Users of ValueLatticeElement currently have to ensure constant ranges
are not extended indefinitely. For example, in SCCP, mergeIn goes to
overdefined if a constantrange value is repeatedly merged with larger
constantranges. This is a simple form of widening.
In some cases, this leads to an unnecessary loss of information and
things can be improved by allowing a small number of extensions in the
hope that a fixed point is reached after a small number of steps.
To make better decisions about widening, it is helpful to keep track of
the number of range extensions. That state is tied directly to a
concrete ValueLatticeElement and some unused bits in the class can be
used. The current patch preserves the existing behavior by default:
CheckWiden defaults to false and if CheckWiden is true, a single change
to the range is allowed.
Follow-up patches will slightly increase the threshold for widening.
Reviewers: efriedma, davide, mssimpso
Reviewed By: efriedma
Differential Revision: https://reviews.llvm.org/D78145
For non-integer constants/expressions and overdefined, I think we can
just use SimplifyBinOp to do common folds. By just passing a context
with the DL, SimplifyBinOp should not try to get additional information
from looking at definitions.
For overdefined values, it should be enough to just pass the original
operand.
Note: The comment before the `if (isconstant(V1State)...` was wrong
originally: isConstant() also matches integer ranges with a single
element. It is correct now.
Reviewers: efriedma, davide, mssimpso, aartbik
Reviewed By: efriedma
Differential Revision: https://reviews.llvm.org/D76459
This patch updates the code that deals with conditions from predicate
info to make use of constant ranges.
For ssa_copy instructions inserted by PredicateInfo, we have 2 ranges:
1. The range of the original value.
2. The range imposed by the linked condition.
1. is known, 2. can be determined using makeAllowedICmpRegion. The
intersection of those ranges is the range for the copy.
With this patch, we get a nice increase in the number of instructions
eliminated by both SCCP and IPSCCP for some benchmarks:
For MultiSource, SPEC2000 & SPEC2006:
Tests: 237
Same hash: 170 (filtered out)
Remaining: 67
Metric: sccp.NumInstRemoved
Program base patch diff
test-suite...Source/Benchmarks/sim/sim.test 10.00 71.00 610.0%
test-suite...CFP2000/177.mesa/177.mesa.test 361.00 1626.00 350.4%
test-suite...encode/alacconvert-encode.test 141.00 602.00 327.0%
test-suite...decode/alacconvert-decode.test 141.00 602.00 327.0%
test-suite...CI_Purple/SMG2000/smg2000.test 1639.00 4093.00 149.7%
test-suite...peg2/mpeg2dec/mpeg2decode.test 75.00 163.00 117.3%
test-suite...T2006/401.bzip2/401.bzip2.test 358.00 513.00 43.3%
test-suite...rks/FreeBench/pifft/pifft.test 11.00 15.00 36.4%
test-suite...langs-C/unix-tbl/unix-tbl.test 4.00 5.00 25.0%
test-suite...lications/sqlite3/sqlite3.test 541.00 667.00 23.3%
test-suite.../CINT2000/254.gap/254.gap.test 243.00 299.00 23.0%
test-suite...ks/Prolangs-C/agrep/agrep.test 25.00 29.00 16.0%
test-suite...marks/7zip/7zip-benchmark.test 1135.00 1304.00 14.9%
test-suite...lications/ClamAV/clamscan.test 1105.00 1268.00 14.8%
test-suite...urce/Applications/lua/lua.test 398.00 436.00 9.5%
Metric: sccp.IPNumInstRemoved
Program base patch diff
test-suite...C/CFP2000/179.art/179.art.test 1.00 3.00 200.0%
test-suite...006/447.dealII/447.dealII.test 429.00 1056.00 146.2%
test-suite...nch/fourinarow/fourinarow.test 3.00 7.00 133.3%
test-suite...CI_Purple/SMG2000/smg2000.test 818.00 1748.00 113.7%
test-suite...ks/McCat/04-bisect/bisect.test 3.00 5.00 66.7%
test-suite...CFP2000/177.mesa/177.mesa.test 165.00 255.00 54.5%
test-suite...ediabench/gsm/toast/toast.test 18.00 27.00 50.0%
test-suite...telecomm-gsm/telecomm-gsm.test 18.00 27.00 50.0%
test-suite...ks/Prolangs-C/agrep/agrep.test 24.00 35.00 45.8%
test-suite...TimberWolfMC/timberwolfmc.test 43.00 62.00 44.2%
test-suite...encode/alacconvert-encode.test 46.00 66.00 43.5%
test-suite...decode/alacconvert-decode.test 46.00 66.00 43.5%
test-suite...langs-C/unix-tbl/unix-tbl.test 12.00 17.00 41.7%
test-suite...peg2/mpeg2dec/mpeg2decode.test 31.00 41.00 32.3%
test-suite.../CINT2000/254.gap/254.gap.test 117.00 154.00 31.6%
Reviewers: efriedma, davide
Reviewed By: efriedma
Differential Revision: https://reviews.llvm.org/D76611
For casts with constant range operands, we can use
ConstantRange::castOp.
