only disable it if we don't know it will be obviously profitable.
Still fixme, but less so. :)

llvm-svn: 44658

the X86 backend are needed before this should be enabled by default.

llvm-svn: 44657

_foo:
	movl	$12, %eax
	andl	4(%esp), %eax
	movl	_array(%eax), %eax
	ret

instead of:

_foo:
	movl	4(%esp), %eax
	shrl	$2, %eax
	andl	$3, %eax
	movl	_array(,%eax,4), %eax
	ret

As it turns out, this triggers all the time, in a wide variety of
situations, for example, I see diffs like this in various programs:

-       movl    8(%eax), %eax
-       shll    $2, %eax
-       andl    $1020, %eax
-       movl    (%esi,%eax), %eax
+       movzbl  8(%eax), %eax
+       movl    (%esi,%eax,4), %eax


-       shll    $2, %edx
-       andl    $1020, %edx
-       movl    (%edi,%edx), %edx
+       andl    $255, %edx
+       movl    (%edi,%edx,4), %edx

Unfortunately, I also see stuff like this, which can be fixed in the
X86 backend:

-       andl    $85, %ebx
-       addl    _bit_count(,%ebx,4), %ebp
+       shll    $2, %ebx
+       andl    $340, %ebx
+       addl    _bit_count(%ebx), %ebp

llvm-svn: 44656

llvm-svn: 44654

llvm-svn: 44649

Fix for PR1831: if all defs of an interval are re-materializable, then it's a preferred spill candiate.

llvm-svn: 44644

llvm-svn: 44612

llvm-svn: 44611

llvm-svn: 44610

llvm-svn: 44609

llvm-svn: 44608

llvm-svn: 44607

  This allows an important optimization to be re-enabled.
- If all uses / defs of a split interval can be folded, give the interval a
  low spill weight so it would not be picked in case spilling is needed (avoid
  pushing other intervals in the same BB to be spilled).

llvm-svn: 44601

the stored register is killed.

llvm-svn: 44600

llvm-svn: 44587

Spiller unfold optimization bug: do not clobber a reusable stack slot value unless it can be modified.

llvm-svn: 44575

to codegen this:

define float @test_extract_elt(<1 x float> * %P) {
	%p = load <1 x float>* %P
	%R = extractelement <1 x float> %p, i32 0
	ret float %R
}

llvm-svn: 44570

llvm-svn: 44569

llvm-svn: 44565

llvm-svn: 44549

throw exceptions", just mark intrinsics with the nounwind
attribute.  Likewise, mark intrinsics as readnone/readonly
and get rid of special aliasing logic (which didn't use
anything more than this anyway).

llvm-svn: 44544

llvm-svn: 44532

llvm-svn: 44531

llvm-svn: 44517

llvm-svn: 44482

llvm-svn: 44479

llvm-svn: 44467

llvm-svn: 44446

llvm-svn: 44443

in the middle of a split basic block, create a new live interval starting at
the def. This avoid artifically extending the live interval over a number of
cycles where it is dead. e.g.

bb1:
       = vr1204   (use / kill) <= new interval starts and ends here.
...
...
vr1204 =          (new def)   <= start a new interval here.
       = vr1204   (use)

llvm-svn: 44436

llvm-svn: 44434

llvm-svn: 44428

llvm-svn: 44427

use them.

llvm-svn: 44403

llvm-svn: 44399

llvm-svn: 44386

llvm-svn: 44384

llvm-svn: 44371

the function type, instead they belong to functions
and function calls.  This is an updated and slightly
corrected version of Reid Spencer's original patch.
The only known problem is that auto-upgrading of
bitcode files doesn't seem to work properly (see
test/Bitcode/AutoUpgradeIntrinsics.ll).  Hopefully
a bitcode guru (who might that be? :) ) will fix it.

llvm-svn: 44359

llvm-svn: 44352