b5ee8b3e89
make truncate/sext elimination capable of changing phi's. This
...
implements rdar://6013816 and the testcase in Transforms/InstCombine/sext-misc.ll.
llvm-svn: 52440
2008-06-18 04:00:49 +00:00
4b50fde2c4
Fix typo that changed the logic to something wrong.
...
Spotted by Nick Lewycky.
llvm-svn: 52411
2008-06-17 15:55:30 +00:00
86cda9e050
Pass around Instruction* instead of Instruction& in FindInsertedValue and friends.
...
llvm-svn: 52318
2008-06-16 13:13:08 +00:00
5cb387735d
80 column fixes.
...
llvm-svn: 52316
2008-06-16 12:57:37 +00:00
e92e18be5a
Move FindScalarValue from InstructionCombining.cpp to ValueTracking.cpp. While
...
I'm at it, rename it to FindInsertedValue.
The only functional change is that newly created instructions are no longer
added to instcombine's worklist, but that is not really necessary anyway (and
I'll commit some improvements next that will completely remove the need).
llvm-svn: 52315
2008-06-16 12:48:21 +00:00
5de0a77a9b
Don't skip over instructions other than loads that might read memory
...
when trying to sink stores.
llvm-svn: 52259
2008-06-13 22:02:12 +00:00
9833a1b407
Make sure SimplifyStoreAtEndOfBlock doesn't mess with loops; the
...
structure checks are incorrect if the blocks aren't distinct.
Fixes PR2435.
llvm-svn: 52257
2008-06-13 21:17:49 +00:00
431e9560b7
fix a minor deviation from the original in my previous commit
...
llvm-svn: 52247
2008-06-12 21:51:29 +00:00
f6d8e77027
op_iterator-ify some loops, low hanging fruit only, there is more
...
llvm-svn: 52246
2008-06-12 21:37:33 +00:00
b2fc72bfbf
Teach instruction combining about the extractvalue. It can succesfully fold
...
useless insert-extract chains, similar to how it folds them for vectors.
Add a testcase for this.
llvm-svn: 52217
2008-06-11 14:05:05 +00:00
3453c7bcb5
Clarify a comment.
...
llvm-svn: 52212
2008-06-11 09:00:12 +00:00
b4866ef30c
Limit the icmp+phi merging optimization to the cases where it is profitable:
...
don't make i1 phis when it won't be possible to eliminate them.
llvm-svn: 52097
2008-06-08 20:52:11 +00:00
1152ca9101
As Chris suggested, handle the situation if ShAmt larger than BitWidth,
...
otherwise, opt might crash.
llvm-svn: 52041
2008-06-06 08:32:05 +00:00
fbe1dc240c
If BitWidth equals to ShtAmt, the RHSKnownZero[BitWidth-ShiftAmt-1] will
...
crash the opt. Just fix this.
Test case in llvm/test/Transforms/InstCombine/2008-06-05-ashr-crash.ll
llvm-svn: 52003
2008-06-05 14:23:44 +00:00
a12a6de683
move CannotBeNegativeZero to ValueTracking. Simplify some signbit comparisons.
...
llvm-svn: 51864
2008-06-02 01:29:46 +00:00
965c769b3c
move ComputeMaskedBits, MaskedValueIsZero, and ComputeNumSignBits
...
out of instcombine into a new file in libanalysis. This also teaches
ComputeNumSignBits about the number of sign bits in a constantint.
llvm-svn: 51863
2008-06-02 01:18:21 +00:00
0397cd2ec4
When simplifying a call to a bitcast function, tighten up
...
the conditions for performing the transform when only the
function declaration is available: no longer allow turning
i32 into i64 for example. Only allow changing between
pointer types, and between pointer types and integers of
the same size. For return values ptr -> intptr was already
allowed; I added ptr -> ptr and intptr -> ptr while there.
As shown by a recent objc testcase, changing the way
parameters/return values are passed can be fatal when calling
code written in assembler that directly manipulates call
arguments and return values unless the transform has no
impact on the way they are passed at the codegen level.
While it is possible to imagine an ABI that treats integers
of pointer size differently to pointers, I don't think LLVM
supports any so the transform should now be safe while still
being useful.
llvm-svn: 51834
2008-06-01 07:38:42 +00:00
035fe6f716
Peer through sext/zext when looking for not(cmp).