Reviewers: davide, efriedma, mssimpso
Reviewed By: efriedma
Differential Revision: https://reviews.llvm.org/D71938
The LatticeVal alias was introduced to reduce the diff size for the
transition to ValueLatticeElement, which is done now.
This patch removes the unnecessary alias and updates some very verbose
type uses with auto.
For PHIs with multiple incoming values, we can improve precision by
using constant ranges for integers. We can over-approximate phis
by merging the incoming values.
Reviewers: davide, efriedma, mssimpso
Reviewed By: efriedma
Differential Revision: https://reviews.llvm.org/D71933
If one of the operands of a binary operator is a constant range, we can
use ConstantRange::binaryOp to approximate the result.
We still handle single element constant ranges as we did previously,
with ConstantExpr::get(), because ConstantRange::binaryOp still gives
worse results in a few cases for single element ranges.
Also note that we bail out early if any of the operands is still unknown.
Reviewers: davide, efriedma, mssimpso
Reviewed By: efriedma
Differential Revision: https://reviews.llvm.org/D71936
For selects with an unknown condition, we can approximate the result by
merging the state of both options. This automatically takes care of
the case where on operand is undef.
Reviewers: davide, efriedma, mssimpso
Reviewed By: efriedma
Differential Revision: https://reviews.llvm.org/D71935
Functions include their arguments in the use-list. Changed function
values mean that the result of the function changed. We only need
to update the call sites with the new function result and do not
have to propagate the call arguments.
To do so, this patch splits up the visitCallSite into handleCallResult
and handleCallArguments and updates markUsersAsChanged to only update
call results for functions.
Reviewers: efriedma, davide
Reviewed By: efriedma
Differential Revision: https://reviews.llvm.org/D75846
This patch adds a new undef lattice state, which is used to represent
UndefValue constants or instructions producing undef.
The main difference to the unknown state is that merging undef values
with constants (or single element constant ranges) produces the
constant/constant range, assuming all uses of the merge result will be
replaced by the found constant.
Contrary, merging non-single element ranges with undef needs to go to
overdefined. Using unknown for UndefValues currently causes mis-compiles
in CVP/LVI (PR44949) and will become problematic once we use
ValueLatticeElement for SCCP.
Reviewers: efriedma, reames, davide, nikic
Reviewed By: efriedma
Differential Revision: https://reviews.llvm.org/D75120
This patch switches SCCP to use ValueLatticeElement for lattice values,
instead of the local LatticeVal, as first step to enable integer range support.
This patch does not make use of constant ranges for additional operations
and the only difference for now is that integer constants are represented by
single element ranges. To preserve the existing behavior, the following helpers
are used
* isConstant(LV): returns true when LV is either a constant or a constant range with a single element. This should return true in the same cases where LV.isConstant() returned true previously.
* getConstant(LV): returns a constant if LV is either a constant or a constant range with a single element. This should return a constant in the same cases as LV.getConstant() previously.
* getConstantInt(LV): same as getConstant, but additionally casted to ConstantInt.
Reviewers: davide, efriedma, mssimpso
Reviewed By: efriedma
Differential Revision: https://reviews.llvm.org/D60582
For tracked globals that are unknown after solving, we expect all
non-store uses to be replaced.
This is a follow-up to f8045b250d, which removed forcedconstant.
We should not mark unknown loads as overdefined, as they either load
from an unknown pointer or an undef global. Restore the original logic
for loads.
This includes a fix for cases where things get marked as overdefined in
ResolvedUndefsIn, but we later discover a constant. To avoid crashing,
we consistently bail out on overdefined values in the visitors. This is
similar to the previous behavior with forcedconstant.
This reverts the revert commit 02b72f564c.
