The function with uwtable attribute might be visited by the
stack unwinder, thus the link register should be considered
as clobbered after the execution of the branch and link
instruction (i.e. the definition of the machine instruction
can't be ignored) even when the callee function are marked
with noreturn.

llvm-svn: 202165

The aim in this patch is to reduce work that VirtRegRewriter needs to do when
telling MachineRegisterInfo which physregs are in use. Up until now
VirtRegRewriter::rewrite has been doing rewriting and populating def info and
then proceeding to set whether a physreg is used based this info for every
physreg that the target provides. This can be expensive when a target has an
unusually high number of supported physregs, and is a noticeable chunk of
compile time for small programs on such targets.

So to reduce compile time, this patch simply adds the use of a SparseSet to the
rewrite function that is used to flag each physreg that is encountered in a
MachineFunction. Afterward, rather than iterating over the set of all physregs
for a given target to set the physregs used in MachineRegisterInfo, the new way
is to iterate over the set of physregs that were actually encountered and set
in the SparseSet. This improves compile time because the existing rewrite
function was iterating over all MachineOperands already, and because the
iterations afterward to setPhysRegUsed is reduced by use of the SparseSet data.

llvm-svn: 200919

isPhysRegUsed if the unwind information is required.
Indeed, the runtime may need a correct stack to be able to unwind the call.

llvm-svn: 194271

PEI inserts a save/restore sequence for the link register, according to the
information it gets from the MachineRegisterInfo.
MachineRegisterInfo is populated by the VirtRegMap pass.
This pass was not aware of noreturn calls and was registering the definitions of
these calls the same way as regular operations.

Modify VirtRegPass so that it does not set the isPhysRegUsed information for
registers only defined by noreturn calls.
The rational is that a noreturn call is the "last instruction" of the program
(if it returns the behavior is undefined), so everything that is defined by it
cannot be used and will not interfere with anything else. Therefore, it is
pointless to account for then.

llvm-svn: 191349

Now that there can be multiple hint registers from targets, it doesn't
make sense to have a function that returns 'the' preferred register.

llvm-svn: 169190

Targets can provide multiple hints now, so getRegAllocPref() doesn't
make sense any longer because it only returns one preferred register.
Replace it with getSimpleHint() in the remaining heuristics. This
function only

llvm-svn: 169188

Virtual registers with a known preferred register are prioritized by
RAGreedy. This function makes the condition explicit without depending
on getRegAllocPref().

llvm-svn: 169179

Sooooo many of these had incorrect or strange main module includes.
I have manually inspected all of these, and fixed the main module
include to be the nearest plausible thing I could find. If you own or
care about any of these source files, I encourage you to take some time
and check that these edits were sensible. I can't have broken anything
(I strictly added headers, and reordered them, never removed), but they
may not be the headers you'd really like to identify as containing the
API being implemented.

Many forward declarations and missing includes were added to a header
files to allow them to parse cleanly when included first. The main
module rule does in fact have its merits. =]

llvm-svn: 169131

No functional change, just moved header files.

Targets can inject custom passes between register allocation and
rewriting. This makes it possible to tweak the register allocation
before rewriting, using the full global interference checking available
from LiveRegMatrix.

llvm-svn: 168806

Using the cached bit vector in MRI avoids comstantly allocating and
recomputing the reserved register bit vector.

llvm-svn: 165983

because LiveStackAnalysis was not preserved by VirtRegWriter. This caused
big stack usage regression in some cases.

rdar://12340383

llvm-svn: 164408

"#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)"

No functional change. Update r163339.

llvm-svn: 163653

No functional change.

llvm-svn: 163339

We will soon allow virtual register live ranges to overlap regunit live
ranges when the physreg is defined as a copy of the virtreg:

  %EAX = COPY %vreg5
  FOO %vreg5
  BAR %EAX<kill>

There is no real interference since %vreg5 and %EAX have the same value
where they overlap.

This patch prevents addKillFlags from adding virtreg kill flags to FOO
where the assigned physreg is overlapping the virtual register live
range.

llvm-svn: 163335

Add a getName function to MachineFunction. Use it in places that previously did getFunction()->getName(). Remove includes of Function.h that are no longer needed.

llvm-svn: 162347

This deduplicates some code from the optimizing register allocators, and
it means that it is now possible to change the register allocators'
solutions simply by editing the VirtRegMap between the register
allocator pass and the rewriter.

llvm-svn: 158249

OK, not really. We don't want to reintroduce the old rewriter hacks.

