be both simpler and substantially more efficient.
Rather than use a hand-rolled iteration technique that isn't quite the
same as RPO, use the pre-built RPO loop body traversal utility.
Once visiting the loop body in RPO, we can assert that we visit defs
before uses reliably. When this is the case, the only need to iterate is
when simplifying a def that is used by a PHI node along a back-edge.
With this patch, the first pass over the loop body is just a complete
simplification of every instruction across the loop body. When we
encounter a use of a simplified instruction that stems from a PHI node
in the loop body that has already been visited (due to some cyclic CFG,
potentially the loop itself, or a nested loop, or unstructured control
flow), we recall that specific PHI node for the second iteration.
Nothing else needs to be preserved from iteration to iteration.
On the second and later iterations, only instructions known to have
simplified inputs are considered, each time starting from a set of PHIs
that had simplified inputs along the backedges.
Dead instructions are collected along the way, but deleted in a batch at
the end of each iteration making the iterations themselves substantially
simpler. This uses a new batch API for recursively deleting dead
instructions.
This alsa changes the routine to visit subloops. Because simplification
is fundamentally transitive, we may need to visit the entire loop body,
including subloops, to handle knock-on simplification.
I've added a basic test file that helps demonstrate that all of these
changes work. It includes both straight-forward loops with
simplifications as well as interesting PHI-structures, CFG-structures,
and a nested loop case.
Differential Revision: https://reviews.llvm.org/D47407
llvm-svn: 333461
Summary: It was fully replaced back in 2014, and the implementation was removed 11 months ago by r306797.
Reviewers: hfinkel, chandlerc, whitequark, deadalnix
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D47436
llvm-svn: 333378
This is a simple implementation of the unroll-and-jam classical loop
optimisation.
The basic idea is that we take an outer loop of the form:
for i..
ForeBlocks(i)
for j..
SubLoopBlocks(i, j)
AftBlocks(i)
Instead of doing normal inner or outer unrolling, we unroll as follows:
for i... i+=2
ForeBlocks(i)
ForeBlocks(i+1)
for j..
SubLoopBlocks(i, j)
SubLoopBlocks(i+1, j)
AftBlocks(i)
AftBlocks(i+1)
Remainder
So we have unrolled the outer loop, then jammed the two inner loops into
one. This can lead to a simpler inner loop if memory accesses can be shared
between the now-jammed loops.
To do this we have to prove that this is all safe, both for the memory
accesses (using dependence analysis) and that ForeBlocks(i+1) can move before
AftBlocks(i) and SubLoopBlocks(i, j).
Differential Revision: https://reviews.llvm.org/D41953
llvm-svn: 333358
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 plan had always been to move towards using this rather than so much
in-pass simplification within the loop pipeline, but we never got around
to it.... until only a couple months after it was removed due to disuse.
=/
This commit is just a pure revert of the removal. I will add tests and
do some basic cleanup in follow-up commits. Then I'll wire it into the
loop pass pipeline.
Differential Revision: https://reviews.llvm.org/D47353
llvm-svn: 333250
Summary:
In LICM, CFG could be changed in splitPredecessorsOfLoopExit(), which update
only DT and LoopInfo. Therefore, we should preserve only DT and LoopInfo specifically,
instead of all analyses that depend on the CFG (setPreservesCFG()).
This change should fix PR37323.
Reviewers: uabelho, davide, dberlin, Ka-Ka
Reviewed By: dberlin
Subscribers: mzolotukhin, bjope, mcrosier, llvm-commits
Differential Revision: https://reviews.llvm.org/D46775
llvm-svn: 333198
The ARM/ARM64 AESE and AESD instructions have a builtin XOR as the first step in
the instruction. Therefore, if the AES key is zero and the AES data was
previously XORed, it can be combined into a single instruction.
Differential Revision: https://reviews.llvm.org/D47239
Patch by Michael Brase!
llvm-svn: 333193
Summary:
It's internal to the VPlanHCFGBuilder and should not be visible outside of its
translation unit.
