exits"
Get a better approach in https://reviews.llvm.org/D68107 to solve the problem.
Revert the initial patch and will commit the new one soon.
This reverts commit rL372990.
llvm-svn: 373044
Summary: As discussed in the loop group meeting. With the current
definition of loop guard, we should not allow multiple loop exiting
blocks. For loops that has multiple loop exiting blocks, we can simply
unable to find the loop guard.
When getUniqueExitBlock() obtains a vector size not equals to one, that
means there is either no exit blocks or there exists more than one
unique block the loop exit to.
If we don't disallow loop with multiple loop exit blocks, then with our
current implementation, there can exist exit blocks don't post dominated
by the non pre-header successor of the guard block.
Reviewer: reames, Meinersbur, kbarton, etiotto, bmahjour
Reviewed By: Meinersbur, kbarton
Subscribers: fhahn, hiraditya, llvm-commits
Tag: LLVM
Differential Revision: https://reviews.llvm.org/D66529
llvm-svn: 373011
The static analyzer is warning about a potential null dereference, but we should be able to use cast<ExtractValueInst> directly and if not assert will fire for us.
llvm-svn: 372993
for extreme large case.
We had a case that a single loop which has 4000 exits and the average number
of predecessors of each exit is > 1000, and we found compiling the case spent
a significant amount of time on checking whether a loop has dedicated exits.
This patch adds a limit for the iterations to the check. With the patch, the
time to compile our testcase reduced from 1000s to 200s (clang release build).
Differential Revision: https://reviews.llvm.org/D67359
llvm-svn: 372990
The static analyzer is warning about a potential null dereferences, but since the pointer is only used in a switch statement for Operator::getOpcode() (with an empty default) then its easiest just to wrap this in a null test as the dyn_cast might return null here.
llvm-svn: 372962
Previously we might attempt to use a BitCast to turn bits into vectors of pointers,
but that requires an inttoptr cast to be legal. Add an assertion to detect the formation of illegal bitcast attempts
early (in the tests, we often constant-fold away the result before getting to this assertion check),
while being careful to still handle the early-return conditions without adding extra complexity in the result.
Patch by Jameson Nash <jameson@juliacomputing.com>.
Differential Revision: https://reviews.llvm.org/D65057
llvm-svn: 372940
Summary:
If a block has all incoming values with the same MemoryAccess (ignoring
incoming values from unreachable blocks), then use that incoming
MemoryAccess and do not create a Phi in the first place.
Revert IDF work-around added in rL372673; it should not be required unless
the Def inserted is the first in its block.
The patch also cleans up a series of tests, added during the many
iterations on insertDef.
The patch also fixes PR43438.
The same issue that occurs in insertDef with "adding phis, hence the IDF of
Phis is needed", can also occur in fixupDefs: the `getPreviousRecursive`
call only adds Phis walking on the predecessor edges, which means there
may be the case of a Phi added walking the CFG "backwards" which
triggers the needs for an additional Phi in successor blocks.
Such Phis are added during fixupDefs only in the presence of unreachable
blocks.
Hence this highlights the need to avoid adding Phis in blocks with
unreachable predecessors in the first place.
Reviewers: george.burgess.iv
Subscribers: Prazek, sanjoy.google, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D67995
llvm-svn: 372932
Because we do not constant fold multiplications in SimplifyFMAMul,
we match 1.0 and 0.0 for both operands, as multiplying by them
is guaranteed to produce an exact result (if it is allowed to do so).
Note that it is not enough to just swap the operands to ensure a
constant is on the RHS, as we want to also cover the case with
2 constants.
Reviewers: lebedev.ri, spatel, reames, scanon
Reviewed By: lebedev.ri, reames
Differential Revision: https://reviews.llvm.org/D67553
llvm-svn: 372915
As @reames pointed out post-commit, rL371518 adds additional rounding
in some cases, when doing constant folding of the multiplication.
This breaks a guarantee llvm.fma makes and must be avoided.
This patch reapplies rL371518, but splits off the simplifications not
requiring rounding from SimplifFMulInst as SimplifyFMAFMul.
Reviewers: spatel, lebedev.ri, reames, scanon
Reviewed By: reames
Differential Revision: https://reviews.llvm.org/D67434
llvm-svn: 372899
Currently m_Br only takes references to BasicBlock*, which limits its
flexibility. For example, you have to declare a variable, even if you
ignore the result or you have to have additional checks to make sure the
matched BB matches an expected one.
