Commit Graph

6426 Commits

Author SHA1 Message Date
Chris Lattner
e471d94f91 fix a crash in loop unswitch on a loop invariant vector condition.
llvm-svn: 95055
2010-02-02 02:26:54 +00:00
Dan Gohman
95e0161d1b LangRef.html says that inttoptr and ptrtoint always use zero-extension
when the cast is extending.

llvm-svn: 95046
2010-02-02 01:44:02 +00:00
Eric Christopher
02559754dc Don't need to check the last argument since it'll always be bool. We also
don't use TargetData here.

llvm-svn: 95040
2010-02-02 00:51:45 +00:00
Eric Christopher
48f2aae32f More indentation/tabification fixes.
llvm-svn: 95036
2010-02-02 00:13:06 +00:00
Eric Christopher
1004836336 Untabify previous commit.
llvm-svn: 95035
2010-02-02 00:06:55 +00:00
Eric Christopher
9e9e599070 Formatting.
llvm-svn: 95027
2010-02-01 23:25:03 +00:00
Bob Wilson
1f966e8ca6 Add an option to GVN to remove all partially redundant loads. This is currently
disabled by default.  This divides the existing load PRE code into 2 phases:
first it checks that it is safe to move the load to each of the predecessors
where it is unavailable, and then if it is safe, the code is changed to move
the load.  Radar 7571861.

llvm-svn: 95007
2010-02-01 21:17:14 +00:00
Chris Lattner
333bf5abf5 cleanups.
llvm-svn: 94995
2010-02-01 19:54:45 +00:00
Chris Lattner
5f10919836 fix rdar://7590304, a miscompilation of objc apps on arm. The caller
of objc message send was getting marked arm_apcscc, but the prototype
isn't.  This is fine at runtime because objcmsgsend is implemented in
assembly.  Only turn a mismatched caller and callee into 'unreachable'
if the callee is a definition.

llvm-svn: 94986
2010-02-01 18:11:34 +00:00
Chris Lattner
a336497d3f fix rdar://7590304, an infinite loop in instcombine. In the invoke
case, instcombine can't zap the invoke for fear of changing the CFG.
However, we have to do something to prevent the next iteration of
instcombine from inserting another store -> undef before the invoke
thereby getting into infinite iteration between dead store elim and
store insertion.

Just zap the callee to null, which will prevent the next iteration
from doing anything.

llvm-svn: 94985
2010-02-01 18:04:58 +00:00
Bob Wilson
8207d33d94 Fix pr6198 by moving the isSized() check to an outer conditional.
The testcase from pr6198 does not crash for me -- I don't know what's up with
that -- so I'm not adding it to the tests.

llvm-svn: 94984
2010-02-01 17:41:44 +00:00
Eli Friedman
19c5c57885 Simplify/generalize the xor+add->sign-extend instcombine.
llvm-svn: 94943
2010-01-31 04:29:12 +00:00
Eli Friedman
58c7936637 Add a small transform: transform -(X<<Y) to (-X<<Y) when the shift has a single
use and X is free to negate.

llvm-svn: 94941
2010-01-31 02:30:23 +00:00
Evan Cheng
c2f3c20680 Do not mark no-return calls tail calls. It'll screw up special calls like longjmp and it doesn't make much sense for performance reason. If my logic is faulty, please let me know.
llvm-svn: 94937
2010-01-31 00:59:31 +00:00
Bob Wilson
0f04082970 Check alignment of loads when deciding whether it is safe to execute them
unconditionally.  Besides checking the offset, also check that the underlying
object is aligned as much as the load itself.

llvm-svn: 94875
2010-01-30 04:42:39 +00:00
Bob Wilson
e979c978e0 Use more specific types to avoid casts. No functionality change.
llvm-svn: 94863
2010-01-30 00:41:10 +00:00
Jakob Stoklund Olesen
e3fd8b5848 Keep iterating over all uses when meeting a phi node in AllUsesOfValueWillTrapIfNull().
This bug was exposed by my inliner cost changes in r94615, and caused failures
of lencod on most architectures when building with LTO.