...
llvm-svn: 51819
2008-05-31 19:01:33 +00:00
26b8cd84b3
Add more i1 optimizations. add, sub, mul, s/udiv on i1 are now simplified away.
...
llvm-svn: 51817
2008-05-31 17:59:52 +00:00
df9242a833
Adding i1 is always Xor.
...
llvm-svn: 51816
2008-05-31 17:10:28 +00:00
86ff8536f9
const-ify getOpcode.
...
llvm-svn: 51698
2008-05-29 19:53:46 +00:00
ecdefb5df7
Implement PR2370: memmove(x,x,size) -> noop.
...
llvm-svn: 51636
2008-05-28 05:30:41 +00:00
f6ccd2580c
"ret (constexpr)" can't be folded into a Constant. Add a method to
...
Analysis/ConstantFolding to fold ConstantExpr's, then make instcombine use it
to try to use targetdata to fold constant expressions on void instructions.
Also extend the icmp(inttoptr, inttoptr) folding to handle the case where
int size != ptr size.
llvm-svn: 51559
2008-05-25 20:56:15 +00:00
87a099a057
Fix a serious brain-o. Obviously no-one reviewed my patch :(
...
This fixes PR2359
llvm-svn: 51536
2008-05-24 04:06:28 +00:00
f96e1371e8
Tidy up BasicBlock::getFirstNonPHI, and change a bunch of places to
...
use it instead of duplicating its functionality.
llvm-svn: 51499
2008-05-23 21:05:58 +00:00
f52b23c0eb
Replace some weird usage of UserOp1 introduced in r49492 by a plain if.
...
llvm-svn: 51482
2008-05-23 16:17:48 +00:00
3bf5512d87
Constant integer vectors may also be negated.
...
llvm-svn: 51476
2008-05-23 04:54:45 +00:00
8f3127c5b5
Typo.
...
llvm-svn: 51475
2008-05-23 04:39:38 +00:00
4f3d878507
Revert X + X --> X * 2 optz'n which pessimizes heavily on x86.
...
llvm-svn: 51474
2008-05-23 04:34:58 +00:00
452fb32927
Implement X + X for vectors.
...
llvm-svn: 51472
2008-05-23 04:14:51 +00:00
2ec9a01173
Fix a recently added optimization to not crash on vectors.
...
llvm-svn: 51471
2008-05-23 03:26:47 +00:00
6d5f120c5c
Generalize the new code in instcombine's ComputeNumSignBits for handling
...
and/or to handle more cases (such as this add-sitofp.ll testcase), and
port it to selectiondag's ComputeNumSignBits.
llvm-svn: 51469
2008-05-23 02:28:01 +00:00
53b2698531
Use isSingleValueType instead of isFirstClassType to
...
exclude struct and array types.
llvm-svn: 51467
2008-05-23 01:52:21 +00:00
81ab753b14
Port SelectionDAG's ComputeNumSignBits-using code to instcombine,
...
now that instcombine also has ComputeNumSignBits.
llvm-svn: 51350
2008-05-20 21:01:12 +00:00
7ac943fffd
Teach instcombine 4 new xforms:
...