Reviewers: dcaballe, fhahn
Reviewed By: fhahn
Subscribers: rengolin, bollu, tschuett, llvm-commits, rkruppe
Differential Revision: https://reviews.llvm.org/D47312
llvm-svn: 333187
Summary:
If NaryReassociate succeed it will, when replacing the old instruction
with the new instruction, also recursively delete trivially
dead instructions from the old instruction. However, if the input to the
NaryReassociate pass contain dead code it is not save to recursively
delete trivially deadinstructions as it might lead to deleting the newly
created instruction.
This patch will fix the problem by using WeakVH to detect this
rare case, when the newly created instruction is dead, and it will then
restart the basic block iteration from the beginning.
This fixes pr37539
Reviewers: tra, meheff, grosser, sanjoy
Reviewed By: sanjoy
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D47139
llvm-svn: 333155
Summary:
StructurizeCFG::orderNodes basically uses a reverse post-order (RPO) traversal of the region list to get the order.
The only problem with it is that sometimes backedges for outer loops will be visited before backedges for inner loops.
To solve this problem, a loop depth based approach has been used to make sure all blocks in this loop has been visited
before moving on to outer loop.
However, we found a problem for a SubRegion which is a loop itself:
--> BB1 --> BB2 --> BB3 -->
In this case, BB2 is a SubRegion (loop), and thus its loopdepth is different than that of BB1 and BB3. This fact will lead
BB2 to be placed in the wrong order.
In this work, we treat the SubRegion as a special case and use its exit block to determine the loop and its depth
to guard the sorting.
Reviewers:
arsenm, jlebar
Differential Revision:
https://reviews.llvm.org/D46912
llvm-svn: 333111
Summary:
Finally fixes [[ https://bugs.llvm.org/show_bug.cgi?id=6773 | PR6773 ]].
Now that the backend is all done, we can finally fold it!
The canonical unfolded masked merge pattern is
```(x & m) | (y & ~m)```
There is a second, equivalent variant:
```(x | ~m) & (y | m)```
Only one of them (the or-of-and's i think) is canonical.
And if the mask is not a constant, we should fold it to:
```((x ^ y) & M) ^ y```
https://rise4fun.com/Alive/ndQw
Reviewers: spatel, craig.topper
Reviewed By: spatel
Subscribers: nicholas, RKSimon, llvm-commits
Differential Revision: https://reviews.llvm.org/D46814
llvm-svn: 333106
Summary: This patch adds a PDT constructor from Function and lets codes previously using a local class to do this use PostDominatorTree class directly.
Reviewers: davide, kuhar, grosser, dberlin
Reviewed By: kuhar
Author: NutshellySima
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D46709
llvm-svn: 333102
Now that the LLVM_DEBUG() macro landed on the various sub-projects
the DEBUG macro can be removed.
Also change the new uses of DEBUG to LLVM_DEBUG.
Differential Revision: https://reviews.llvm.org/D46952
llvm-svn: 333091
Loop unswitching makes substantial changes to a loop that can also affect cached
SCEV info in its outer loops as well, but it only cares to invalidate SCEV cache for the
innermost loop in case of full unswitching and does not invalidate anything at all in
case of trivial unswitching. As result, we may end up with incorrect data in cache.
Differential Revision: https://reviews.llvm.org/D46045
Reviewed By: mzolotukhin
llvm-svn: 333072
Also, produce the canonical IR abs (s<0) to be more efficient.
This is the libcall equivalent of the clang builtin change from:
rL333038
Pasting from that commit message:
The stdlib functions are defined in section 7.20.6.1 of the C standard with:
"If the result cannot be represented, the behavior is undefined."
That lets us mark the negation with 'nsw' because "sub i32 0, INT_MIN" would
be UB/poison.
llvm-svn: 333042
Summary: Previous patch does not care if a value is changed between calloc and strlen. This needs to be removed from InstCombine and maybe moved to DSE later after some rework.