This patch fixes lencod and 464.h264ref on x86-64 (and likely others).

llvm-svn: 94858
2010-01-29 23:54:14 +00:00
Bob Wilson
71bc5f0787 Preserve load alignment in instcombine transformations. I've been unable to
create a testcase where this matters.  The select+load transformation only
occurs when isSafeToLoadUnconditionally is true, and in those situations,
instcombine also changes the underlying objects to be aligned.  This seems
like a good idea regardless, and I've verified that it doesn't pessimize
the subsequent realignment.

llvm-svn: 94850
2010-01-29 22:39:21 +00:00
Eric Christopher
47d90f7adb Revert my last couple of patches. They appear to have broken bison.
llvm-svn: 94841
2010-01-29 21:16:24 +00:00
Bob Wilson
bb651db10d Use uint64_t instead of unsigned for offsets and sizes.
llvm-svn: 94835
2010-01-29 20:34:28 +00:00
Bob Wilson
f897b7b37e Improve isSafeToLoadUnconditionally to recognize that GEPs with constant
indices are safe if the result is known to be within the bounds of the
underlying object.

llvm-svn: 94829
2010-01-29 19:19:08 +00:00
Duncan Sands
d6baca9159 Having RHSKnownZero and RHSKnownOne be alternative names for KnownZero and KnownOne
(via APInt &RHSKnownZero = KnownZero, etc) seems dangerous and confusing to me: it
is easy not to notice this, and then wonder why KnownZero/RHSKnownZero changed
underneath you when you modified RHSKnownZero/KnownZero etc.  So get rid of this.
No intended functionality change (tested with "make check" + llvm-gcc bootstrap).

llvm-svn: 94802
2010-01-29 06:18:46 +00:00
Eric Christopher
f01379e6c2 Make strcpy_chk lower to strcpy if we have a safe size.
llvm-svn: 94783
2010-01-29 01:37:11 +00:00
Eric Christopher
7d74af1824 Add constant support to object size handling and remove default
lowering. We'll either figure it out, or not and be lowered by
SelectionDAGBuild.

Add test.

llvm-svn: 94775
2010-01-29 01:09:57 +00:00
Bill Wendling
f6736d2bae Generic reformatting and comment fixing. No functionality change.
llvm-svn: 94771
2010-01-29 00:52:43 +00:00
Bill Wendling
d115615285 Add newline to debugging output, and fix some grammar-os in comment.
llvm-svn: 94765
2010-01-29 00:27:39 +00:00
Victor Hernandez
60060d030c mem2reg erases the dbg.declare intrinsics that it converts to dbg.val intrinsics
llvm-svn: 94763
2010-01-29 00:01:35 +00:00
Duncan Sands
a3395c61b5 Fix PR6165. The bug was that LHSKnownZero was being and'd with DemandedMask
when it should have been and'd with LowBits.  Fix that and while there beef
up the logic in the case of a negative LHS.

llvm-svn: 94745
2010-01-28 17:22:42 +00:00
Bob Wilson
2e1a609654 Avoid creating redundant PHIs in SSAUpdater::GetValueInMiddleOfBlock.
This was already being done in SSAUpdater::GetValueAtEndOfBlock so I've
just changed SSAUpdater to check for existing PHIs in both places.

llvm-svn: 94690
2010-01-27 22:01:02 +00:00
Jeffrey Yasskin
fb10587e50 Kill ModuleProvider and ghost linkage by inverting the relationship between
Modules and ModuleProviders. Because the "ModuleProvider" simply materializes
GlobalValues now, and doesn't provide modules, it's renamed to
"GVMaterializer". Code that used to need a ModuleProvider to materialize
Functions can now materialize the Functions directly. Functions no longer use a
magic linkage to record that they're materializable; they simply ask the
GVMaterializer.