(add (sext x), cst) --> (sext (add x, cst'))
(add (sext x), (sext y)) --> (sext (add int x, y))
(add double (sitofp x), fpcst) --> (sitofp (add int x, intcst))
(add double (sitofp x), (sitofp y)) --> (sitofp (add int x, y))
This generally reduces conversions. For example MiBench/telecomm-gsm
gets these simplifications:
HACK2: %tmp67.i142.i.i = sext i16 %tmp6.i141.i.i to i32 ; <i32> [#uses=1]
%tmp23.i139.i.i = sext i16 %tmp2.i138.i.i to i32 ; <i32> [#uses=1]
%tmp8.i143.i.i = add i32 %tmp67.i142.i.i, %tmp23.i139.i.i ; <i32> [#uses=3]
HACK2: %tmp67.i121.i.i = sext i16 %tmp6.i120.i.i to i32 ; <i32> [#uses=1]
%tmp23.i118.i.i = sext i16 %tmp2.i117.i.i to i32 ; <i32> [#uses=1]
%tmp8.i122.i.i = add i32 %tmp67.i121.i.i, %tmp23.i118.i.i ; <i32> [#uses=3]
HACK2: %tmp67.i.i190.i = sext i16 %tmp6.i.i189.i to i32 ; <i32> [#uses=1]
%tmp23.i.i187.i = sext i16 %tmp2.i.i186.i to i32 ; <i32> [#uses=1]
%tmp8.i.i191.i = add i32 %tmp67.i.i190.i, %tmp23.i.i187.i ; <i32> [#uses=3]
HACK2: %tmp67.i173.i.i.i = sext i16 %tmp6.i172.i.i.i to i32 ; <i32> [#uses=1]
%tmp23.i170.i.i.i = sext i16 %tmp2.i169.i.i.i to i32 ; <i32> [#uses=1]
%tmp8.i174.i.i.i = add i32 %tmp67.i173.i.i.i, %tmp23.i170.i.i.i ; <i32> [#uses=3]
HACK2: %tmp67.i152.i.i.i = sext i16 %tmp6.i151.i.i.i to i32 ; <i32> [#uses=1]
%tmp23.i149.i.i.i = sext i16 %tmp2.i148.i.i.i to i32 ; <i32> [#uses=1]
%tmp8.i153.i.i.i = add i32 %tmp67.i152.i.i.i, %tmp23.i149.i.i.i ; <i32> [#uses=3]
HACK2: %tmp67.i.i.i.i = sext i16 %tmp6.i.i.i.i to i32 ; <i32> [#uses=1]
%tmp23.i.i5.i.i = sext i16 %tmp2.i.i.i.i to i32 ; <i32> [#uses=1]
%tmp8.i.i7.i.i = add i32 %tmp67.i.i.i.i, %tmp23.i.i5.i.i ; <i32> [#uses=3]
This also fixes a bug in ComputeNumSignBits handling select and
makes it more aggressive with and/or.
llvm-svn: 51302
2008-05-20 05:46:13 +00:00
9c27f96d04
fix two issues Neil noticed, thanks!
...
llvm-svn: 51296
2008-05-20 03:50:52 +00:00
d717761a2b
Make AssociativeOpt static.
...
llvm-svn: 51290
2008-05-20 01:14:05 +00:00
123438cc05
Add a ComputeNumSignBits function for use by instcombine, based on the
...
code in SelectionDAG.
llvm-svn: 51279
2008-05-19 22:14:15 +00:00
b42712288e
switch to Type::getFPMantissaWidth instead of reinventing it.
...
llvm-svn: 51275
2008-05-19 21:17:23 +00:00
ba9acbe6dc
minor cleanups, teach instcombine that sitofp/uitofp cannot
...
produce a negative zero.
llvm-svn: 51272
2008-05-19 20:27:56 +00:00
e35fe0f1c6
convert fptosi(sitofp x) -> x if the fp value has enough bits in its mantissa
...
to accurately represent the integer. This triggers 9 times in 471.omnetpp,
though 8 of those seem to be inlined from the same place.
llvm-svn: 51271
2008-05-19 20:25:04 +00:00
5920a78034
Fold FP comparisons where one operand is converted from an integer
...
type and the other operand is a constant into integer comparisons.
This happens surprisingly frequently (e.g. 10 times in 471.omnetpp),
which are things like this:
%tmp8283 = sitofp i32 %tmp82 to double
%tmp1013 = fcmp ult double %tmp8283, 0.0
Clearly comparing tmp82 against i32 0 is cheaper here.
this also triggers 8 times in gobmk, including this one:
%tmp375376 = sitofp i32 %tmp375 to double
%tmp377 = fcmp ogt double %tmp375376, 8.150000e+01
which is comparing an integer against 81.5 :).
llvm-svn: 51268
2008-05-19 20:18:56 +00:00
6e70830af9
remove debug output
...
llvm-svn: 51264
2008-05-19 20:03:53 +00:00
fc365b60dc
be more aggressive about transforming add -> or when the operands have no
...
intersecting bits. This triggers all over the place, for example in lencode,
with adds of stuff like:
%tmp580 = mul i32 %tmp579, 2
%tmp582 = and i32 %b8, 1
and
%tmp28 = shl i32 %abs.i, 1
%sign.0 = select i1 %tmp23, i32 1, i32 0
and
%tmp344 = shl i32 %tmp343, 2
%tmp346 = and i32 %tmp96, 3
etc.
llvm-svn: 51263
2008-05-19 20:01:56 +00:00
4b2a724fb8
Fix PR2339
...
llvm-svn: 51226
2008-05-18 04:11:26 +00:00
79376f4e02
Move isTrueWhenEqual to ICmpInst.