This patch extracts virtual register rewriting as a separate pass that
runs after the register allocator. This is possible now that
CodeGen/Passes.cpp can configure the full optimizing register allocator
pipeline.

The rewriter pass uses register assignments in VirtRegMap to rewrite
virtual registers to physical registers, and it inserts kill flags based
on live intervals.

These finalization steps are the same for the optimizing register
allocators: RABasic, RAGreedy, and PBQP.

llvm-svn: 158244

MRI keeps track of which physregs have been used. Make sure it gets
updated with all the regmask-clobbered registers.

Delete the closePhysRegsUsed() function which isn't necessary.

llvm-svn: 150830

llvm-svn: 148464

llvm-svn: 147725

This can only happen if the set of reserved registers changes during
register allocation.

<rdar://problem/10625436>

llvm-svn: 147486

This thing is looking a lot like a virtual register map now.

llvm-svn: 144486

Nobody cared, StackSlotColoring scans the instructions to find used stack
slots.

llvm-svn: 144485

Most of this stuff was supporting the old deferred spill code insertion
mechanism.  Modern spillers just edit machine code in place.

llvm-svn: 144484

The information was only used by the register allocator in
StackSlotColoring.

llvm-svn: 144482

For example:

  %vreg10:dsub_0<def,undef> = COPY %vreg1
  %vreg10:dsub_1<def> = COPY %vreg2

is rewritten as:

  %D2<def> = COPY %D0, %Q1<imp-def>
  %D3<def> = COPY %D1, %Q1<imp-use,kill>, %Q1<imp-def>

The first COPY doesn't care about the previous value of %Q1, so it
doesn't read that register.

The second COPY is a partial redefinition of %Q1, so it implicitly kills
and redefines that register.

This makes it possible to recognize instructions that can harmlessly
clobber the full super-register.  The write and don't read the
super-register.

llvm-svn: 141139

Fix the stats counters to reflect that.

llvm-svn: 139819

llvm-svn: 130996

We cannot rely on the <imp-def> operands added by LiveIntervals in all cases as
demonstrated by the test case.

llvm-svn: 130313

Turn them into noop KILL instructions instead. This lets the scavenger know when
super-registers are killed and defined.

llvm-svn: 128645

llvm-svn: 128143

The rewriter works almost identically to -rewriter=trivial, except it also
eliminates any identity copies.

This makes the new register allocators independent of VirtRegRewriter.cpp which
will be going away at the same time as RegAllocLinearScan.

llvm-svn: 125967

These functions not longer assert when passed 0, but simply return false instead.

No functional change intended.

llvm-svn: 123155

when no virtual registers have been allocated.

It was only used to resize IndexedMaps, so provide an IndexedMap::resize()
method such that

 Map.grow(MRI.getLastVirtReg());

can be replaced with the simpler

 Map.resize(MRI.getNumVirtRegs());

This works correctly when no virtuals are allocated, and it bypasses the to/from
index conversions.

llvm-svn: 123130

Print virtual registers numbered from 0 instead of the arbitrary
FirstVirtualRegister. The first virtual register is printed as %vreg0.
TRI::NoRegister is printed as %noreg.

llvm-svn: 123107

depending on TRI::FirstVirtualRegister.

Also use TRI::printReg instead of printing virtual registers directly.

llvm-svn: 123101

Use amazing new function call technology instead of writing identical code in
multiple places.

This fixes PR8604.

llvm-svn: 119306

llvm-svn: 115996

llvm-svn: 109045

The PowerPC floating point registers can represent both f32 and f64 via the
two register classes F4RC and F8RC. F8RC is considered a subclass of F4RC to
allow cross-class coalescing. This coalescing only affects whether registers
are spilled as f32 or f64.

Spill slots must be accessed with load/store instructions corresponding to the
class of the spilled register. PPCInstrInfo::foldMemoryOperandImpl was looking
at the instruction opcode which is wrong.

X86 has similar floating point register classes, but doesn't try to fold
memory operands, so there is no problem there.

llvm-svn: 97262