llvm-svn: 121741

spill weight. Filter out fixed registers instead.

Add support for reassigning an interference that was assigned to an alias.

llvm-svn: 121737

llvm-svn: 121736

when the wider type is legal.  This allows us to compile:

define zeroext i16 @test1(i16 zeroext %x) nounwind {
entry:
	%div = udiv i16 %x, 33
	ret i16 %div
}

into:

test1:                                  # @test1
	movzwl	4(%esp), %eax
	imull	$63551, %eax, %eax      # imm = 0xF83F
	shrl	$21, %eax
	ret

instead of:

test1:                                  # @test1
        movw    $-1985, %ax             # imm = 0xFFFFFFFFFFFFF83F
        mulw    4(%esp)
        andl    $65504, %edx            # imm = 0xFFE0
        movl    %edx, %eax
        shrl    $5, %eax
        ret

Implementing rdar://8760399 and example #4 from:
http://blog.regehr.org/archives/320

We should implement the same thing for [su]mul_hilo, but I don't
have immediate plans to do this.

llvm-svn: 121696

for each constant pool entry.  Using WriteTypeSymbolic here takes time
proportional to the size of the module, for each constant pool entry.

This speeds up -verbose-asm llc on 252.eon (a random testcase at my disposal)
from 4.4s to 2.137s.  llc takes 2.11s with asm-verbose off, so this is now a
pretty reasonable cost for verbose comments.

llvm-svn: 121691

llvm-svn: 121662

catch this here rather than later after accessing uninitialized memory
etc.  Fires when compiling the testcase in PR8237.

llvm-svn: 121635

llvm-svn: 121604

llvm-svn: 121599

Fix build breakage.

llvm-svn: 121596

lib/CodeGen/RegAllocGreedy.cpp:233: error: unused variable 'TRC' [-Wunused-variable]

llvm-svn: 121594

Soon, RegAllocGreedy will start splitting live ranges, and then deferred
spilling won't work anyway.

llvm-svn: 121591

The spiller should only spill. The register allocator will drive live range
splitting, it has the needed information about register pressure and
interferences.

llvm-svn: 121590

llvm-svn: 121584

interference check.

llvm-svn: 121519

registers for a given virtual register.

Reserved registers are filtered from the allocation order, and any valid hint is
returned as the first suggestion.

For target dependent hints, a number of arcane target hooks are invoked.

llvm-svn: 121497

llvm-svn: 121471

llvm-svn: 121461

f:
        .cfi_startproc
        nop
        .cfi_endproc

assembled (on ELF).

llvm-svn: 121434

Necessary for byval support on ARM.  Radar 7662569.

llvm-svn: 121412

llvm-svn: 121411

llvm-svn: 121410

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