Because the C ABI must never change, we can't remove LLVMModuleProviderRef or
the functions that refer to it. Instead, because Module now exposes the same
functionality ModuleProvider used to, we store a Module* in any
LLVMModuleProviderRef and translate in the wrapper methods.  The bindings to
other languages still use the ModuleProvider concept.  It would probably be
worth some time to update them to follow the C++ more closely, but I don't
intend to do it.

Fixes http://llvm.org/PR5737 and http://llvm.org/PR5735.

llvm-svn: 94686
2010-01-27 20:34:15 +00:00
Benjamin Kramer
cfe07fadc7 Don't bother with sprintf, just pass the Twine through.
llvm-svn: 94684
2010-01-27 19:58:47 +00:00
Benjamin Kramer
d408373dbe Use the less expensive getName function instead of getNameStr.
llvm-svn: 94683
2010-01-27 19:46:52 +00:00
Chris Lattner
deabd1cfb6 some cleanups.
llvm-svn: 94649
2010-01-27 02:12:20 +00:00
Chris Lattner
354782f9b9 no need to check for null
llvm-svn: 94648
2010-01-27 02:04:20 +00:00
Victor Hernandez
e6321dc910 When converting dbg.declare to dbg.value, attach promoted store's debug metadata to dbg.value
llvm-svn: 94634
2010-01-27 00:44:36 +00:00
Victor Hernandez
4e7937f77b Avoid extra calls to MD->getNumOperands()
llvm-svn: 94618
2010-01-26 23:29:09 +00:00
Victor Hernandez
3a9845ecf7 Switch AllocaDbgDeclares to SmallVector and don't leak DIFactory
llvm-svn: 94567
2010-01-26 18:57:53 +00:00
Victor Hernandez
f12e8a120f In mem2reg, for all alloca/stores that get promoted where the alloca has an associated llvm.dbg.declare instrinsic, insert an llvm.dbg.var intrinsic before each store.
llvm-svn: 94493
2010-01-26 02:42:15 +00:00
Bob Wilson
e3d00b2e56 Remove check for an impossible condition: the condition of the while loop has
already checked that TmpBB->getSinglePredecessor() is non-null.

llvm-svn: 94451
2010-01-25 21:28:05 +00:00
Bob Wilson
1882fba746 Change Value::getUnderlyingObject to have the MaxLookup value specified as a
parameter with a default value, instead of just hardcoding it in the
implementation.  The limit of MaxLookup = 6 was introduced in r69151 to fix
a performance problem with O(n^2) behavior in instcombine, but the scalarrepl
pass is relying on getUnderlyingObject to go all the way back to an AllocaInst.
Making the limit part of the method signature makes it clear that by default
the result is limited and should help avoid similar problems in the future.
This fixes pr6126.

llvm-svn: 94433
2010-01-25 18:26:54 +00:00
Victor Hernandez
253c09eb8f Revert r94260 until findDbgDeclare() is made more efficient
llvm-svn: 94432
2010-01-25 17:52:13 +00:00
Chris Lattner
5a57121631 make -fno-rtti the default unless a directory builds with REQUIRES_RTTI.
llvm-svn: 94378
2010-01-24 20:43:08 +00:00
Chris Lattner
91fafbd4e8 change the canonical form of "cond ? -1 : 0" to be
"sext cond" instead of a select.  This simplifies some instcombine
code, matches the policy for zext (cond ? 1 : 0 -> zext), and allows
us to generate better code for a testcase on ppc.

llvm-svn: 94339
2010-01-24 00:09:49 +00:00
Chris Lattner
b9e618553f fix a potential overflow issue Eli pointed out.
llvm-svn: 94336
2010-01-23 23:31:46 +00:00
Nick Lewycky
f9a681fb61 Speculatively revert r94322 to see if it fixes darwin selfhost buildbot.
llvm-svn: 94331
2010-01-23 20:32:12 +00:00
Chris Lattner
b444bc0234 third bug from PR6119: the xor dupe extension allows
for arbitrary terminators in predecessors, don't assume
it is a conditional or uncond branch.  The testcase shows
an example where they can happen with switches.

