defined inside
the block.

The FirstDef field will be used when estimating the cost of spilling
around a block.

llvm-svn: 136736

llvm-svn: 136735

malloc call.

llvm-svn: 136732

The PrefBoth constraint is used for blocks that ideally want a live-in
value both on the stack and in a register. This would be used by a block
that has a use before interference forces a spill.

Secondly, add the ChangesValue flag to BlockConstraint. This tells
SpillPlacement if a live-in value on the stack can be reused as a
live-out stack value for free. If the block redefines the virtual
register, a spill would be required for that.

This extra information will be used by SpillPlacement to more accurately
calculate spill costs when a value can exist both on the stack and in a
register.

The simplest example is a basic block that reads the virtual register,
but doesn't change its value. Spilling around such a block requires a
reload, but no spill in the block.

The spiller already knows this, but the spill placer doesn't. That can
sometimes lead to suboptimal regions.

llvm-svn: 136731

llvm-svn: 136727

llvm-svn: 136723

llvm-svn: 136722

externally visable, create a local symbol to use in the CFE. If not, use the
function label itself.

Fixes PR10420.

llvm-svn: 136716

The testcase looks extremely fragile, so I'm adding an assertion which should catch any cases like this.

llvm-svn: 136711

Fix the broken encodings for the VFP vmov.f32 and vmov.f64 instructions, as well as the comments that explain them incorrectly.

llvm-svn: 136707

llvm-svn: 136705

Use a more descriptive name so the code is more self-documenting.

llvm-svn: 136704

This unbreaks some tests.

llvm-svn: 136692

  shuffle (scalar_to_vector (load (ptr + 4))), undef, <0, 0, 0, 0>
To:
  shuffle (vload ptr)), undef, <1, 1, 1, 1>
Fix PR10494

llvm-svn: 136691

llvm-svn: 136690

to compile a working hello world on FreeBSD/PPC32.

llvm-svn: 136689