This adds the NAN checks suggested in PR37776:
https://bugs.llvm.org/show_bug.cgi?id=37776
If both operands to maxnum are NAN, that should get constant folded, so we don't
have to handle that case. This is the same assumption as other FP ops in this
function. Returning 'false' is always conservatively correct.
Copying from the bug report:
Currently, we have this for "when is cannotBeOrderedLessThanZero
(mustBePositiveOrNaN) true for maxnum":
L
-------------------
| Pos | Neg | NaN |
------------------------
|Pos | x | x | x |
------------------------
R |Neg | x | | x |
------------------------
|NaN | x | x | x |
------------------------
The cases with (Neg & NaN) are wrong. We should have:
L
-------------------
| Pos | Neg | NaN |
------------------------
|Pos | x | x | x |
------------------------
R |Neg | x | | |
------------------------
|NaN | x | | x |
------------------------
Differential Revision: https://reviews.llvm.org/D50081
llvm-svn: 338716
Currently ComputeNumSignBits does early exit while processing some
of the operations (add, sub, mul, and select). This prevents the
function from using AssumptionCacheTracker if passed.
Differential Revision: https://reviews.llvm.org/D49759
llvm-svn: 337936
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
It's a bit neater to write T.isIntOrPtrTy() over `T.isIntegerTy() ||
T.isPointerTy()`.
I used Python's re.sub with this regex to update users:
r'([\w.\->()]+)isIntegerTy\(\)\s*\|\|\s*\1isPointerTy\(\)'
llvm-svn: 336462
Summary:
This patch introduce new intrinsic -
strip.invariant.group that was described in the
RFC: Devirtualization v2
Reviewers: rsmith, hfinkel, nlopes, sanjoy, amharc, kuhar
Subscribers: arsenm, nhaehnle, JDevlieghere, hiraditya, xbolva00, llvm-commits
Differential Revision: https://reviews.llvm.org/D47103
Co-authored-by: Krzysztof Pszeniczny <krzysztof.pszeniczny@gmail.com>
llvm-svn: 336073
When checking a select to see if it matches an abs, allow the true/false values
to be a sign-extension of the comparison value instead of requiring that they're
directly the comparison value, as all the comparison cares about is the sign of
the value.
This fixes a regression due to r333702, where we were no longer generating ctlz
due to isKnownNonNegative failing to match such a pattern.
Differential Revision: https://reviews.llvm.org/D47631
llvm-svn: 333927
Summary:
The isKnownNonZero() function have checks that abort the recursion when
it reaches the specified max depth. However one of the recursive calls
was placed before the max depth check was done, resulting in a endless
recursion that eventually triggered a segmentation fault.
Fixed the problem by moving the max depth check above the first
recursive call.
Reviewers: Prazek, nlopes, spatel, craig.topper, hfinkel
Reviewed By: hfinkel
Subscribers: hfinkel, bjope, llvm-commits
Differential Revision: https://reviews.llvm.org/D47531
llvm-svn: 333557
Libfuzzer tests have been fixed to prevent being optimized.
Original commit message:
If the nsw flag is used in the absolute value then it is undefined for INT_MIN. For all other value it will produce a positive number. So we can assume the result is positive.
This breaks some InstCombine abs/nabs combining tests because we simplify the second compare from known bits rather than as the whole pattern. Looks like we can probably fix it by adding a neg+abs/nabs combine to just swap the select operands. N
Differential Revision: https://reviews.llvm.org/D47041
llvm-svn: 333300
If the nsw flag is used in the absolute value then it is undefined for INT_MIN. For all other value it will produce a positive number. So we can assume the result is positive.
This breaks some InstCombine abs/nabs combining tests because we simplify the second compare from known bits rather than as the whole pattern. Looks like we can probably fix it by adding a neg+abs/nabs combine to just swap the select operands. Need to check alive to make sure there are no corner cases.
