PHI values may be deleted, causing the flags to be wrong. This fixes PR9616.

llvm-svn: 129092

When a virtual register has a single value that is defined as a copy of a
reserved register, permit that copy to be joined. These virtual register are
usually copies of the stack pointer:

  %vreg75<def> = COPY %ESP; GR32:%vreg75
  MOV32mr %vreg75, 1, %noreg, 0, %noreg, %vreg74<kill>
  MOV32mi %vreg75, 1, %noreg, 8, %noreg, 0
  MOV32mi %vreg75<kill>, 1, %noreg, 4, %noreg, 0
  CALLpcrel32 ...

Coalescing these virtual registers early decreases register pressure.
Previously, they were coalesced by RALinScan::attemptTrivialCoalescing after
register allocation was completed.

The lower register pressure causes the mcinst-lowering-cmp0.ll test case to fail
because it depends on linear scan spilling a particular register.

I am deleting 2008-08-05-SpillerBug.ll because it is counting the number of
instructions emitted, and its revision history shows the 'correct' count being
edited many times.

llvm-svn: 128845

We don't expect the real "powf()" on some hosts (and powf() would be available on other hosts).
For consistency, std::pow(double,double) may be called instead.
Or, precision issue might attack us, to see unstable regalloc and stack coloring.

llvm-svn: 128629

This is not supposed to happen, but I have seen the x86 rematter getting
confused when rematerializing partial redefs.

llvm-svn: 127857

I have convinced myself that it can only happen when a phi value dies. When it
happens, allocate new virtual registers for the components.

llvm-svn: 127827

llvm-svn: 127771

llvm-svn: 127388

llvm-svn: 127192

In this case, the value need to be available at the load index instead of the
normal use index.

llvm-svn: 127167

We need to wait until we meet a PHIDef in its defining block before resurrecting
PHIKills in the predecessors.

This should unbreak the llvm-gcc-build-x86_64-darwin10-x-mingw32-x-armeabi bot.

llvm-svn: 126905

llvm-svn: 126815

llvm-svn: 126806

llvm-svn: 126805

Simplify the spill weight calculation a bit by bypassing
getApproximateInstructionCount() and using LiveInterval::getSize() directly.
This changes the computed spill weights, but only by a constant factor in each
function. It should not affect how spill weights compare against each other, and
so it shouldn't affect code generation.

llvm-svn: 125530

No functional changes intended.

llvm-svn: 125231

This is a lot easier than trying to get kill flags right during live range
splitting and rematerialization.

llvm-svn: 125113

After uses of a live range are removed, recompute the live range to only cover
the remaining uses. This is necessary after rematerializing the value before
some (but not all) uses.

llvm-svn: 125058

In that case we simply ignore the landing pad and split live ranges before the
first terminator.

llvm-svn: 124907

A live range cannot be split everywhere in a basic block. A split must go before
the first terminator, and if the variable is live into a landing pad, the split
must happen before the call that can throw.

llvm-svn: 124894

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

No functional change intended.

llvm-svn: 123155

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

Always spill the full representative register at any point where any subregister
is live.

This fixes PR8620 which caused the old logic to get confused and not spill
anything at all.

The fundamental problem here is that the coalescer is too aggressive about
physical register coalescing. It sometimes makes it impossible to allocate
registers without these emergency spills.

llvm-svn: 119375

The live range of a register defined by an early clobber starts at the use slot,
not the def slot.

Except when it is an early clobber tied to a use operand. Then it starts at the
def slot like a standard def.

llvm-svn: 119305

This reverts r119183 which borke the buildbots.

llvm-svn: 119270

The live range of a register defined by an early clobber starts at the use slot,
not the def slot.

llvm-svn: 119183

benchmarks hitting an assertion.
Adds LiveIntervalUnion::collectInterferingVRegs.
Fixes "late spilling" by checking for any unspillable live vregs among
all physReg aliases.

llvm-svn: 118701

SlotIndexes when available.

llvm-svn: 117392

perform initialization without static constructors AND without explicit initialization
by the client.  For the moment, passes are required to initialize both their
(potential) dependencies and any passes they preserve.  I hope to be able to relax
the latter requirement in the future.

llvm-svn: 116334

This helps hiding the LiveRange class which really should be private.

llvm-svn: 116244

llvm-svn: 115996

Removed VNInfo::isDefAccurate(). Def "accuracy" can be checked by testing whether LiveIntervals::getInstructionFromIndex(def) returns NULL.

llvm-svn: 114791

llvm-svn: 114779

PHI elimination shouldn't require machineloopinfo since it's used at -O0. Move the requirement to LiveIntervalAnalysis instead. Note this does not change the number of times machineloopinfo is computed.

llvm-svn: 111285

llvm-svn: 110944

When the normalizeSpillWeights function was introduced, I forgot to remove this
normalization.

This change could affect register allocation. Hopefully for the better.

llvm-svn: 110119

llvm-svn: 109045

TII::isMoveInstr is going tobe completely removed.

llvm-svn: 108507

llvm-svn: 108013

inserted in a MBB, and return an already inserted MI.

This target API change is necessary to allow foldMemoryOperand to call
storeToStackSlot and loadFromStackSlot when folding a COPY to a stack slot
reference in a target independent way.

The foldMemoryOperandImpl hook is going to change in the same way, but I'll wait
until COPY folding is actually implemented. Most targets only fold copies and
won't need to specialize this hook at all.

llvm-svn: 107991

EXTRACT_SUBREG no longer appears as a machine instruction. Use COPY instead.

Add isCopy() checks in many places using isMoveInstr() and isExtractSubreg().
The isMoveInstr hook will be removed later.

llvm-svn: 107879