...
llvm-svn: 51215
2008-05-17 07:33:39 +00:00
e1f6e4b21d
API change for {BinaryOperator|CmpInst|CastInst}::create*() --> Create. Legacy interfaces will be in place for some time. (Merge from use-diet branch.)
...
llvm-svn: 51200
2008-05-16 19:29:10 +00:00
5c953b7d27
implement PR2328.
...
llvm-svn: 51176
2008-05-16 02:59:42 +00:00
697e94cc22
Fix a bunch of 80col violations that arose from the Create API change. Tweak makefile targets to find these better.
...
llvm-svn: 51143
2008-05-15 10:04:30 +00:00
3716952f10
Situations can arise when you have a function called that returns a 'void', but
...
is bitcast to return a floating point value. The result of the instruction may
not be used by the program afterwards, and LLVM will happily remove all
instructions except the call. But, on some platforms, if a value is returned as
a floating point, it may need to be removed from the stack (like x87). Thus, we
can't get rid of the bitcast even if there isn't a use of the value.
llvm-svn: 51134
2008-05-14 22:45:20 +00:00
d78c400b5b
Clean up the use of static and anonymous namespaces. This turned up
...
several things that were neither in an anonymous namespace nor static
but not intended to be global.
llvm-svn: 51017
2008-05-13 00:00:25 +00:00
a4ee1f516f
don't sink invokes, even if they are readonly. This fixes a
...
crash on kimwitu++.
llvm-svn: 50901
2008-05-09 15:07:33 +00:00
aaba10e843
Implement PR2298. This transforms:
...
~x < ~y --> y < x
-x == -y --> x == y
llvm-svn: 50882
2008-05-09 05:19:28 +00:00
49a594e6ab
More than just loads can read from memory: readonly calls like strlen
...
also need to be checked for memory modifying instructions before we
can sink them. THis fixes the second half of PR2297.
llvm-svn: 50860
2008-05-08 17:37:37 +00:00
4fa09669d8
Make instcombine's DSE respect loads as well as stores. It is not safe to
...
delete the first store in:
store x -> p
load p
store y -> p
This is for PR2297.
llvm-svn: 50859
2008-05-08 17:20:30 +00:00
fc2edad4ae
Turn StripPointerCast() into a method
...
llvm-svn: 50836
2008-05-07 22:54:15 +00:00
5a3eecdfd8
Fix a bug in the ComputeMaskedBits logic for multiply.
...
llvm-svn: 50793
2008-05-07 00:35:55 +00:00
82c02b28f3
Make StripPointerCast a common function (should we mak it method of Value instead?)
...
llvm-svn: 50775
2008-05-06 22:52:30 +00:00
7ffc3c9a95
Fix typo.
...
llvm-svn: 50713
2008-05-06 05:40:11 +00:00
cf0e3acf16
Correct the value of LowBits in srem and urem handling in
...
ComputeMaskedBits.
llvm-svn: 50692
2008-05-06 00:51:48 +00:00
a1ec89fbf1
Do not sink getresult.
...
llvm-svn: 50600
2008-05-03 00:36:30 +00:00
1962c2be6a
Fix a mistake in the computation of leading zeros for udiv.
...
llvm-svn: 50591
2008-05-02 21:30:02 +00:00
4be6ae4e6c
Fix an overaggressive SimplifyDemandedBits optimization on urem. This
...
fixes the 254.gap regression on x86 and the 403.gcc regression on x86-64.
llvm-svn: 50537
2008-05-01 19:13:24 +00:00
2dc4426675
move lowering of llvm.memset -> store from simplify libcalls
...
to instcombine.
llvm-svn: 50472
2008-04-30 06:39:11 +00:00
d9e3b5c5bd
don't eliminate load from volatile value on paths where the load is dead.
...
This fixes the second half of PR2262
llvm-svn: 50430
2008-04-29 17:28:22 +00:00
9233c124c9
fix a subtle volatile handling bug.
...
llvm-svn: 50428
2008-04-29 17:13:43 +00:00
e331a65c79
don't delete the last store to an alloca if the store is volatile.