Differential Revision: https://reviews.llvm.org/D47041
llvm-svn: 333226
Summary:
Patch for capture tracking broke
bootstrap of clang with -fstict-vtable-pointers
which resulted in debbugging nightmare. It was fixed
https://reviews.llvm.org/D46900 but as it turned
out, there were other parts like inliner (computing of
noalias metadata) that I found after bootstraping with enabled
assertions.
Reviewers: hfinkel, rsmith, chandlerc, amharc, kuhar
Subscribers: JDevlieghere, eraman, llvm-commits, hiraditya
Differential Revision: https://reviews.llvm.org/D47088
llvm-svn: 333070
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
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
Summary:
invariant.group.launder should not stop propagation
of nonnull and dereferenceable, because e.g. we would not be
able to hoist loads speculatively.
Reviewers: rsmith, amharc, kuhar, xbolva00, hfinkel
Subscribers: hiraditya, llvm-commits
Differential Revision: https://reviews.llvm.org/D46972
llvm-svn: 332788
In order to set breakpoints on labels and list source code around
labels, we need collect debug information for labels, i.e., label
name, the function label belong, line number in the file, and the
address label located. In order to keep these information in LLVM
IR and to allow backend to generate debug information correctly.
We create a new kind of metadata for labels, DILabel. The format
of DILabel is
!DILabel(scope: !1, name: "foo", file: !2, line: 3)
We hope to keep debug information as much as possible even the
code is optimized. So, we create a new kind of intrinsic for label
metadata to avoid the metadata is eliminated with basic block.
The intrinsic will keep existing if we keep it from optimized out.
The format of the intrinsic is
llvm.dbg.label(metadata !1)
It has only one argument, that is the DILabel metadata. The
intrinsic will follow the label immediately. Backend could get the
label metadata through the intrinsic's parameter.
We also create DIBuilder API for labels to be used by Frontend.
Frontend could use createLabel() to allocate DILabel objects, and use
insertLabel() to insert llvm.dbg.label intrinsic in LLVM IR.
Differential Revision: https://reviews.llvm.org/D45024
Patch by Hsiangkai Wang.
llvm-svn: 331841
We've been running doxygen with the autobrief option for a couple of
years now. This makes the \brief markers into our comments
redundant. Since they are a visual distraction and we don't want to
encourage more \brief markers in new code either, this patch removes
them all.
Patch produced by
for i in $(git grep -l '\\brief'); do perl -pi -e 's/\\brief //g' $i & done
Differential Revision: https://reviews.llvm.org/D46290
llvm-svn: 331272
Summary:
Currently, we
1. match `LHS` matcher to the `first` operand of binary operator,
2. and then match `RHS` matcher to the `second` operand of binary operator.
If that does not match, we swap the `LHS` and `RHS` matchers:
1. match `RHS` matcher to the `first` operand of binary operator,
2. and then match `LHS` matcher to the `second` operand of binary operator.
This works ok.
But it complicates writing of commutative matchers, where one would like to match
(`m_Value()`) the value on one side, and use (`m_Specific()`) it on the other side.
This is additionally complicated by the fact that `m_Specific()` stores the `Value *`,
not `Value **`, so it won't work at all out of the box.
The last problem is trivially solved by adding a new `m_c_Specific()` that stores the
`Value **`, not `Value *`. I'm choosing to add a new matcher, not change the existing
one because i guess all the current users are ok with existing behavior,
and this additional pointer indirection may have performance drawbacks.
Also, i'm storing pointer, not reference, because for some mysterious-to-me reason
it did not work with the reference.
The first one appears trivial, too.
Currently, we
1. match `LHS` matcher to the `first` operand of binary operator,
2. and then match `RHS` matcher to the `second` operand of binary operator.
If that does not match, we swap the ~~`LHS` and `RHS` matchers~~ **operands**:
1. match ~~`RHS`~~ **`LHS`** matcher to the ~~`first`~~ **`second`** operand of binary operator,
2. and then match ~~`LHS`~~ **`RHS`** matcher to the ~~`second`~ **`first`** operand of binary operator.