This patch adds m_BasicBlock and m_SpecificBB matchers, which can be
used like the existing matchers for constants or values.
I also had a look at the existing uses and updated a few. IMO it makes
the code a bit more explicit.
Reviewers: spatel, craig.topper, RKSimon, majnemer, lebedev.ri
Reviewed By: lebedev.ri
Differential Revision: https://reviews.llvm.org/D68013
llvm-svn: 372885
The changes here are based on the corresponding diffs for allowing FMF on 'select':
D61917 <https://reviews.llvm.org/D61917>
As discussed there, we want to have fast-math-flags be a property of an FP value
because the alternative (having them on things like fcmp) leads to logical
inconsistency such as:
https://bugs.llvm.org/show_bug.cgi?id=38086
The earlier patch for select made almost no practical difference because most
unoptimized conditional code begins life as a phi (based on what I see in clang).
Similarly, I don't expect this patch to do much on its own either because
SimplifyCFG promptly drops the flags when converting to select on a minimal
example like:
https://bugs.llvm.org/show_bug.cgi?id=39535
But once we have this plumbing in place, we should be able to wire up the FMF
propagation and start solving cases like that.
The change to RecurrenceDescriptor::AddReductionVar() is required to prevent a
regression in a LoopVectorize test. We are intersecting the FMF of any
FPMathOperator there, so if a phi is not properly annotated, new math
instructions may not be either. Once we fix the propagation in SimplifyCFG, it
may be safe to remove that hack.
Differential Revision: https://reviews.llvm.org/D67564
llvm-svn: 372878
The changes here are based on the corresponding diffs for allowing FMF on 'select':
D61917
As discussed there, we want to have fast-math-flags be a property of an FP value
because the alternative (having them on things like fcmp) leads to logical
inconsistency such as:
https://bugs.llvm.org/show_bug.cgi?id=38086
The earlier patch for select made almost no practical difference because most
unoptimized conditional code begins life as a phi (based on what I see in clang).
Similarly, I don't expect this patch to do much on its own either because
SimplifyCFG promptly drops the flags when converting to select on a minimal
example like:
https://bugs.llvm.org/show_bug.cgi?id=39535
But once we have this plumbing in place, we should be able to wire up the FMF
propagation and start solving cases like that.
The change to RecurrenceDescriptor::AddReductionVar() is required to prevent a
regression in a LoopVectorize test. We are intersecting the FMF of any
FPMathOperator there, so if a phi is not properly annotated, new math
instructions may not be either. Once we fix the propagation in SimplifyCFG, it
may be safe to remove that hack.
Differential Revision: https://reviews.llvm.org/D67564
llvm-svn: 372866
Summary:
MemoryPhis may be needed following a Def insertion inthe IDF of all the
new accesses added (phis + potentially a def). Ensure this also occurs when
only the new MemoryPhis are the defining accesses.
Note: The need for computing IDF here is because of new Phis added with
edges incoming from unreachable code, Phis that had previously been
simplified. The preferred solution is to not reintroduce such Phis.
This patch is the needed fix while working on the preferred solution.
Reviewers: george.burgess.iv
Subscribers: Prazek, sanjoy.google, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D67927
llvm-svn: 372673
Static analyzer complains about const_cast uninitialized variables, we should explicitly set these to null.
Ideally that const wrapper would go away though.......
llvm-svn: 372603
Summary:
The CallAnalyzer::visitSwitchInst has an early exit when the estimated
lower bound of the switch cost will put the overall cost of the inline
above the threshold. However, this code is not correctly estimating the
lower bound for switches that can be transformed into bit tests, leading
to unnecessary lost inlines, and also differing behavior with
optimization remarks enabled.
First, the early exit is controlled by whether ComputeFullInlineCost is
enabled or not, and that in turn is disabled by default but enabled when
enabling -pass-remarks=missed. This by itself wouldn't lead to a
problem, except that as described below, the lower bound can be above
the real lower bound, so we can sometimes get different inline decisions
with inline remarks enabled, which is problematic.
The early exit was added in along with a new switch cost model in D31085.
The reason why this early exit was added is due to a concern one reviewer
raised about compile time for large switches:
https://reviews.llvm.org/D31085?id=94559#inline-276200
However, the code just below there calls
getEstimatedNumberOfCaseClusters, which in turn immediately calls
BasicTTIImpl getEstimatedNumberOfCaseClusters, which in the worst case
does a linear scan of the cases to get the high and low values. The
bit test handling in particular is guarded by whether the number of
cases fits into the max bit width. There is no suggestion that anyone
measured a compile time issue, it appears to be theoretical.