This version includes a fix for a set of crashes caused by marking
values depending on a yet unknown & tracked call as overdefined.
In some cases, we would later discover that the call has a constant
result and try to mark a user of it as constant, although it was already
marked as overdefined. Most instruction handlers bail out early if the
instruction is already overdefined. But that is not necessary for
CastInsts for example. By skipping values that depend on skipped
calls, we resolve the crashes and also improve the precision in some
cases (see resolvedundefsin-tracked-fn.ll).
Note that we may not skip PHI nodes that may depend on a skipped call,
but they can be safely marked as overdefined, as we bail out early if
the PHI node is overdefined.
This reverts the revert commit
a74b31a3e9cd844c7ce2087978568e3f5ec8519.
This causes a crash for the reproducer below
enum { a };
enum b { c, d };
e;
static _Bool g(struct f *h, enum b i) {
i &&j();
return a;
}
static k(char h, enum b i) {
_Bool l = g(e, i);
l;
}
m(h) {
k(h, c);
g(h, d);
}
This reverts commit aadb635e04.
This patch removes forcedconstant to simplify things for the
move to ValueLattice, which includes constant ranges, but no
forced constants.
This patch removes forcedconstant and changes ResolvedUndefsIn
to mark instructions with unknown operands as overdefined. This
means we do not do simplifications based on undef directly in SCCP
any longer, but this seems to hardly come up in practice (see stats
below), presumably because InstCombine & others take care
of most of the relevant folds already.
It is still beneficial to keep ResolvedUndefIn, as it allows us delaying
going to overdefined until we propagated all known information.
I also built MultiSource, SPEC2000 and SPEC2006 and compared
sccp.IPNumInstRemoved and sccp.NumInstRemoved. It looks like the impact
is quite low:
Tests: 244
Same hash: 238 (filtered out)
Remaining: 6
Metric: sccp.IPNumInstRemoved
Program base patch diff
test-suite...arks/VersaBench/dbms/dbms.test 4.00 3.00 -25.0%
test-suite...TimberWolfMC/timberwolfmc.test 38.00 34.00 -10.5%
test-suite...006/453.povray/453.povray.test 158.00 155.00 -1.9%
test-suite.../CINT2000/176.gcc/176.gcc.test 668.00 668.00 0.0%
test-suite.../CINT2006/403.gcc/403.gcc.test 1209.00 1209.00 0.0%
test-suite...arks/mafft/pairlocalalign.test 76.00 76.00 0.0%
Tests: 244
Same hash: 238 (filtered out)
Remaining: 6
Metric: sccp.NumInstRemoved
Program base patch diff
test-suite...arks/mafft/pairlocalalign.test 185.00 175.00 -5.4%
test-suite.../CINT2006/403.gcc/403.gcc.test 2059.00 2056.00 -0.1%
test-suite.../CINT2000/176.gcc/176.gcc.test 2358.00 2357.00 -0.0%
test-suite...006/453.povray/453.povray.test 317.00 317.00 0.0%
test-suite...TimberWolfMC/timberwolfmc.test 12.00 12.00 0.0%
Reviewers: davide, efriedma, mssimpso
Reviewed By: efriedma
Differential Revision: https://reviews.llvm.org/D61314
We currently use integer ranges to merge concrete function arguments.
We use the ParamState range for those, but we only look up concrete
values in the regular state. For concrete function arguments that are
themselves arguments of the containing function, we can use the param
state directly and improve the precision in some cases.
Besides improving the results in some cases, this is also a small step towards
switching to ValueLatticeElement, by allowing D60582 to be a NFC.
Reviewers: efriedma, davide
Reviewed By: efriedma
Differential Revision: https://reviews.llvm.org/D71836
This file lists every pass in LLVM, and is included by Pass.h, which is
very popular. Every time we add, remove, or rename a pass in LLVM, it
caused lots of recompilation.
I found this fact by looking at this table, which is sorted by the
number of times a file was changed over the last 100,000 git commits
multiplied by the number of object files that depend on it in the
current checkout:
recompiles touches affected_files header
342380 95 3604 llvm/include/llvm/ADT/STLExtras.h
314730 234 1345 llvm/include/llvm/InitializePasses.h
307036 118 2602 llvm/include/llvm/ADT/APInt.h
213049 59 3611 llvm/include/llvm/Support/MathExtras.h
170422 47 3626 llvm/include/llvm/Support/Compiler.h
162225 45 3605 llvm/include/llvm/ADT/Optional.h
158319 63 2513 llvm/include/llvm/ADT/Triple.h
140322 39 3598 llvm/include/llvm/ADT/StringRef.h
137647 59 2333 llvm/include/llvm/Support/Error.h
131619 73 1803 llvm/include/llvm/Support/FileSystem.h
Before this change, touching InitializePasses.h would cause 1345 files
to recompile. After this change, touching it only causes 550 compiles in
an incremental rebuild.
