This doesn't kick in too much because of phi translation issues,
but this can be resolved in the future.

llvm-svn: 82447

llvm-svn: 82446

llvm-svn: 82444

analysis, one that does the xform.

llvm-svn: 82443

from a piece of a large store when both are in the same block.

This allows clang to compile the testcase in PR4216 to this code:

_test_bitfield:
	movl	4(%esp), %eax
	movl	%eax, %ecx
	andl	$-65536, %ecx
	orl	$32962, %eax
	andl	$40186, %eax
	orl	%ecx, %eax
	ret

This is not ideal, but is a whole lot better than the code produced
by llvm-gcc:

_test_bitfield:
	movw	$-32574, %ax
	orw	4(%esp), %ax
	andw	$-25350, %ax
	movw	%ax, 4(%esp)
	movw	7(%esp), %cx
	shlw	$8, %cx
	movzbl	6(%esp), %edx
	orw	%cx, %dx
	movzwl	%dx, %ecx
	shll	$16, %ecx
	movzwl	%ax, %eax
	orl	%ecx, %eax
	ret

and dramatically better than that produced by gcc 4.2:

_test_bitfield:
	pushl	%ebx
	call	L3
"L00000000001$pb":
L3:
	popl	%ebx
	movl	8(%esp), %eax
	leal	0(,%eax,4), %edx
	sarb	$7, %dl
	movl	%eax, %ecx
	andl	$7168, %ecx
	andl	$-7201, %ebx
	movzbl	%dl, %edx
	andl	$1, %edx
	sall	$5, %edx
	orl	%ecx, %ebx
	orl	%edx, %ebx
	andl	$24, %eax
	andl	$-58336, %ebx
	orl	%eax, %ebx
	orl	$32962, %ebx
	movl	%ebx, %eax
	popl	%ebx
	ret

llvm-svn: 82439

llvm-svn: 82426

so that nonlocal and partially redundant loads can use it as well.
The testcase shows examples of craziness this can handle.  This triggers
*many* times in 176.gcc.

llvm-svn: 82403

more generic.

llvm-svn: 82402

(and load -> load) when the base pointers must alias but when
they are different types.  This occurs very very frequently in
176.gcc and other code that uses bitfields a lot.

llvm-svn: 82399

llvm-svn: 82355

Reviewed by Dan Gohman.

llvm-svn: 82300

llvm-svn: 82097

constants out of loops. These aren't covered by the regular LICM
pass, because in LLVM IR constants don't require separate
instructions. They're not always covered by the MachineLICM pass
either, because it doesn't know how to unfold folded constant-pool
loads. This is somewhat experimental at this point, and off by
default.

llvm-svn: 82076

phis, similar to the FoldPHIArgGEPIntoPHI change.

Also, delete some comments that don't reflect the code.

llvm-svn: 82053

llvm-svn: 82034

more than one phi, since that leads to higher register pressure on
entry to the phi. This is especially problematic when the phi is in
a loop header, as it increases register pressure throughout the loop.

llvm-svn: 81993

llvm-svn: 81851

llvm-svn: 81840

memset region to the alignment of the new start address.

llvm-svn: 81810

loop exit edge -- new PHIs may be needed not only for the additional
splits that are made to preserve LoopSimplify form, but also for the
original split. Factor out the code that inserts new PHIs so that it
can be used for both. Remove LoopRotation.cpp's code for manually
updating LCSSA form, as it is now redundant. This fixes PR4934.

llvm-svn: 81363

llvm-svn: 81361

llvm-svn: 81354

extractelement(load).

llvm-svn: 81239

that get created during loop unswitching, and fix SplitBlockPredecessors'
LCSSA updating code to create new PHIs instead of trying to just move
existing ones.

Also, optimize Loop::verifyLoop, since it gets called a lot. Use
searches on a sorted list of blocks instead of calling the "contains"
function, as is done in other places in the Loop class, since "contains"
does a linear search. Also, don't call verifyLoop from LoopSimplify or
LCSSA, as the PassManager is already calling verifyLoop as part of
LoopInfo's verifyAnalysis.

llvm-svn: 81221

llvm-svn: 81186

extractelement operations into a bitcast of the pointer,
then a gep, then a scalar load.  Disable this when the vector
only has one element, because it leads to infinite loops in
instcombine (PR4908).

This transformation seems like a really bad idea to me, as it
will likely disable CSE of vector load/stores etc and can be
better done in the code generator when profitable.  This
goes all the way back to the first days of packed types,
r25299 specifically.

I'll let those people who care about the performance of vector
code decide what to do with this.

llvm-svn: 81185

context for the newly created operations.
 
Patch by Jakub Staszak!

llvm-svn: 81175

llvm-svn: 81172

about by icc (#593, partial).  Patch by Erick Tryzelaar.

llvm-svn: 81115

 - I think there are more instances of this, but I think they are fixed in Dan's
   incoming patch. This one was preventing me from doing a bugpoint reduction
   though.

llvm-svn: 81103

llvm-svn: 81101

breaks MiniSAT on x86_64.

llvm-svn: 81098

Constant uniquing tables. This allows distinct ConstantExpr objects
with the same operation and different flags.

Even though a ConstantExpr "a + b" is either always overflowing or
never overflowing (due to being a ConstantExpr), it's still necessary
to be able to represent it both with and without overflow flags at
the same time within the IR, because the safety of the flag may
depend on the context of the use. If the constant really does overflow,
it wouldn't ever be safe to use with the flag set, however the use
may be in code that is never actually executed.

This also makes it possible to merge all the flags tests into a single test.

llvm-svn: 80998

that these passes are properly preserved.

Fix several transformation passes that claimed to preserve LoopSimplify
form but weren't.

llvm-svn: 80926

instead of a bool argument, and to do the dominator check itself.
This makes it eaiser to use when DominatorTree information is
available.

llvm-svn: 80920

memcpy calls.

llvm-svn: 80915

simplifylibcalls optimization is thus valid for C++ but not C.
It's not important enough to worry about for C++ apps, so just
remove it.

rdar://7191924

llvm-svn: 80887

llvm-svn: 80871

re-commit r66920 (which has been backed out in r66953) I may have more luck this time. I'll back out if needed...

llvm-svn: 80858

the instruction BBI points to.

llvm-svn: 80768