The problem is that the reviewer's comment about the lower bound
calculation is incorrect, specifically in the case of a switch that can
be lowered to a bit test. This isn't followed up on the comment
thread, but the author does add a FIXME to that effect above the early
exit added when they subsequently revised the patch.
As a result, we were incorrectly early exiting and not inlining
functions with switch statements that would be lowered to bit tests in
cases where we were nearing the threshold. Combined with the fact that
this early exit was skipped with opt remarks enabled, this caused
different inlining decisions to be made when -pass-remarks=missed is
enabled to debug the missing inline.
Remove the early exit for the above reasons.
I also copied over an existing AArch64 inlining test to X86, and
adjusted the threshold so that the bit test inline only occurs with the
fix in this patch.
Reviewers: davidxl
Subscribers: eraman, kristof.beyls, haicheng, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D67716
llvm-svn: 372440
At present, `-scalar-evolution-max-iterations` is a `cl::Optional`
option, which means it demands to be passed exactly zero or one times.
Our build system makes it pretty tricky to guarantee this. We often
accidentally pass the flag more than once (but always with the same
value) which results in an error, after which compilation fails:
```
clang (LLVM option parsing): for the -scalar-evolution-max-iterations option: may only occur zero or one times!
```
It seems reasonable to allow -scalar-evolution-max-iterations to be
passed more than once. Quoting the [[ http://llvm.org/docs/CommandLine.html#controlling-the-number-of-occurrences-required-and-allowed | documentation ]]:
> The cl::ZeroOrMore modifier ... indicates that your program will allow the option to be specified zero or more times.
> ...
> If an option is specified multiple times for an option of the cl::opt class, only the last value will be retained.
Original patch by: Enrico Bern Hardy Tanuwidjaja <etanuwid@fb.com>
Differential Revision: https://reviews.llvm.org/D67512
llvm-svn: 372346
This patch implements the demangling functionality as described in the
Vector Function ABI. This patch will be used to implement the
SearchVectorFunctionSystem (SVFS) as described in the RFC:
http://lists.llvm.org/pipermail/llvm-dev/2019-June/133484.html
A fuzzer is added to test the demangling utility.
Patch by Sumedh Arani <sumedh.arani@arm.com>
Differential revision: https://reviews.llvm.org/D66024
llvm-svn: 372343
Summary:
This is the first patch in a series of patches that will implement data dependence graph in LLVM. Many of the ideas used in this implementation are based on the following paper:
D. J. Kuck, R. H. Kuhn, D. A. Padua, B. Leasure, and M. Wolfe (1981). DEPENDENCE GRAPHS AND COMPILER OPTIMIZATIONS.
This patch contains support for a basic DDGs containing only atomic nodes (one node for each instruction). The edges are two fold: def-use edges and memory-dependence edges.
The implementation takes a list of basic-blocks and only considers dependencies among instructions in those basic blocks. Any dependencies coming into or going out of instructions that do not belong to those basic blocks are ignored.
The algorithm for building the graph involves the following steps in order:
1. For each instruction in the range of basic blocks to consider, create an atomic node in the resulting graph.
2. For each node in the graph establish def-use edges to/from other nodes in the graph.
3. For each pair of nodes containing memory instruction(s) create memory edges between them. This part of the algorithm goes through the instructions in lexicographical order and creates edges in reverse order if the sink of the dependence occurs before the source of it.
Authored By: bmahjour
Reviewer: Meinersbur, fhahn, myhsu, xtian, dmgreen, kbarton, jdoerfert
Reviewed By: Meinersbur, fhahn, myhsu
Subscribers: ychen, arphaman, simoll, a.elovikov, mgorny, hiraditya, jfb, wuzish, llvm-commits, jsji, Whitney, etiotto
Tag: #llvm
Differential Revision: https://reviews.llvm.org/D65350
llvm-svn: 372238
Summary:
This fixes B42473 and B42706.
This patch makes the SDA propagate branch divergence until the end of the RPO traversal. Before, the SyncDependenceAnalysis propagated divergence only until the IPD in rpo order. RPO is incompatible with post dominance in the presence of loops. This made the SDA crash because blocks were missed in the propagation.