Reviewers: bkramer, asbirlea, bollu, jdoerfert
Differential Revision: https://reviews.llvm.org/D70211
The static analyzer is warning about a potential null dereference, but we should be able to use cast<StructType> directly and if not assert will fire for us.
llvm-svn: 373095
Summary:
This is the first change to enable the TLI to be built per-function so
that -fno-builtin* handling can be migrated to use function attributes.
See discussion on D61634 for background. This is an enabler for fixing
handling of these options for LTO, for example.
This change should not affect behavior, as the provided function is not
yet used to build a specifically per-function TLI, but rather enables
that migration.
Most of the changes were very mechanical, e.g. passing a Function to the
legacy analysis pass's getTLI interface, or in Module level cases,
adding a callback. This is similar to the way the per-function TTI
analysis works.
There was one place where we were looking for builtins but not in the
context of a specific function. See FindCXAAtExit in
lib/Transforms/IPO/GlobalOpt.cpp. I'm somewhat concerned my workaround
could provide the wrong behavior in some corner cases. Suggestions
welcome.
Reviewers: chandlerc, hfinkel
Subscribers: arsenm, dschuff, jvesely, nhaehnle, mehdi_amini, javed.absar, sbc100, jgravelle-google, eraman, aheejin, steven_wu, george.burgess.iv, dexonsmith, jfb, asbirlea, gchatelet, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D66428
llvm-svn: 371284
We have some code marks instructions with struct operands as overdefined,
but if the instruction is a call to a function with tracked arguments,
this breaks the assumption that the lattice values of all call sites
are not overdefined and will be replaced by a constant.
This also re-adds the assertion from D65222, with additionally skipping
non-callsite uses. This patch should address the cases reported in which
the assertion fired.
Fixes PR42738.
Reviewers: efriedma, davide
Reviewed By: efriedma
Differential Revision: https://reviews.llvm.org/D65439
llvm-svn: 367430
We should only zap returns in functions, where all live users have a
replace-able value (are not overdefined). Unused return values should be
undefined.
This should make it easier to detect bugs like in PR42738.
Alternatively we could bail out of zapping the function returns, but I
think it would be better to address those divergences between function
and call-site values where they are actually caused.
Reviewers: davide, efriedma
Reviewed By: davide, efriedma
Differential Revision: https://reviews.llvm.org/D65222
llvm-svn: 366998
If we fold a branch/switch to an unconditional branch to another dead block we
replace the branch with unreachable, to avoid attempting to fold the
unconditional branch.
Reviewers: davide, efriedma, mssimpso, jdoerfert
Reviewed By: jdoerfert
Differential Revision: https://reviews.llvm.org/D61300
llvm-svn: 360232
This patch accompanies the RFC posted here:
http://lists.llvm.org/pipermail/llvm-dev/2018-October/127239.html
This patch adds a new CallBr IR instruction to support asm-goto
inline assembly like gcc as used by the linux kernel. This
instruction is both a call instruction and a terminator
instruction with multiple successors. Only inline assembly
usage is supported today.
This also adds a new INLINEASM_BR opcode to SelectionDAG and
MachineIR to represent an INLINEASM block that is also
considered a terminator instruction.
There will likely be more bug fixes and optimizations to follow
this, but we felt it had reached a point where we would like to
switch to an incremental development model.
Patch by Craig Topper, Alexander Ivchenko, Mikhail Dvoretckii
Differential Revision: https://reviews.llvm.org/D53765
llvm-svn: 353563
to reflect the new license.
We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.
Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.
llvm-svn: 351636
OriginalOp of a Predicate refers to the original IR value,
before renaming. While solving in IPSCCP, we have to use
the operand of the ssa_copy instead, to avoid missing
updates for nested conditions on the same IR value.
Fixes PR39772.
llvm-svn: 347524
After D45330, Dominators are required for IPSCCP and can be preserved.
This patch preserves DominatorTreeAnalysis in the new pass manager. AFAIK the legacy pass manager cannot preserve function analysis required by a module analysis.