...
llvm-svn: 50390
2008-04-29 04:58:38 +00:00
72ec3f4562
Teach InstCombine's ComputeMaskedBits what SelectionDAG's
...
ComputeMaskedBits knows about cttz, ctlz, and ctpop. Teach
SelectionDAG's ComputeMaskedBits what InstCombine's knows
about SRem. And teach them both some things about high bits
in Mul, UDiv, URem, and Sub. This allows instcombine and
dagcombine to eliminate sign-extension operations in
several new cases.
llvm-svn: 50358
2008-04-28 17:02:21 +00:00
0d1d3df564
change comments per review
...
llvm-svn: 50300
2008-04-25 21:16:07 +00:00
4d43d3c72c
Remove 'unwinds to' support from mainline. This patch undoes r47802 r47989
...
r48047 r48084 r48085 r48086 r48088 r48096 r48099 r48109 and r48123.
llvm-svn: 50265
2008-04-25 16:53:59 +00:00
f6e15a4774
Rewrite previous patch to suit Chris's preference.
...
llvm-svn: 50174
2008-04-23 18:34:37 +00:00
493527d8c9
Do not change the type of a ByVal argument to a
...
type of a different size.
llvm-svn: 50121
2008-04-23 01:03:05 +00:00
1c89ca7295
Don't do: "(X & 4) >> 1 == 2 --> (X & 4) == 4" if there are more than one uses of the shift result.
...
llvm-svn: 50118
2008-04-23 00:38:06 +00:00
8fb13cbe4e
remove dead code.
...
llvm-svn: 50080
2008-04-22 03:21:48 +00:00
c3a439351c
optimize "p != gep p, ..." better. This allows us to compile
...
getelementptr-seteq.ll into:
define i1 @test(i64 %X, %S* %P) {
%C = icmp eq i64 %X, -1 ; <i1> [#uses=1]
ret i1 %C
}
instead of:
define i1 @test(i64 %X, %S* %P) {
%A.idx.mask = and i64 %X, 4611686018427387903 ; <i64> [#uses=1]
%C = icmp eq i64 %A.idx.mask, 4611686018427387903 ; <i1> [#uses=1]
ret i1 %C
}
And fixes the second half of PR2235. This speeds up the insertion sort
case by 45%, from 1.12s to 0.77s. In practice, this will significantly
speed up for loops structured like:
for (double *P = Base + N; P != Base; --P)
...
Which happens frequently for C++ iterators.
llvm-svn: 50079
2008-04-22 02:53:33 +00:00
ab20784740
g++-4.3 build-fix: CHAR_BIT requires <climits>.
...
llvm-svn: 49989
2008-04-20 08:33:11 +00:00
3b18762f40
Switch to using Simplified ConstantFP::get API.
...
llvm-svn: 49977
2008-04-20 00:41:09 +00:00
99b7b3f03b
Teach InstCombine's ComputeMaskedBits to handle pointer expressions
...
in addition to integer expressions. Rewrite GetOrEnforceKnownAlignment
as a ComputeMaskedBits problem, moving all of its special alignment
knowledge to ComputeMaskedBits as low-zero-bits knowledge.
Also, teach ComputeMaskedBits a few basic things about Mul and PHI
instructions.
This improves ComputeMaskedBits-based simplifications in a few cases,
but more noticeably it significantly improves instcombine's alignment
detection for loads, stores, and memory intrinsics.
llvm-svn: 49492
2008-04-10 18:43:06 +00:00
e9ecc68d8f
API changes for class Use size reduction, wave 1.
...
Specifically, introduction of XXX::Create methods
for Users that have a potentially variable number of
Uses.
llvm-svn: 49277
2008-04-06 20:25:17 +00:00
f2b0b0eb17
Don't eliminate bitcast instructions that change the type of a pointer
...
llvm-svn: 48971
2008-03-31 00:22:16 +00:00
2b72c05992
Handle a special case xor undef, undef -> 0. Technically this should be transformed to undef. But this is such a common idiom (misuse) we are going to handle it.
...
llvm-svn: 48791
2008-03-25 20:07:13 +00:00
c3cf9f872a
Transform (zext (or (icmp), (icmp))) to (or (zext (cimp), (zext icmp))) if at least one of the (zext icmp) can be transformed to eliminate an icmp.