Reviewers: efriedma
Reviewed By: efriedma
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D47218
llvm-svn: 333022
This patch fixes two bugs:
* test1: Previously assume(a >= 5) concluded that a == 5. That's only
valid for assume(a == 5)...
* test2: If operands were swapped, additional users were added to the
wrong cmp operand. This resulted in an "unsettled iteration"
assertion failure.
Patch by Nikita Popov
Differential Revision: https://reviews.llvm.org/D46974
llvm-svn: 333007
Summary:
When lowerswitch merge several cases into a new default block it's not
updating the PHI nodes accordingly. The code that update the PHI nodes
for the default edge only update the first entry and do not remove the
remaining ones, to make sure the number of entries match the number of
predecessors.
This is easily fixed by replacing the code that update the PHI node with
the already existing utility function for updating PHI nodes.
Reviewers: hans, reames, arsenm
Reviewed By: arsenm
Subscribers: wdng, llvm-commits
Differential Revision: https://reviews.llvm.org/D47055
llvm-svn: 332960
Summary:
In LoopVersioning::addPHINodes we need to iterate over all
users for a value "Inst", and if the user is outside of the
VersionedLoop we should replace the use of "Inst" by using
the value "PN" instead.
Replacing the use of "Inst" for a user of "Inst" also means
that Inst->users() is modified. So it is not safe to do the
replace while iterating over Inst->users() as we used to do.
This patch splits the task into two steps. First we iterate
over Inst->users() to find all users that should be updated.
Those users are saved into a local data structure on the stack.
And then, in the second step, we do the actual updates. This
time iterating over the local data structure.
Reviewers: mzolotukhin, anemet
Reviewed By: mzolotukhin
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D47134
llvm-svn: 332958
We can eliminate old value if bound_ctrl = 1 and row_mask = bank_mask = 0xf.
This is alternative implementation working with the intrinsic in InstCombine.
Original review for past-ISel optimization: D46570.
Differential Revision: https://reviews.llvm.org/D46596
llvm-svn: 332956
r332654 tried to fix an unused function warning with
a void cast. This approach worked for clang and gcc
but not for MSVC. This commit replaces the void cast
with the LLVM_ATTRIBUTE_USED approach.
llvm-svn: 332910
Change matchSelectPattern to return X and -X for ABS/NABS in a well defined order. Adjust EarlyCSE to account for this. Ensure the SPF result is some kind of min/max and not abs/nabs in one place in InstCombine that made me nervous.
Prevously we returned the two operands of the compare part of the abs pattern. The RHS is always going to be a 0i, 1 or -1 constant. This isn't a very meaningful thing to return for any one. There's also some freedom in the abs pattern as to what happens when the value is equal to 0. This freedom led to early cse failing to match when different constants were used in otherwise equivalent operations. By returning the input and its negation in a defined order we can ensure an exact match. This also makes sure both patterns use the exact same subtract instruction for the negation. I believe CSE should evebntually make this happen and properly merge the nsw/nuw flags. But I'm not familiar with CSE and what order it does things in so it seemed like it might be good to really enforce that they were the same.
Differential Revision: https://reviews.llvm.org/D47037
llvm-svn: 332865
r332654 was reverted due to an unused function warning in
release build. This commit includes the same code with the
warning silenced.
Differential Revision: https://reviews.llvm.org/D44338
llvm-svn: 332860
Summary:
This patch fixes PR37526 by simplifying the newly generated LoadInst
instructions. If the pointer address is a bitcast from the pointer to
the NewType, we can just remove this extra bitcast instead of creating
the new one. This fixes the PR37526 + may speed up the whole compilation
process.
Reviewers: spatel, RKSimon, hfinkel
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D47144
llvm-svn: 332855
We were previously using a DT in CVP through SimplifyQuery, but not requiring it in
the new pass manager. Hence it would crash if DT was not already available. This now
gets DT directly and plumbs it through to where it is used (instead of using it
through SQ).
llvm-svn: 332836
We already do this for min/max (see the blob above the diff),
so we should do the same for abs/nabs.