Reviewers: davide, dberlin, chandlerc, efriedma, kuhar, NutshellySima
Reviewed By: chandlerc, kuhar, NutshellySima
Differential Revision: https://reviews.llvm.org/D47259
llvm-svn: 346486
This adds the llvm-side support for post-inlining evaluation of the
__builtin_constant_p GCC intrinsic.
Also fixed SCCPSolver::visitCallSite to not blow up when seeing a call
to a function where canConstantFoldTo returns true, and one of the
arguments is a struct.
Updated from patch initially by Janusz Sobczak.
Differential Revision: https://reviews.llvm.org/D4276
llvm-svn: 346322
are terminators without relying on the specific `TerminatorInst` type.
This required cleaning up two users of `InstVisitor`s usage of
`TerminatorInst` as well.
llvm-svn: 344503
by `getTerminator()` calls instead be declared as `Instruction`.
This is the biggest remaining chunk of the usage of `getTerminator()`
that insists on the narrow type and so is an easy batch of updates.
Several files saw more extensive updates where this would cascade to
requiring API updates within the file to use `Instruction` instead of
`TerminatorInst`. All of these were trivial in nature (pervasively using
`Instruction` instead just worked).
llvm-svn: 344502
Summary:
Before removing basic blocks that ipsccp has considered as dead
all uses of the basic block label must be removed. That is done
by calling ConstantFoldTerminator on the users. An exception
is when the branch condition is an undef value. In such
scenarios ipsccp is using some internal assumptions regarding
which edge in the control flow that should remain, while
ConstantFoldTerminator don't know how to fold the terminator.
The problem addressed here is related to ConstantFoldTerminator's
ability to rewrite a 'switch' into a conditional 'br'. In such
situations ConstantFoldTerminator returns true indicating that
the terminator has been rewritten. However, ipsccp treated the
true value as if the edge to the dead basic block had been
removed. So the code for resolving an undef branch condition
did not trigger, and we ended up with assertion that there were
uses remaining when deleting the basic block.
The solution is to resolve indeterminate branches before the
call to ConstantFoldTerminator.
Reviewers: efriedma, fhahn, davide
Reviewed By: fhahn
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D52232
llvm-svn: 342632
This is a bit awkward in a handful of places where we didn't even have
an instruction and now we have to see if we can build one. But on the
whole, this seems like a win and at worst a reasonable cost for removing
`TerminatorInst`.
All of this is part of the removal of `TerminatorInst` from the
`Instruction` type hierarchy.
llvm-svn: 340701
`isExceptionalTermiantor` and implement it for opcodes as well following
the common pattern in `Instruction`.
Part of removing `TerminatorInst` from the `Instruction` type hierarchy
to make it easier to share logic and interfaces between instructions
that are both terminators and not terminators.
llvm-svn: 340699
This version of the patch fixes cleaning up ssa_copy intrinsics, so it does not
crash for instructions in blocks that have been marked unreachable.
This patch updates IPSCCP to use PredicateInfo to propagate
facts to true branches predicated by EQ and to false branches
predicated by NE.
As a follow up, we should be able to extend it to also propagate additional
facts about nonnull.
Reviewers: davide, mssimpso, dberlin, efriedma
Reviewed By: davide, dberlin
Differential Revision: https://reviews.llvm.org/D45330
llvm-svn: 340525
r337828 resolves a PredicateInfo issue with unnamed types.
Original message:
This patch updates IPSCCP to use PredicateInfo to propagate
facts to true branches predicated by EQ and to false branches
predicated by NE.
As a follow up, we should be able to extend it to also propagate additional
facts about nonnull.
Reviewers: davide, mssimpso, dberlin, efriedma
Reviewed By: davide, dberlin
llvm-svn: 337904
This version contains a fix to add values for which the state in ParamState change
to the worklist if the state in ValueState did not change. To avoid adding the
same value multiple times, mergeInValue returns true, if it added the value to
the worklist. The value is added to the worklist depending on its state in
ValueState.
Original message:
For comparisons with parameters, we can use the ParamState lattice
elements which also provide constant range information. This improves
the code for PR33253 further and gets us closer to use
ValueLatticeElement for all values.
Also, as we are using the range information in the solver directly, we
do not need tryToReplaceWithConstantRange afterwards anymore.