Surprisingly, `$ ninja check-llvm` still passes with this.
But i expect the bots will disagree..
The motivational unittest is included.
I'd like to use this in D45664.
Reviewers: spatel, craig.topper, arsenm, RKSimon
Reviewed By: craig.topper
Subscribers: xbolva00, wdng, llvm-commits
Differential Revision: https://reviews.llvm.org/D45828
llvm-svn: 331085
Summary:
In order to get the whole fold as specified in [[ https://bugs.llvm.org/show_bug.cgi?id=6773 | PR6773 ]],
let's first handle the simple straight-forward things.
Let's start with the `and` -> `or` simplification.
The one obvious thing missing here: the constant mask is not handled.
I have an idea how to handle it, but it will require some thinking,
and is not strictly required here, so i've left that for later.
https://rise4fun.com/Alive/Pkmg
Reviewers: spatel, craig.topper, eli.friedman, jingyue
Reviewed By: spatel
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D45631
llvm-svn: 330101
Most of the folds based on SelectPatternResult belong in InstSimplify rather than
InstCombine, so the helper code should be available to other passes/analysis.
llvm-svn: 326812
This is similar to what's done in computeKnownBits and computeSignBits. Don't do anything fancy just collect information valid for any element.
Differential Revision: https://reviews.llvm.org/D43789
llvm-svn: 326237
Making a width of GEP Index, which is used for address calculation, to be one of the pointer properties in the Data Layout.
p[address space]:size:memory_size:alignment:pref_alignment:index_size_in_bits.
The index size parameter is optional, if not specified, it is equal to the pointer size.
Till now, the InstCombiner normalized GEPs and extended the Index operand to the pointer width.
It works fine if you can convert pointer to integer for address calculation and all registered targets do this.
But some ISAs have very restricted instruction set for the pointer calculation. During discussions were desided to retrieve information for GEP index from the Data Layout.
http://lists.llvm.org/pipermail/llvm-dev/2018-January/120416.html
I added an interface to the Data Layout and I changed the InstCombiner and some other passes to take the Index width into account.
This change does not affect any in-tree target. I added tests to cover data layouts with explicitly specified index size.
Differential Revision: https://reviews.llvm.org/D42123
llvm-svn: 325102
The last assume in the test says that %B12 is 0.
The first assume says that %and1 is less than %B12.
Therefore, %and1 is unsigned less than 0...does not compute.
That means this line:
Known.Zero.setHighBits(RHSKnown.countMinLeadingZeros() + 1);
...tries to set more bits than exist.
Differential Revision: https://reviews.llvm.org/D43052
llvm-svn: 324610
Generalize existing constant matching to work with non-uniform constant vectors as well.
Differential Revision: https://reviews.llvm.org/D42818
llvm-svn: 324369
We're getting bug reports:
https://bugs.llvm.org/show_bug.cgi?id=35807https://bugs.llvm.org/show_bug.cgi?id=35840https://bugs.llvm.org/show_bug.cgi?id=36045
...where we blow up the stack in value tracking because other passes are sending
in selects that have an operand that is itself the select.
We don't currently have a reliable way to avoid analyzing dead code that may take
non-standard forms, so bail out when things go too far.
This mimics the recursion depth limitations in other parts of value tracking.
Unfortunately, this pushes the underlying problems for other passes (jump-threading,
simplifycfg, correlated-propagation) into hiding. If someone wants to uncover those
again, the first draft of this patch on Phab would do that (it would assert rather
than bail out).
Differential Revision: https://reviews.llvm.org/D42442
llvm-svn: 323331
This was originally planned as the fix for:
https://bugs.llvm.org/show_bug.cgi?id=35834
...but simpler transforms handled that case, so I implemented a
lesser solution. It turns out we need to handle the case with 'not'
ops too because the real code example that we are trying to solve:
https://bugs.llvm.org/show_bug.cgi?id=35875
...has extra uses of the intermediate values, so we can't rely on
smaller canonicalizations to get us to the goal.
