heuristic to reshuffle register assignments when we can't find an
available reg.

llvm-svn: 121388

llvm-svn: 121356

references instead.

Similarly, IntervalMap::begin() is almost as expensive as find(), so use find(x)
instead of begin().advanceTo(x);

This makes RegAllocBasic run another 5% faster.

llvm-svn: 121344

This fixes radar 8730409.

llvm-svn: 121323

llvm-svn: 121319

The hint is simply tried first and then forgotten if it couldn't be allocated
immediately.

llvm-svn: 121306

abstract priority queue interface in subclasses that want to override the
priority calculations.

Subclasses must provide a getPriority() implementation instead.

This approach requires less code as long as priorities are expressable as simple
floats, and it avoids the dangers of defining potentially expensive priority
comparison functions.

It also should speed up priority_queue operations since they no longer have to
chase pointers when comparing registers. This is not measurable, though.

Preferably, we shouldn't use floats to guide code generation. The use of floats
here is derived from the use of floats for spill weights. Spill weights have a
dynamic range that doesn't lend itself easily to a fixpoint implementation.

When someone invents a stable spill weight representation, it can be reused for
allocation priorities.

llvm-svn: 121294

llvm-svn: 121293

llvm-svn: 121285

llvm-svn: 121283

both forward and backward scheduling. Rename it to
ScoreboardHazardRecognizer (Scoreboard is one word). Remove integer
division from the scoreboard's critical path.

llvm-svn: 121274

This new register allocator is initially identical to RegAllocBasic, but it will
receive all of the tricks that RegAllocBasic won't get.

RegAllocGreedy will eventually replace linear scan.

llvm-svn: 121234

Minor optimization to the use of IntervalMap iterators. They are fairly
heavyweight, so prefer SI.valid() over SI != end().

llvm-svn: 121217

This speeds up RegAllocBasic by 20%, not counting releaseMemory which becomes
way faster.

llvm-svn: 121201

llvm-svn: 121162

zextOrTrunc(), and APSInt methods extend(), extOrTrunc() and new method
trunc(), to be const and to return a new value instead of modifying the
object in place.

llvm-svn: 121120

llvm-svn: 121098

This will be used to truncate live range of DBG_VALUE instruction by register allocator and friends.

llvm-svn: 121061

If dbg_declare() or dbg_value() is not lowered by isel then emit DEBUG message instead of creating DBG_VALUE for undefined value in reg0.

llvm-svn: 121059

as llc + llvm-mc. This time ELF is not changed and I tested that llvm-gcc
bootstrap on darwin10 using darwin9's assembler and linker.

llvm-svn: 121006

linux and darwin assemblers happy :-(

llvm-svn: 121004

that no relocations are used (on MochO).
Fixes llc producing different output from llc + llvm-mc.

llvm-svn: 121000

StrongPHIElimination.

llvm-svn: 120961

llvm-svn: 120959

PHIElimination.h.

llvm-svn: 120953

time, this method existed, but now PHIElimination uses the method of the same
name on MachineBasicBlock.

llvm-svn: 120952

function so that it can be shared with StrongPHIElimination.

llvm-svn: 120951

llvm-svn: 120918

llvm-svn: 120910

llvm-svn: 120846

be emitted.

llvm-svn: 120845

llvm-svn: 120842

llvm-svn: 120841

The StrongPHIElimination pass did not work, and nobody has worked on it for two
years.

A rewrite is underway, so I am leaving this shell pass instead of deleting it
completely.

llvm-svn: 120830

llvm-svn: 120720

Scan the MachineFunction for DBG_VALUE instructions, and replace them with a
data structure similar to LiveIntervals. The live range of a DBG_VALUE is
determined by propagating it down the dominator tree until a new DBG_VALUE is
found. When a DBG_VALUE lives in a register, its live range is confined to the
live range of the register's value.

LiveDebugVariables runs before coalescing, so DBG_VALUEs are not artificially
extended when registers are joined.

The missing half will recreate DBG_VALUE instructions from the intervals when
register allocation is complete.

The pass is disabled by default. It can be enabled with the temporary command
line option -live-debug-variables.

llvm-svn: 120636

setAllBits(), setBit(unsigned), etc.

llvm-svn: 120564

llvm-svn: 120504

legalization time. Since at legalization time there is no mapping from
SDNode back to the corresponding LLVM instruction and the return
SDNode is target specific, this requires a target hook to check for
eligibility. Only x86 and ARM support this form of sibcall optimization
right now.
rdar://8707777

llvm-svn: 120501

in favor of the widespread llvm style. Capitalize variables and add
newlines for visual parsing. Rename variables for readability.
And other cleanup.

llvm-svn: 120490