Reviewers: dberlin, mssimpso, davide, efriedma
Reviewed By: mssimpso
Differential Revision: https://reviews.llvm.org/D43762
llvm-svn: 337548
It's more aggressive than we need to be, and leads to strange
workarounds in other places like call return value inference. Instead,
just directly mark an edge viable.
Tests by Florian Hahn.
Differential Revision: https://reviews.llvm.org/D49408
llvm-svn: 337507
Once we resolved an undef in a function we can run Solve, which could
lead to finding a constant return value for the function, which in turn
could turn undefs into constants in other functions that call it, before
resolving undefs there.
Computationally the amount of work we are doing stays the same, just the
order we process things is slightly different and potentially there are
a few less undefs to resolve.
We are still relying on the order of functions in the IR, which means
depending on the order, we are able to resolve the optimal undef first
or not. For example, if @test1 comes before @testf, we find the constant
return value of @testf too late and we cannot use it while solving
@test1.
This on its own does not lead to more constants removed in the
test-suite, probably because currently we have to be very lucky to visit
applicable functions in the right order.
Maybe we manage to come up with a better way of resolving undefs in more
'profitable' functions first.
Reviewers: efriedma, mssimpso, davide
Reviewed By: efriedma, davide
Differential Revision: https://reviews.llvm.org/D49385
llvm-svn: 337283
Summary:
Support for this option is needed for building Linux kernel.
This is a very frequently requested feature by kernel developers.
More details : https://lkml.org/lkml/2018/4/4/601
GCC option description for -fdelete-null-pointer-checks:
This Assume that programs cannot safely dereference null pointers,
and that no code or data element resides at address zero.
-fno-delete-null-pointer-checks is the inverse of this implying that
null pointer dereferencing is not undefined.
This feature is implemented in LLVM IR in this CL as the function attribute
"null-pointer-is-valid"="true" in IR (Under review at D47894).
The CL updates several passes that assumed null pointer dereferencing is
undefined to not optimize when the "null-pointer-is-valid"="true"
attribute is present.
Reviewers: t.p.northover, efriedma, jyknight, chandlerc, rnk, srhines, void, george.burgess.iv
Reviewed By: efriedma, george.burgess.iv
Subscribers: eraman, haicheng, george.burgess.iv, drinkcat, theraven, reames, sanjoy, xbolva00, llvm-commits
Differential Revision: https://reviews.llvm.org/D47895
llvm-svn: 336613
This version contains a fix to add values for which the state in ParamState change
to the worklist if the state in ValueState did not change. To avoid adding the
same value multiple times, mergeInValue returns true, if it added the value to
the worklist. The value is added to the worklist depending on its state in
ValueState.
Original message:
For comparisons with parameters, we can use the ParamState lattice
elements which also provide constant range information. This improves
the code for PR33253 further and gets us closer to use
ValueLatticeElement for all values.
Also, as we are using the range information in the solver directly, we
do not need tryToReplaceWithConstantRange afterwards anymore.
Reviewers: dberlin, mssimpso, davide, efriedma
Reviewed By: mssimpso
Differential Revision: https://reviews.llvm.org/D43762
llvm-svn: 336098
SCCP does not change the CFG, so we can mark it as preserved.
Reviewers: dberlin, efriedma, davide
Reviewed By: davide
Differential Revision: https://reviews.llvm.org/D47149
llvm-svn: 335820
changeToUnreachable may remove PHI nodes from executable blocks we found values
for and we would fail to replace them. By changing dead blocks to unreachable after
we replaced constants in all executable blocks, we ensure such PHI nodes are replaced
by their known value before.
Fixes PR37780.
Reviewers: efriedma, davide
Reviewed By: efriedma
Differential Revision: https://reviews.llvm.org/D48421
llvm-svn: 335588
This reverts commit r335206.
As discussed here: https://reviews.llvm.org/rL333740, a fix will come
tomorrow. In the meanwhile, revert this to fix some bots.
llvm-svn: 335272
r335150 should resolve the issues with the clang-with-thin-lto-ubuntu
and clang-with-lto-ubuntu builders.
Original message:
This patch updates IPSCCP to use PredicateInfo to propagate
facts to true branches predicated by EQ and to false branches
predicated by NE.
As a follow up, we should be able to extend it to also propagate additional
facts about nonnull.