Reviewers: foad, nhaehnle
Reviewed By: foad
Subscribers: jvesely, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D65274
llvm-svn: 372223
Summary:
This is the first patch in a series of patches that will implement data dependence graph in LLVM. Many of the ideas used in this implementation are based on the following paper:
D. J. Kuck, R. H. Kuhn, D. A. Padua, B. Leasure, and M. Wolfe (1981). DEPENDENCE GRAPHS AND COMPILER OPTIMIZATIONS.
This patch contains support for a basic DDGs containing only atomic nodes (one node for each instruction). The edges are two fold: def-use edges and memory-dependence edges.
The implementation takes a list of basic-blocks and only considers dependencies among instructions in those basic blocks. Any dependencies coming into or going out of instructions that do not belong to those basic blocks are ignored.
The algorithm for building the graph involves the following steps in order:
1. For each instruction in the range of basic blocks to consider, create an atomic node in the resulting graph.
2. For each node in the graph establish def-use edges to/from other nodes in the graph.
3. For each pair of nodes containing memory instruction(s) create memory edges between them. This part of the algorithm goes through the instructions in lexicographical order and creates edges in reverse order if the sink of the dependence occurs before the source of it.
Authored By: bmahjour
Reviewer: Meinersbur, fhahn, myhsu, xtian, dmgreen, kbarton, jdoerfert
Reviewed By: Meinersbur, fhahn, myhsu
Subscribers: ychen, arphaman, simoll, a.elovikov, mgorny, hiraditya, jfb, wuzish, llvm-commits, jsji, Whitney, etiotto
Tag: #llvm
Differential Revision: https://reviews.llvm.org/D65350
llvm-svn: 372162
Summary:
When inserting a Def, the current algorithm is walking edges backward
and inserting new Phis where needed. There may be additional Phis needed
in the IDF of the newly inserted Def and Phis.
Adding Phis in the IDF of the Def was added ina previous patch, but we
may also need other Phis in the IDF of the newly added Phis.
Reviewers: george.burgess.iv
Subscribers: Prazek, sanjoy.google, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D67637
llvm-svn: 372138
Summary:
Regularly when moving an instruction that may not read or write memory,
the instruction is not modelled in MSSA, so not action is necessary.
For a non-conventional AA pipeline, MSSA needs to explicitly check when
creating accesses, so as to not model instructions that may not read and
write memory.
Reviewers: george.burgess.iv
Subscribers: Prazek, sanjoy.google, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D67562
llvm-svn: 372137
We were failing to compute trip counts (both exact and maximum) for any loop which involved a comparison against either an umin or smin. It looks like this simply got missed when we added smin/umin to SCEV. (Note: umin was submitted separately earlier today. Turned out two folks hit this at the same time.)
Differential Revision: https://reviews.llvm.org/D67514
llvm-svn: 371776
Expanding the folding of `nearbyint()`, `rint()` and `trunc()` to library
functions, in addition to the current support for intrinsics.
Differential revision: https://reviews.llvm.org/D67468
llvm-svn: 371774
This patch adds support for SCEVUMinExpr to getRangeRef,
similar to the support for SCEVUMaxExpr.
Reviewers: sanjoy.google, efriedma, reames, nikic
Reviewed By: sanjoy.google
Differential Revision: https://reviews.llvm.org/D67177
llvm-svn: 371768
Implement a TODO from rL371452, and handle loop invariant addresses in predicated blocks. If we can prove that the load is safe to speculate into the header, then we can avoid using a masked.load in favour of a normal load.
This is mostly about vectorization robustness. In the common case, it's generally expected that LICM/LoadStorePromotion would have eliminated such loads entirely.
Differential Revision: https://reviews.llvm.org/D67372
llvm-svn: 371745
Folding for fma/fmuladd was added here:
rL202914
...and as seen in existing/unchanged tests, that works to propagate NaN
if it's already an input, but we should fold an fma() that creates NaN too.
From IEEE-754-2008 7.2 "Invalid Operation", there are 2 clauses that apply
to fma, so I added tests for those patterns:
c) fusedMultiplyAdd: fusedMultiplyAdd(0, ∞, c) or fusedMultiplyAdd(∞, 0, c)
unless c is a quiet NaN; if c is a quiet NaN then it is implementation
defined whether the invalid operation exception is signaled
d) addition or subtraction or fusedMultiplyAdd: magnitude subtraction of
infinities, such as: addition(+∞, −∞)
Differential Revision: https://reviews.llvm.org/D67446
llvm-svn: 371735
Summary:
I don't have a direct motivational case for this,
but it would be good to have this for completeness/symmetry.
