llvm-svn: 157348

Now that the coalescer keeps live intervals and machine code in sync at
all times, it needs to deal with identity copies differently.

When merging two virtual registers, all identity copies are removed
right away. This means that other identity copies must come from
somewhere else, and they are going to have a value number.

Deal with such copies by merging the value numbers before erasing the
copy instruction. Otherwise, we leave dangling value numbers in the live
interval.

This fixes PR12927.

llvm-svn: 157340

llvm-svn: 157319

Part of rdar://11496790

llvm-svn: 157303

llvm-svn: 157274

llvm-svn: 157273

Also make sure registers aren't erased twice if the dead def mentions
the register twice.

This fixes PR12911.

llvm-svn: 157254

Fix use of an unitialized value in the LegalizeOps expansion for ISD::SUB.  No in-tree targets exercise this path.

Patch by Micah Villmow.

llvm-svn: 157215

llvm-svn: 157195

This helps compile time when the greedy register allocator splits live
ranges in giant functions. Without the bias, we would try to grow
regions through the giant edge bundles, usually to find out that the
region became too big and expensive.

If a live range has many uses in blocks near the giant bundle, the small
negative bias doesn't make a big difference, and we still consider
regions including the giant edge bundle.

Giant edge bundles are usually connected to landing pads or indirect
branches.

llvm-svn: 157174

With physreg joining out of the way, it is easy to recognize the
instructions that need their kill flags cleared while testing for
interference.

This allows us to skip the final scan of all instructions for an 11%
speedup of the coalescer pass.

llvm-svn: 157169

It can be necessary to restrict to a sub-class before accessing
sub-registers.

llvm-svn: 157164

When rewriting operands, make sure the new registers have a compatible
register class.

llvm-svn: 157163

may be RAUW'd by the recursive call to LegalizeOps; instead, retrieve
the other operands when calling UpdateNodeOperands.  Fixes PR12889.

llvm-svn: 157162

Found by valgrind.

llvm-svn: 157160

llvm-svn: 157155

Not all GR64 registers have sub_8bit sub-registers.

llvm-svn: 157150

X86 has 2-addr instructions with different constraints on the tied def
and use operands. One is GR32, one is GR32_NOSP.

llvm-svn: 157149

llvm-svn: 157148

This function adds copies to be erased to DupCopies, avoid also adding
them to DeadCopies.

llvm-svn: 157147

Avoid looking at the operands of a potentially erased instruction.

llvm-svn: 157146

llvm-svn: 157145

llvm-svn: 157144

That struct ought to be a LiveInterval implementation detail.

llvm-svn: 157143

llvm-svn: 157142

llvm-svn: 157137

Dead code elimination during coalescing could cause a virtual register
to be split into connected components. The following rewriting would be
confused about the already joined copies present in the code, but
without a corresponding value number in the live range.

Erase all joined copies instantly when joining intervals such that the
MI and LiveInterval representations are always in sync.

llvm-svn: 157135

Dead code and joined copies are now eliminated on the fly, and there is
no need for a post pass.

This makes the coalescer work like other modern register allocator
passes: Code is changed on the fly, there is no pending list of changes
to be committed.

llvm-svn: 157132

The late dead code elimination is no longer necessary.

The test changes are cause by a register hint that can be either %rdi or
%rax. The choice depends on the use list order, which this patch changes.

llvm-svn: 157131

Before rewriting uses of one value in A to register B, check that there
are no tied uses. That would require multiple A values to be rewritten.

This bug can't bite in the current version of the code for a fairly
subtle reason: A tied use would have caused 2-addr to insert a copy
before the use. If the copy has been coalesced, it will be found by the
same loop changed by this patch, and the optimization is aborted.

This was exposed by 400.perlbench and lua after applying a patch that
deletes joined copies aggressively.

llvm-svn: 157130

There is no reason to defer the collection of virtual registers whose
register class may be replaced with a larger class.

llvm-svn: 157125

This will remove the original def once it has no more uses.

llvm-svn: 157104

Remaining virtreg->physreg copies were rematerialized during
updateRegDefsUses(), but we already do the same thing in joinCopy() when
visiting the physreg copy instruction.

Eliminate the preserveSrcInt argument to reMaterializeTrivialDef(). It
is now always true.

llvm-svn: 157103

There is no need for these instructions to stick around since they are
known to be not dead.

llvm-svn: 157102

Dead copies cause problems because they are trivial to coalesce, but
removing them gived the live range a dangling end point. This patch
enables full dead code elimination which trims live ranges to their uses
so end points don't dangle.

DCE may erase multiple instructions. Put the pointers in an ErasedInstrs
set so we never risk visiting erased instructions in the work list.

There isn't supposed to be any dead copies entering RegisterCoalescer,
but they do slip by as evidenced by test/CodeGen/X86/coalescer-dce.ll.

llvm-svn: 157101

The dead code elimination with callbacks is still useful.

llvm-svn: 157100

No functional change.

llvm-svn: 157079

This will make it possible to filter out erased instructions later.

llvm-svn: 157073

Use a dedicated MachO load command to annotate data-in-code regions.
This is the same format the linker produces for final executable images,
allowing consistency of representation and use of introspection tools
for both object and executable files.

Data-in-code regions are annotated via ".data_region"/".end_data_region"
directive pairs, with an optional region type.

data_region_directive := ".data_region" { region_type }
region_type := "jt8" | "jt16" | "jt32" | "jta32"
end_data_region_directive := ".end_data_region"

The previous handling of ARM-style "$d.*" labels was broken and has
been removed. Specifically, it didn't handle ARM vs. Thumb mode when
marking the end of the section.

rdar://11459456

llvm-svn: 157062

llvm-svn: 157060