Reviewers: davide, mssimpso, dberlin, efriedma
Reviewed By: davide, dberlin
llvm-svn: 335206
Review feedback from r328165. Split out just the one function from the
file that's used by Analysis. (As chandlerc pointed out, the original
change only moved the header and not the implementation anyway - which
was fine for the one function that was used (since it's a
template/inlined in the header) but not in general)
llvm-svn: 333954
This patch updates IPSCCP to use PredicateInfo to propagate
facts to true branches predicated by EQ and to false branches
predicated by NE.
As a follow up, we should be able to extend it to also propagate additional
facts about nonnull.
Reviewers: davide, mssimpso, dberlin, efriedma
Reviewed By: davide, dberlin
Differential Revision: https://reviews.llvm.org/D45330
llvm-svn: 333740
Reverting this to see if this is causing the failures of the
clang-with-thin-lto-ubuntu bot.
[IPSCCP] Use PredicateInfo to propagate facts from cmp instructions.
This patch updates IPSCCP to use PredicateInfo to propagate
facts to true branches predicated by EQ and to false branches
predicated by NE.
As a follow up, we should be able to extend it to also propagate additional
facts about nonnull.
Reviewers: davide, mssimpso, dberlin, efriedma
Reviewed By: davide, dberlin
Differential Revision: https://reviews.llvm.org/D45330
llvm-svn: 333323
This patch updates IPSCCP to use PredicateInfo to propagate
facts to true branches predicated by EQ and to false branches
predicated by NE.
As a follow up, we should be able to extend it to also propagate additional
facts about nonnull.
Reviewers: davide, mssimpso, dberlin, efriedma
Reviewed By: davide, dberlin
Differential Revision: https://reviews.llvm.org/D45330
llvm-svn: 333268
The DEBUG() macro is very generic so it might clash with other projects.
The renaming was done as follows:
- git grep -l 'DEBUG' | xargs sed -i 's/\bDEBUG\s\?(/LLVM_DEBUG(/g'
- git diff -U0 master | ../clang/tools/clang-format/clang-format-diff.py -i -p1 -style LLVM
- Manual change to APInt
- Manually chage DOCS as regex doesn't match it.
In the transition period the DEBUG() macro is still present and aliased
to the LLVM_DEBUG() one.
Differential Revision: https://reviews.llvm.org/D43624
llvm-svn: 332240
For comparisons with parameters, we can use the ParamState lattice
elements which also provide constant range information. This improves
the code for PR33253 further and gets us closer to use
ValueLatticeElement for all values.
Also, as we are using the range information in the solver directly, we
do not need tryToReplaceWithConstantRange afterwards anymore.
Reviewers: dberlin, mssimpso, davide, efriedma
Reviewed By: mssimpso
Differential Revision: https://reviews.llvm.org/D43762
llvm-svn: 328307
Transforms/Scalar/SCCP.cpp implemented both the Scalar and IPO SCCP, but
this meant Transforms/Scalar including Transfroms/IPO headers, creating
a circular dependency. (IPO depends on Scalar already) - so move the IPO
SCCP shims out into IPO and the basic library implementation accessible
from Scalar/SCCP.h to be used from the IPO/SCCP.cpp implementation.
llvm-svn: 328250
Remove #include of Transforms/Scalar.h from Transform/Utils to fix layering.
Transforms depends on Transforms/Utils, not the other way around. So
remove the header and the "createStripGCRelocatesPass" function
declaration (& definition) that is unused and motivated this dependency.
Move Transforms/Utils/Local.h into Analysis because it's used by
Analysis/MemoryBuiltins.cpp.
llvm-svn: 328165
getCompare returns true, false or undef constants if the comparison can
be evaluated, or nullptr if it cannot. This is in line with what
ConstantExpr::getCompare returns. It also allows us to use
ConstantExpr::getCompare for comparing constants.
Reviewers: davide, mssimpso, dberlin, anna
Reviewed By: davide
Differential Revision: https://reviews.llvm.org/D43761
llvm-svn: 326720
Do not replace results of `musttail` calls with a constant if the
call itself can't be removed.
Do not zap returns of `musttail` callees, if the call site can't be
removed and replaced with a constant.
Do not zap returns of `musttail`-calling blocks, this breaks
invariant too.
Patch by Fedor Indutny
Differential Revision: https://reviews.llvm.org/D43695
llvm-svn: 326404
Summary:
When performing constant propagation for call instructions we have historically replaced all uses of the return from a call, but not removed the call itself. This is required for correctness if the calls have side effects, however the compiler should be able to safely remove calls that don't have side effects.