As with rL321672, I've tried to show every possibility in the
codegen tests because that's the simplest way to prove we're doing
the right thing in the wide variety of permutations of this pattern.
We can also show an InstCombine win because we added a fold for
this case in:
rL321998 / D41603
An Alive proof for one variant of the pattern to show that the
InstCombine and codegen results are correct:
https://rise4fun.com/Alive/vd1
Name: min3_nots
%nx = xor i8 %x, -1
%ny = xor i8 %y, -1
%nz = xor i8 %z, -1
%cmpxz = icmp slt i8 %nx, %nz
%minxz = select i1 %cmpxz, i8 %nx, i8 %nz
%cmpyz = icmp slt i8 %ny, %nz
%minyz = select i1 %cmpyz, i8 %ny, i8 %nz
%cmpyx = icmp slt i8 %y, %x
%r = select i1 %cmpyx, i8 %minxz, i8 %minyz
=>
%cmpxyz = icmp slt i8 %minxz, %ny
%r = select i1 %cmpxyz, i8 %minxz, i8 %ny
Name: min3_nots_alt
%nx = xor i8 %x, -1
%ny = xor i8 %y, -1
%nz = xor i8 %z, -1
%cmpxz = icmp slt i8 %nx, %nz
%minxz = select i1 %cmpxz, i8 %nx, i8 %nz
%cmpyz = icmp slt i8 %ny, %nz
%minyz = select i1 %cmpyz, i8 %ny, i8 %nz
%cmpyx = icmp slt i8 %y, %x
%r = select i1 %cmpyx, i8 %minxz, i8 %minyz
=>
%xz = icmp sgt i8 %x, %z
%maxxz = select i1 %xz, i8 %x, i8 %z
%xyz = icmp sgt i8 %maxxz, %y
%maxxyz = select i1 %xyz, i8 %maxxz, i8 %y
%r = xor i8 %maxxyz, -1
llvm-svn: 322283
This is a preliminary step for the patch discussed in D41136 (and denoted here with the FIXME comment).
When we match an FP min/max that is cast to integer, any intermediate difference between +0.0 or -0.0
should be muted in the result by the conversion (either fptosi or fptoui) of the result. Thus, we can
enable 'nsz' for the purpose of matching fmin/fmax.
Note that there's probably room to generalize this more, possibly by fixing the current calls to the
weak version of isKnownNonZero() in matchSelectPattern() to the more powerful recursive version.
Differential Revision: https://reviews.llvm.org/D41333
llvm-svn: 321456
SROA analysis of InlineCost can figure out that some stores can be removed
after inlining and then the repeated loads clobbered by these stores are also
free. This patch finds these clobbered loads and adjust the inline cost
accordingly.
Differential Revision: https://reviews.llvm.org/D33946
llvm-svn: 320814
When the lowest bits of the operands to an integer multiply are known, the low bits of the result are deducible.
Code to deduce known-zero bottom bits already existed, but this change improves on that by deducing known-ones.
Patch by: Pedro Ferreira
Reviewers: craig.topper, sanjoy, efriedma
Differential Revision: https://reviews.llvm.org/D34029
llvm-svn: 320269
Summary:
This is LLVM instrumentation for the new HWASan tool. It is basically
a stripped down copy of ASan at this point, w/o stack or global
support. Instrumenation adds a global constructor + runtime callbacks
for every load and store.
HWASan comes with its own IR attribute.
A brief design document can be found in
clang/docs/HardwareAssistedAddressSanitizerDesign.rst (submitted earlier).
Reviewers: kcc, pcc, alekseyshl
Subscribers: srhines, mehdi_amini, mgorny, javed.absar, eraman, llvm-commits, hiraditya
Differential Revision: https://reviews.llvm.org/D40932
llvm-svn: 320217