llvm-svn: 94323
2010-01-23 19:21:31 +00:00
Nick Lewycky
8bbb754c7c Teach DAE that even though it can't modify the function signature of an
externally visible function, it can still find all callers of it and replace
the parameters to a dead argument with undef.

llvm-svn: 94322
2010-01-23 19:19:34 +00:00
Chris Lattner
7130788ea2 add an early out to ProcessBranchOnXOR to speed it up,
handle the case when we can infer an input to the xor
from all inputs that agree, instead of going into an
infinite loop.  Another part of PR6199

llvm-svn: 94321
2010-01-23 19:16:25 +00:00
Chris Lattner
e4391a1adb fix a crash in jump threading, PR6119
llvm-svn: 94319
2010-01-23 18:56:07 +00:00
Chris Lattner
8909d5aca5 implement a simple instcombine xform that has been in the
readme forever.

llvm-svn: 94318
2010-01-23 18:49:30 +00:00
Eric Christopher
bc8f2b1a56 Reapply 94059 while fixing the calling convention setup
for strcpy.

llvm-svn: 94287
2010-01-23 05:29:06 +00:00
Victor Hernandez
7ce9006ba0 In mem2reg, for all alloca/stores that get promoted where the alloca has an associated llvm.dbg.declare instrinsic, insert an llvm.dbg.var intrinsic before each store
llvm-svn: 94260
2010-01-23 00:17:34 +00:00
Benjamin Kramer
a56f170cc0 Another strncmp -> StringRef.startswith simplification.
llvm-svn: 94203
2010-01-22 20:00:21 +00:00
Bob Wilson
8d14b72877 Revert 94059. It is breaking the MultiSource/Benchmarks/Prolangs-C/bison
test on ARM.

llvm-svn: 94198
2010-01-22 19:16:40 +00:00
Victor Hernandez
e4d8ef8fc4 Keep ignoring pointer-to-pointer bitcasts
llvm-svn: 94194
2010-01-22 19:05:05 +00:00
Chris Lattner
276811b58a Stop building RTTI information for *most* llvm libraries. Notable
missing ones are libsupport, libsystem and libvmcore.  libvmcore is
currently blocked on bugpoint, which uses EH.  Once it stops using
EH, we can switch it off.

This #if 0's out 3 unit tests, because gtest requires RTTI information.
Suggestions welcome on how to fix this.

llvm-svn: 94164
2010-01-22 06:49:46 +00:00
Dan Gohman
525f7d7833 Revert LoopStrengthReduce.cpp to pre-r94061 for now.
llvm-svn: 94123
2010-01-22 00:46:49 +00:00
Victor Hernandez
728ab49966 No need to look through bitcasts for DbgInfoIntrinsic
llvm-svn: 94114
2010-01-21 23:09:12 +00:00
Victor Hernandez
ef9e66c909 DbgInfoIntrinsic no longer appear in an instruction's use list
llvm-svn: 94113
2010-01-21 23:08:36 +00:00
Victor Hernandez
1cc721ee56 No need to look through bitcasts for DbgInfoIntrinsic
llvm-svn: 94112
2010-01-21 23:07:15 +00:00
Victor Hernandez
d44671b931 DbgInfoIntrinsics no longer appear in an instruction's use list; so clean up looking for them in use iterations and remove OnlyUsedByDbgInfoIntrinsics()
llvm-svn: 94111
2010-01-21 23:05:53 +00:00
Dan Gohman
23ac1f6157 When inserting expressions for post-increment users which contain
loop-variant components, adds must be inserted after the increment.
Keep track of the increment position for this case, and insert
these adds in the correct location.

llvm-svn: 94110
2010-01-21 23:01:22 +00:00
Dan Gohman
2c93a3fa96 Include IVUsers information in LSR's debug output.
llvm-svn: 94108
2010-01-21 22:46:32 +00:00
Dan Gohman
3cce294b13 Prune the search for candidate formulae if the number of register
operands exceeds the number of registers used in the initial
solution, as that wouldn't lead to a profitable solution anyway.