A sign-bit check (<s 0) is used as a predicate for other IR
transforms and it's likely the best for codegen.
This might solve the motivating cases for D47037 and D47041,
but I think those patches still make sense. We can't guarantee
this canonicalization if the icmp has more than one use.
Differential Revision: https://reviews.llvm.org/D47076
llvm-svn: 332819
In the patch rL329547, we have lifted the over-restrictive limitation on collected range
checks, allowing to work with range checks with the end of their range not being
provably non-negative. However it appeared that the non-negativity of this value was
assumed in the utility function `ClampedSubtract`. In particular, its reasoning is based
on the fact that `0 <= SINT_MAX - X`, which is not true if `X` is negative.
The function `ClampedSubtract` is only called twice, once with `X = 0` (which is OK)
and the second time with `X = IRC.getEnd()`, where we may now see the problem if
the end is actually a negative value. In this case, we may sometimes miscompile.
This patch is the conservative fix of the miscompile problem. Rather than rejecting
non-provably non-negative `getEnd()` values, we will check it for non-negativity in
runtime. For this, we use function `smax(smin(X, 0), -1) + 1` that is equal to `1` if `X`
is non-negative and is equal to 0 if `X` is negative. If we multiply `Begin, End` of safe
iteration space by this function calculated for `X = IRC.getEnd()`, we will get the original
`[Begin, End)` if `IRC.getEnd()` was non-negative (and, thus, `ClampedSubtract` worked
correctly) and the empty range `[0, 0)` in case if ` IRC.getEnd()` was negative.
So we in fact prohibit execution of the main loop if at least one of range checks was
made against a negative value (and we figured it out in runtime). It is still better than
what we have before (non-negativity had to be proved in compile time) and prevents
us from miscompile, however it is sometiles too restrictive for unsigned range checks
against a negative value (which in fact can be eliminated).
Once we re-implement `ClampedSubtract` in a way that it handles negative `X` correctly,
this limitation can be lifted, too.
Differential Revision: https://reviews.llvm.org/D46860
Reviewed By: samparker
llvm-svn: 332809
The evaluator goes through BB and creates global vars as temporary values to evaluate
results of LLVM instructions. It creates undef for alloca, however it assumes alloca
in addr space 0. If the next instruction is addrspace cast to 0, then we get an invalid
cast instruction.
This patch let the temp global var have an address space matching alloca addr space,
so that the valuation can be done.
Differential Revision: https://reviews.llvm.org/D47081
llvm-svn: 332794
Summary:
Floating point division by zero or even undef does not have undefined
behavior and may occur due to optimizations.
Fixes https://bugs.llvm.org/show_bug.cgi?id=37523.
Reviewers: kcc
Subscribers: hiraditya, llvm-commits
Differential Revision: https://reviews.llvm.org/D47085
llvm-svn: 332761
The introduced problem is:
llvm.src/lib/Transforms/Vectorize/VPlanVerifier.cpp:29:13: error: unused function 'hasDuplicates' [-Werror,-Wunused-function]
static bool hasDuplicates(const SmallVectorImpl<VPBlockBase *> &VPBlockVec) {
^
llvm-svn: 332747
Summary:
Fix a case where FoldBranchToCommonDest() would bail out from doing CSE
when encountering a debug intrinsic. Handle that by skipping past the
debug intrinsics.
Also, as a minor refactoring, rename checkCSEInPredecessor() to
tryCSEWithPredecessor() to make it a bit more clear that the function
may remove instructions.
Reviewers: fhahn, craig.topper, dblaikie, xbolva00
Reviewed By: fhahn, xbolva00
Subscribers: vsk, davide, llvm-commits
Differential Revision: https://reviews.llvm.org/D46635
llvm-svn: 332698
1. Define Myriad-specific ASan constants.
2. Add code to generate an outer loop that checks that the address is
in DRAM range, and strip the cache bit from the address. The
former is required because Myriad has no memory protection, and it
is up to the instrumentation to range-check before using it to
index into the shadow memory.