This pattern is basically the motivational pattern from
https://bugs.llvm.org/show_bug.cgi?id=43251
but with different predicate that requires that the offset is non-zero.
The completeness bit comes from the fact that a similar pattern (offset != zero)
will be needed for https://bugs.llvm.org/show_bug.cgi?id=43259,
so it'd seem to be good to not overlook very similar patterns..
Proofs: https://rise4fun.com/Alive/21b
Also, there is something odd with `isKnownNonZero()`, if the non-zero
knowledge was specified as an assumption, it didn't pick it up (PR43267)
Reviewers: spatel, nikic, xbolva00
Reviewed By: spatel
Subscribers: hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D67411
llvm-svn: 371718
When possible, replace calls to library routines on the host with equivalent
ones in LLVM.
Differential revision: https://reviews.llvm.org/D67459
llvm-svn: 371677
This was actually the original intention in D67332,
but i messed up and forgot about it.
This patch was originally part of D67411, but precommitting this.
llvm-svn: 371630
Configure TLI to say that r600/amdgpu does not have any library
functions, such that InstCombine does not do anything like turn sin/cos
into the library function @tan with sufficient fast math flags.
Differential Revision: https://reviews.llvm.org/D67406
Change-Id: I02f907d3e64832117ea9800e9f9285282856e5df
llvm-svn: 371592
Summary:
Do not model debuginfo intrinsics in MemorySSA.
Regularly these are non-memory modifying instructions. With -disable-basicaa, they were being modelled as Defs.
Reviewers: george.burgess.iv
Subscribers: aprantl, Prazek, sanjoy.google, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D67307
llvm-svn: 371565
Expose a utility function so that all places which want to suppress speculation (when otherwise legal) due to ordering and/or sanitizer interaction can do so.
llvm-svn: 371556
Since NaN is very rare in normal programs, so the probability for floating point unordered comparison should be extremely small. Current probability is 3/8, it is too large, this patch changes it to a tiny number.
Differential Revision: https://reviews.llvm.org/D65303
llvm-svn: 371541
Summary:
This is motivated by D67122 sanitizer check enhancement.
That patch seemingly worsens `-fsanitize=pointer-overflow`
overhead from 25% to 50%, which strongly implies missing folds.
In this particular case, given
```
char* test(char& base, unsigned long offset) {
return &base + offset;
}
```
it will end up producing something like
https://godbolt.org/z/LK5-iH
which after optimizations reduces down to roughly
```
define i1 @t0(i8* nonnull %base, i64 %offset) {
%base_int = ptrtoint i8* %base to i64
%adjusted = add i64 %base_int, %offset
%non_null_after_adjustment = icmp ne i64 %adjusted, 0
%no_overflow_during_adjustment = icmp uge i64 %adjusted, %base_int
%res = and i1 %non_null_after_adjustment, %no_overflow_during_adjustment
ret i1 %res
}
```
Without D67122 there was no `%non_null_after_adjustment`,
and in this particular case we can get rid of the overhead:
Here we add some offset to a non-null pointer,
and check that the result does not overflow and is not a null pointer.
But since the base pointer is already non-null, and we check for overflow,
that overflow check will already catch the null pointer,
so the separate null check is redundant and can be dropped.
Alive proofs:
https://rise4fun.com/Alive/WRzq
There are more patterns of "unsigned-add-with-overflow", they are not handled here,
but this is the main pattern, that we currently consider canonical,
so it makes sense to handle it.
https://bugs.llvm.org/show_bug.cgi?id=43246
Reviewers: spatel, nikic, vsk
Reviewed By: spatel
Subscribers: hiraditya, llvm-commits, reames
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D67332
llvm-svn: 371349
Summary:
Add an intrinsic that takes 2 unsigned integers with
the scale of them provided as the third argument and
performs fixed point multiplication on them. The
result is saturated and clamped between the largest and
smallest representable values of the first 2 operands.
This is a part of implementing fixed point arithmetic
in clang where some of the more complex operations
will be implemented as intrinsics.
Patch by: leonardchan, bjope
Reviewers: RKSimon, craig.topper, bevinh, leonardchan, lebedev.ri, spatel
Reviewed By: leonardchan
Subscribers: ychen, wuzish, nemanjai, MaskRay, jsji, jdoerfert, Ka-Ka, hiraditya, rjmccall, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D57836
llvm-svn: 371308