llvm-svn: 94107
2010-01-21 22:42:49 +00:00
Dan Gohman
a4954135a7 Add a comment.
llvm-svn: 94104
2010-01-21 21:31:09 +00:00
Chris Lattner
642049e127 It turns out that this #include is needed because otherwise
ValueMapper.cpp ends up calling an out of line 
__ZNK4llvm12PATypeHolder3getEv, which is a template and llvm-config
determines arbitrarily to use the one in libipo.  This sucks, but
keeping the #include is a reasonable workaround.

llvm-svn: 94103
2010-01-21 21:29:25 +00:00
Chris Lattner
3547371b0b unbreak the build, apparently without this transformutils starts depending on libipa?
llvm-svn: 94102
2010-01-21 21:20:51 +00:00
Chris Lattner
3f91babac8 tidy up
llvm-svn: 94101
2010-01-21 21:05:54 +00:00
Victor Hernandez
507d86fcbb Don't need to include IntrinsicInst.h any more
llvm-svn: 94092
2010-01-21 19:33:59 +00:00
Victor Hernandez
3a31114cf9 No need to map NULL operands of metadata
llvm-svn: 94091
2010-01-21 19:26:20 +00:00
Dan Gohman
be34c35f32 Re-implement the main strength-reduction portion of LoopStrengthReduction.
This new version is much more aggressive about doing "full" reduction in
cases where it reduces register pressure, and also more aggressive about
rewriting induction variables to count down (or up) to zero when doing so
reduces register pressure.

It currently uses fairly simplistic algorithms for finding reuse
opportunities, but it introduces a new framework allows it to combine
multiple strategies at once to form hybrid solutions, instead of doing
all full-reduction or all base+index.

llvm-svn: 94061
2010-01-21 02:09:26 +00:00
Eric Christopher
939ad8be86 Add strcpy_chk -> strcpy support for "don't know" object size
answers.  This will update as object size checking gets better information.

llvm-svn: 94059
2010-01-21 01:04:38 +00:00
Chris Lattner
5c16b9815b simplify this code.
llvm-svn: 94048
2010-01-20 23:30:28 +00:00
Jakob Stoklund Olesen
ac14f3bf31 Move per-function inline threshold calculation to a method.
No functional change except the forgotten test for
InlineLimit.getNumOccurrences() == 0 in the CurrentThreshold2 calculation.

llvm-svn: 94007
2010-01-20 17:51:28 +00:00
Victor Hernandez
50e7dcdcc2 Switch Elts from vector to SmallVector
llvm-svn: 93989
2010-01-20 06:56:16 +00:00
Victor Hernandez
d79e7e0e12 Map operands of all function-local metadata, not just metadata passed to llvm.dbg.declare intrinsics
llvm-svn: 93979
2010-01-20 05:49:59 +00:00
Dan Gohman
4ca37472ec When doing address-mode sinking, expand the base register first, rather
than the scaled register. This makes it more likely that subsequent
AddrModeMatcher queries will match the new address the same way as the
old, instead of accidentally matching what had been the base register
as the new scaled register, and then failing to match the scaled register.
This fixes some problems with address-mode sinking multiple muls into a
block, which will be a lot more common with some upcoming
LoopStrengthReduction changes.

llvm-svn: 93935
2010-01-19 22:45:06 +00:00
Chris Lattner
e0124f19f9 optimize ~(~X >>s Y) --> (X >>s Y), patch by Edmund Grimley
Evans!

llvm-svn: 93884
2010-01-19 18:16:19 +00:00
Bob Wilson
e94d77854f Fix a crash in scalarrepl for memcpy/memmove where the source and destination
are the same.  I had already fixed a similar problem where the source and
destination were different bitcasts derived from the same alloca, but the
previous fix still did not handle the case where both operands are exactly
the same value.  Radar 7552893.