3. Do not add an unreachable instruction after the error reporting
function; on Myriad such function may return if the run-time has
not been initialized.
4. Add a test.
Differential Revision: https://reviews.llvm.org/D46451
llvm-svn: 332692
Summary:
- Add wasm personality function
- Re-categorize the existing `isFuncletEHPersonality()` function into
two different functions: `isFuncletEHPersonality()` and
`isScopedEHPersonality(). This becomes necessary as wasm EH uses scoped
EH instructions (catchswitch, catchpad/ret, and cleanuppad/ret) but not
outlined funclets.
- Changed some callsites of `isFuncletEHPersonality()` to
`isScopedEHPersonality()` if they are related to scoped EH IR-level
stuff.
Reviewers: majnemer, dschuff, rnk
Subscribers: jfb, sbc100, jgravelle-google, eraman, JDevlieghere, sunfish, llvm-commits
Differential Revision: https://reviews.llvm.org/D45559
llvm-svn: 332667
Patch #3 from VPlan Outer Loop Vectorization Patch Series #1
(RFC: http://lists.llvm.org/pipermail/llvm-dev/2017-December/119523.html).
Expected to be NFC for the current inner loop vectorization path. It
introduces the basic algorithm to build the VPlan plain CFG (single-level
CFG, no hierarchical CFG (H-CFG), yet) in the VPlan-native vectorization
path using VPInstructions. It includes:
- VPlanHCFGBuilder: Main class to build the VPlan H-CFG (plain CFG without nested regions, for now).
- VPlanVerifier: Main class with utilities to check the consistency of a H-CFG.
- VPlanBlockUtils: Main class with utilities to manipulate VPBlockBases in VPlan.
Reviewers: rengolin, fhahn, mkuper, mssimpso, a.elovikov, hfinkel, aprantl.
Differential Revision: https://reviews.llvm.org/D44338
llvm-svn: 332654
According to alive this is valid. I'm hoping to use this to make an assumption that the sign bit is zero after this sequence. The only way it wouldn't be is if the input was INT__MIN, but by preserving the flags we can make doing this to INT_MIN UB.
The nuw flags is weird because it creates such a contradiction that the original number would have to be positive meaning we could remove the select entirely, but we don't get that far.
Differential Revision: https://reviews.llvm.org/D46988
llvm-svn: 332623
entries to reach the target. Since these calls don't require type checks,
we can short-circuit them to their real targets.
Differential Revision: https://reviews.llvm.org/D46326
llvm-svn: 332610
Summary:
The verifier accepts PHI nodes with multiple entries for the
same basic block, as long as the value is the same.
As seen in PR37203, SROA did not handle such PHI nodes properly
when speculating loads over the PHI, since it inserted multiple
loads in the predecessor block and changed the PHI into having
multiple entries for the same basic block, but with different
values.
This patch teaches SROA to reuse the same speculated load for
each PHI duplicate entry in such situations.
Resolves: https://bugs.llvm.org/show_bug.cgi?id=37203
Reviewers: uabelho, chandlerc, hfinkel, bkramer, efriedma
Reviewed By: efriedma
Subscribers: dberlin, efriedma, llvm-commits
Differential Revision: https://reviews.llvm.org/D46426
llvm-svn: 332577
The current integer widening does not support rewriting partial split slices in rewriteIntegerStore (and rewriteIntegerLoad).
This patch adds explicit checks for this case in isIntegerWideningViableForSlice.
Before r322533, splitting is allowed only for the whole-alloca slice and hence the above case is implicitly rejected by another check `if (DL.getTypeStoreSize(ValueTy) > Size)` because whole-alloca slice is larger than the partition.
Differential Revision: https://reviews.llvm.org/D46750
llvm-svn: 332575