This allows the compiler to completely fold away calls to functions that have no side effects if the inputs are constant and the output can be determined at compile time.
Reviewers: davide, sanjoy, bruno, dberlin
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D38856
llvm-svn: 322125
This code was originally removed and replace with an assertion
because believed unnecessary. It turns out there was simply
no test coverage for this case, and the constant folder doesn't
yet know about patterns like `br undef %label1, %label2`.
Presumably at some point the constant folder might learn about
these patterns, but it's a broader change.
A testcase will be added to make sure this doesn't regress again
in the future.
Fixes PR35723.
llvm-svn: 321402
After the dataflow algorithm proves that an argument is constant,
it replaces it value with the integer constant and drops the lattice
value associated to the DEF.
e.g. in the example we have @f() that's called twice:
call @f(undef, ...)
call @f(2, ...)
`undef` MEET 2 = 2 so we replace the argument and all its uses with
the constant 2.
Shortly after, tryToReplaceWithConstantRange() tries to get the lattice
value for the argument we just replaced, causing an assertion.
This function is a little peculiar as it runs when we're doing replacement
and not as part of the solver but still queries the solver.
The fix is that of checking whether we replaced the value already and
get a temporary lattice value for the constant.
Thanks to Zhendong Su for the report!
Fixes PR35357.
llvm-svn: 318817
This version of the patch includes a fix addressing a stage2 LTO buildbot
failure and addressed some additional nits.
Original commit message:
This updates the SCCP solver to use of the ValueElement lattice for
parameters, which provides integer range information. The range
information is used to remove unneeded icmp instructions.
For the following function, f() can be optimized to ret i32 2 with
this change
source_filename = "sccp.c"
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
; Function Attrs: norecurse nounwind readnone uwtable
define i32 @main() local_unnamed_addr #0 {
entry:
%call = tail call fastcc i32 @f(i32 1)
%call1 = tail call fastcc i32 @f(i32 47)
%add3 = add nsw i32 %call, %call1
ret i32 %add3
}
; Function Attrs: noinline norecurse nounwind readnone uwtable
define internal fastcc i32 @f(i32 %x) unnamed_addr #1 {
entry:
%c1 = icmp sle i32 %x, 100
%cmp = icmp sgt i32 %x, 300
%. = select i1 %cmp, i32 1, i32 2
ret i32 %.
}
attributes #1 = { noinline }
Reviewers: davide, sanjoy, efriedma, dberlin
Reviewed By: davide, dberlin
Subscribers: mcrosier, gberry, mssimpso, dberlin, llvm-commits
Differential Revision: https://reviews.llvm.org/D36656
llvm-svn: 316891
This version of the patch includes a fix addressing a stage2 LTO buildbot
failure and addressed some additional nits.
Original commit message:
This updates the SCCP solver to use of the ValueElement lattice for
parameters, which provides integer range information. The range
information is used to remove unneeded icmp instructions.
For the following function, f() can be optimized to ret i32 2 with
this change
source_filename = "sccp.c"
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
; Function Attrs: norecurse nounwind readnone uwtable
define i32 @main() local_unnamed_addr #0 {
entry:
%call = tail call fastcc i32 @f(i32 1)
%call1 = tail call fastcc i32 @f(i32 47)
%add3 = add nsw i32 %call, %call1
ret i32 %add3
}
; Function Attrs: noinline norecurse nounwind readnone uwtable
define internal fastcc i32 @f(i32 %x) unnamed_addr #1 {
entry:
%c1 = icmp sle i32 %x, 100
%cmp = icmp sgt i32 %x, 300
%. = select i1 %cmp, i32 1, i32 2
ret i32 %.
}
attributes #1 = { noinline }
Reviewers: davide, sanjoy, efriedma, dberlin
Reviewed By: davide, dberlin
Subscribers: mcrosier, gberry, mssimpso, dberlin, llvm-commits
Differential Revision: https://reviews.llvm.org/D36656
llvm-svn: 316887
This patch moves some common utility functions out of IPSCCP and makes them
available globally. The functions determine if interprocedural data-flow
analyses can propagate information through function returns, arguments, and
global variables.
Differential Revision: https://reviews.llvm.org/D37638
llvm-svn: 315719
Going through the Constant methods requires redetermining that the Constant is a ConstantInt and then calling isZero/isOne/isMinusOne.
llvm-svn: 307292
Florian Hahn