llvm-svn: 93848
2010-01-19 04:32:48 +00:00
Eric Christopher
5b602f9bf7 Fix comment.
llvm-svn: 93831
2010-01-19 01:20:15 +00:00
Chris Lattner
6cd7a81f86 my instcombine transformations to make extension elimination more
aggressive changed the canonical form from sext(trunc(x)) to ashr(lshr(x)),
make sure to transform a couple more things into that canonical form,
and catch a case where we missed turning zext/shl/ashr into a single sext.

llvm-svn: 93787
2010-01-18 22:19:16 +00:00
Devang Patel
2cae5754c6 While mapping llvm.dbg.declare intrinsic manually map its operand, if possible,
because it points to an alloca instruction through metadata.

llvm-svn: 93757
2010-01-18 19:52:14 +00:00
Owen Anderson
d73ce407a5 Convert some of the dynamic opcode lookups into static ones.
llvm-svn: 93693
2010-01-17 19:33:27 +00:00
Owen Anderson
50cacaff8f Fix comment.
llvm-svn: 93679
2010-01-17 06:49:03 +00:00
Bob Wilson
bdd9890c7d Fix a comment typo.
llvm-svn: 93560
2010-01-15 21:55:02 +00:00
Bill Wendling
488a7187b4 When the visitSub method was split into visitSub and visitFSub, this xform was
added to the FSub version. However, the original version of this xform guarded
against doing this for floating point (!Op0->getType()->isFPOrFPVector()).

This is causing LLVM to perform incorrect xforms for code like:

void func(double *rhi, double *rlo, double xh, double xl, double yh, double yl){
  double mh, ml;
  double c = 134217729.0;
  double up, u1, u2, vp, v1, v2;
        
  up = xh*c;
  u1 = (xh - up) + up;
  u2 = xh - u1;
        
  vp = yh*c;
  v1 = (yh - vp) + vp;
  v2 = yh - v1;
        
  mh = xh*yh;
  ml = (((u1*v1 - mh) + (u1*v2)) + (u2*v1)) + (u2*v2);
  ml += xh*yl + xl*yh;
        
  *rhi = mh + ml;
  *rlo = (mh - (*rhi)) + ml;
}

The last line was optimized away, but rl is intended to be the difference
between the infinitely precise result of mh + ml and after it has been rounded
to double precision.

llvm-svn: 93369
2010-01-13 23:23:17 +00:00
Chris Lattner
21bbaf49d5 1) Use the new SimplifyInstructionsInBlock routine instead of the copy
in JT.

2) When cloning blocks for PHI or xor conditions, use
instsimplify to simplify the code as we go.  This allows us to 
squish common cases early in JT which opens up opportunities for
subsequent iterations, and allows it to completely simplify the
testcase.

llvm-svn: 93253
2010-01-12 20:41:47 +00:00
Chris Lattner
87f86498c3 add a helper function.
llvm-svn: 93251
2010-01-12 19:40:54 +00:00
Chris Lattner
bc0016437d tidy up
llvm-svn: 93222
2010-01-12 02:07:50 +00:00
Chris Lattner
774e3967ad Teach jump threading to duplicate small blocks when the branch
condition is a xor with a phi node.  This eliminates nonsense
like this from 176.gcc in several places:

 LBB166_84:
        testl   %eax, %eax
-       setne   %al
-       xorb    %cl, %al
-       notb    %al
-       testb   $1, %al
-       je      LBB166_85
+       je      LBB166_69
+       jmp     LBB166_85

This is rdar://7391699

llvm-svn: 93221
2010-01-12 02:07:17 +00:00
Chris Lattner
d6d8cc7b37 some cleanup, and make it obvious that ProcessJumpOnPHI only works
on branches by renaming it and checking for a branch at the call site.

llvm-svn: 93208
2010-01-11 23:41:09 +00:00
Chris Lattner
a8cabeeecb reenable the piece that turns trunc(zext(x)) -> x even if zext has multiple uses,
codegen has no apparent problem with the trunc version of this, because it turns
into a simple subreg idiom

llvm-svn: 93202
2010-01-11 22:49:40 +00:00
Chris Lattner
2749cc2036 Disable folding sext(trunc(x)) -> x (and other similar cast/cast cases) when the
trunc has multiple uses.  Codegen is not able to coalesce the subreg case 
correctly and so this leads to higher register pressure and spilling (see PR5997).