...
llvm-svn: 48715
2008-03-24 00:21:34 +00:00
c9e09a0588
Fix the build for gcc-4.2.
...
llvm-svn: 48639
2008-03-21 08:32:17 +00:00
c44160ce6e
Teach masked value is zero about add and sub, and use MVIZ to
...
simplify things like (X & 4) >> 1 == 2 --> (X & 4) == 4.
since it is obvious that the shift doesn't remove any bits.
llvm-svn: 48631
2008-03-21 05:19:58 +00:00
68a930b33e
The inst combining of inttoptr into GEP with one index was using the bit size of
...
the type instead of the byte size. This was causing troublesome mis-compilations.
True to form, this took 2 days to find and is a one-line fix. :-P
llvm-svn: 48354
2008-03-14 05:12:19 +00:00
8a923e7c28
Reimplement the parameter attributes support, phase #1 . hilights:
...
1. There is now a "PAListPtr" class, which is a smart pointer around
the underlying uniqued parameter attribute list object, and manages
its refcount. It is now impossible to mess up the refcount.
2. PAListPtr is now the main interface to the underlying object, and
the underlying object is now completely opaque.
3. Implementation details like SmallVector and FoldingSet are now no
longer part of the interface.
4. You can create a PAListPtr with an arbitrary sequence of
ParamAttrsWithIndex's, no need to make a SmallVector of a specific
size (you can just use an array or scalar or vector if you wish).
5. All the client code that had to check for a null pointer before
dereferencing the pointer is simplified to just access the
PAListPtr directly.
6. The interfaces for adding attrs to a list and removing them is a
bit simpler.
Phase #2 will rename some stuff (e.g. PAListPtr) and do other less
invasive changes.
llvm-svn: 48289
2008-03-12 17:45:29 +00:00
70c238a1d8
Skip functions that return multiple values.
...
llvm-svn: 48233
2008-03-11 18:04:06 +00:00
271506f29c
Don't eliminate blocks that are only reachable by unwind_to.
...
llvm-svn: 48106
2008-03-09 08:50:23 +00:00
d0b62a1552
Don't try to simplify urem and srem using arithmetic rules that don't work
...
under modulo (overflow). Fixes PR1933.
llvm-svn: 47987
2008-03-06 06:48:30 +00:00
c612571555
Folding or(fcmp,fcmp) only works if the operands of the fcmps are the same fp type.
...
llvm-svn: 47750
2008-02-29 06:09:11 +00:00
d188e03715
De-tabify.
...
llvm-svn: 47599
2008-02-26 10:53:30 +00:00
09f410b6d7
Split ParameterAttributes.h, putting the complicated
...
stuff into ParamAttrsList.h. Per feedback from
ParamAttrs changes.
llvm-svn: 47504
2008-02-22 22:17:59 +00:00
3b8eb704fc
Fixed a typo.
...
llvm-svn: 47478
2008-02-22 10:00:35 +00:00
18991d78fa
Fix newly-introduced 4.3 warnings
...
llvm-svn: 47375
2008-02-20 12:07:57 +00:00
1bfd121321
Make Transforms to be 4.3 warnings-clean
...
llvm-svn: 47371
2008-02-20 11:26:25 +00:00
89268bc6e2
Expand ParameterAttributes to 32 bits (in preparation
...
for adding alignment info, not there yet). Clean up
interfaces to reference ParameterAttributes consistently.
llvm-svn: 47342
2008-02-19 21:38:47 +00:00
0fe6bce9ce
fdiv/frem of undef can produce undef, because the undef operand
...
can be a SNaN. We could be more aggressive and turn this into
unreachable, but that is less nice, and not really worth it.
llvm-svn: 47313
2008-02-19 06:12:18 +00:00
fefd0202c9
Correctly fold divide-by-constant, even when faced with overflow.
...
llvm-svn: 47287
2008-02-18 22:48:05 +00:00
1e3c501cb8
Transforming -A + -B --> -(A + B) isn't safe for FP, thanks
...
to Dale for noticing this!
llvm-svn: 47276
2008-02-18 17:50:16 +00:00
024f8c8f09
optimize away stackrestore calls that have no intervening alloca or call.
...
llvm-svn: 47258
2008-02-18 06:12:38 +00:00
Chris Lattner