This speeds up 256.bzip2 from 8.60 -> 8.04s on my machine, ~7%.

llvm-svn: 93200
2010-01-11 22:45:25 +00:00
Chris Lattner
85a6f02b94 add one more bitfield optimization, allowing clang to generate
good code on PR4216:

_test_bitfield:                                             ## @test_bitfield
	orl	$32962, %edi
	movl	$4294941946, %eax
	andq	%rdi, %rax
	ret

instead of:

_test_bitfield:
        movl    $4294941696, %ecx
        movl    %edi, %eax
        orl     $194, %edi
        orl     $32768, %eax
        andq    $250, %rdi
        andq    %rax, %rcx
        movq    %rdi, %rax
        orq     %rcx, %rax
        ret

Evan is looking into the remaining andq+imm -> andl optimization.

llvm-svn: 93147
2010-01-11 06:55:24 +00:00
Chris Lattner
16e36659f5 Extend CanEvaluateZExtd to handle and/or/xor more aggressively in the
BitsToClear case.  This allows it to promote expressions which have an
and/or/xor after the lshr, promoting cases like test2 (from PR4216) 
and test3 (random extample extracted from a spec benchmark).

clang now compiles the code in PR4216 into:

_test_bitfield:                                             ## @test_bitfield
	movl	%edi, %eax
	orl	$194, %eax
	movl	$4294902010, %ecx
	andq	%rax, %rcx
	orl	$32768, %edi
	andq	$39936, %rdi
	movq	%rdi, %rax
	orq	%rcx, %rax
	ret

instead of:

_test_bitfield:                                             ## @test_bitfield
	movl	%edi, %eax
	orl	$194, %eax
	movl	$4294902010, %ecx
	andq	%rax, %rcx
	shrl	$8, %edi
	orl	$128, %edi
	shlq	$8, %rdi
	andq	$39936, %rdi
	movq	%rdi, %rax
	orq	%rcx, %rax
	ret

which is still not great, but is progress.

llvm-svn: 93145
2010-01-11 04:05:13 +00:00
Chris Lattner
f2ba85eedc Remove the dead TD argument to CanEvaluateZExtd, and add a
new BitsToClear result which allows us to start promoting
expressions that end with a lshr-by-constant.  This is
conservatively correct and better than what we had before
(see testcases) but still needs to be extended further.

llvm-svn: 93144
2010-01-11 03:32:00 +00:00
Chris Lattner
d7f1b97147 improve comments, remove dead TD argument to CanEvaluateSExtd.
llvm-svn: 93143
2010-01-11 02:43:35 +00:00
Chris Lattner
18d753e05f teach sext optimization to handle truncs from types that are not
the dest of the sext.

llvm-svn: 93128
2010-01-10 20:30:41 +00:00
Chris Lattner
ca53de1ab7 teach zext optimization how to deal with truncs that don't come from
the zext dest type.  This allows us to handle test52/53 in cast.ll,
and allows llvm-gcc to generate much better code for PR4216 in -m64
mode:

_test_bitfield:                                             ## @test_bitfield
	orl	$32962, %edi
	movl	%edi, %eax
	andl	$-25350, %eax
	ret

This also fixes a bug handling vector extends, ensuring that the
mask produced is a vector constant, not an integer constant.

llvm-svn: 93127
2010-01-10 20:25:54 +00:00
Chris Lattner
67e0ef4d5d simplify CanEvaluateSExtd to return a bool now that we have a
simpler profitability predicate.

llvm-svn: 93111
2010-01-10 07:57:20 +00:00