Remove assertion that disallows getting a zero-extended value from a
zero-width APInt. This check is too restrictive and makes it difficult
to use APInt to model zero-width things, e.g., zero-width wires in the
CIRCT project.
Signed-off-by: Schuyler Eldridge <schuyler.eldridge@sifive.com>
Reviewed By: lattner, darthscsi, nikic
Differential Revision: https://reviews.llvm.org/D114768
Inspired by D111968, provide a isNegatedPowerOf2() wrapper instead of obfuscating code with (-Value).isPowerOf2() patterns, which I'm sure are likely avenues for typos.....
Differential Revision: https://reviews.llvm.org/D111998
The sdiv used to check for overflow can itself overflow if the
LHS is signed min and the RHS is -1. The code tried to account for
this by also checking the commuted version. However, for 1-bit
values, signed min and -1 are the same value, so both divisions
overflow. As such, the overflow for -1 * -1 was not detected
(which results in -1 rather than 1 for 1-bit values). Fix this by
explicitly checking for this case instead.
Noticed while adding exhaustive test coverage for smul_ov(),
which is also part of this commit.
isAllOnes() should return true for zero bit values because
there are no zeros in it.
Thanks to Jay Foad for pointing this out.
Differential Revision: https://reviews.llvm.org/D111241
These should both clearly work with our current model for zero width
integers, but don't until now!
Differential Revision: https://reviews.llvm.org/D111113
Three unrelated changes:
1) Add a concat method as a convenience to help write bitvector
use cases in a nicer way.
2) Use LLVM_UNLIKELY as suggested by @xbolva00 in a previous patch.
3) Fix casing of some "slow" methods to follow naming standards.
Differential Revision: https://reviews.llvm.org/D109620
APInt is used to describe a bit mask in a variety of value tracking and demanded bits/elts functions.
When traversing through dst/src operands, we have a number of places where these masks need to widened/narrowed to translate through bitcasts, reductions etc. to a different type.
This patch add a APIntOps::ScaleBitMask common helper, adds unit test coverage, and updates a number of cases to use the the helper instead of their own implementation.
This came up on D109065 where we currently have to add yet another implementation of the same code.
Differential Revision: https://reviews.llvm.org/D109683
Motivation: APInt not supporting zero bit values leads to
a lot of special cases in various bits of code, particularly
when using APInt as a bit vector (where you want to start with
zero bits and then concat on more. This is particularly
challenging in the CIRCT project, where the absence of zero-bit
ConstantOp forces duplication of ops and makes instcombine-like
logic far more complicated.
Approach: zero bit integers are weird. There are two reasonable
approaches: either make it illegal to do general arithmetic on
them (e.g. sign extends), or treat them as as implicitly having
a zero value. This patch takes the conservative approach, which
enables their use in bitvector applications.
Differential Revision: https://reviews.llvm.org/D109555
This renames the primary methods for creating a zero value to `getZero`
instead of `getNullValue` and renames predicates like `isAllOnesValue`
to simply `isAllOnes`. This achieves two things:
1) This starts standardizing predicates across the LLVM codebase,
following (in this case) ConstantInt. The word "Value" doesn't
convey anything of merit, and is missing in some of the other things.
2) Calling an integer "null" doesn't make any sense. The original sin
here is mine and I've regretted it for years. This moves us to calling
it "zero" instead, which is correct!
APInt is widely used and I don't think anyone is keen to take massive source
breakage on anything so core, at least not all in one go. As such, this
doesn't actually delete any entrypoints, it "soft deprecates" them with a
comment.
Included in this patch are changes to a bunch of the codebase, but there are
more. We should normalize SelectionDAG and other APIs as well, which would
make the API change more mechanical.
Differential Revision: https://reviews.llvm.org/D109483
This moves one mid-size function out of line, inlines the
trivial tcAnd/tcOr/tcXor/tcComplement methods into their only
caller, and moves the magic/umagic functions into SelectionDAG
since they are implementation details of its algorithm. This
also removes the unit tests for magic, but these are already
tested in the divide lowering logic for various targets.
This also upgrades some C style comments to C++.
Differential Revision: https://reviews.llvm.org/D109476
<string> is currently the highest impact header in a clang+llvm build:
https://commondatastorage.googleapis.com/chromium-browser-clang/llvm-include-analysis.html
One of the most common places this is being included is the APInt.h header, which needs it for an old toString() implementation that returns std::string - an inefficient method compared to the SmallString versions that it actually wraps.
This patch replaces these APInt/APSInt methods with a pair of llvm::toString() helpers inside StringExtras.h, adjusts users accordingly and removes the <string> from APInt.h - I was hoping that more of these users could be converted to use the SmallString methods, but it appears that most end up creating a std::string anyhow. I avoided trying to use the raw_ostream << operators as well as I didn't want to lose having the integer radix explicit in the code.
Differential Revision: https://reviews.llvm.org/D103888
Truncates the APInt if the bit width is greater than the width specified,
otherwise do nothing
Reviewed By: RKSimon
Differential Revision: https://reviews.llvm.org/D91445
As noted on D74621, the bswap intrinsic has a self imposed limitation that the type's bitwidth must be divisible by 16, but there's no reason that APInt::byteSwap must have the same limitation, given that it can already handle any byte width.
Summary:
The signed one is needed for implementation of `ConstantRange::smul_sat()`,
unsigned is for completeness only.
Reviewers: nikic, RKSimon, spatel
Reviewed By: nikic
Subscribers: hiraditya, dexonsmith, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D69993
Summary:
Compare two values, and if they are different, return the position of the
most significant bit that is different in the values.
Needed for D69387.
Reviewers: nikic, spatel, sanjoy, RKSimon
Reviewed By: nikic
Subscribers: xbolva00, hiraditya, dexonsmith, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D69439
Summary:
There are `*_ov()` functions already, so at least for consistency it may be good to also have saturating variants.
These may or may not be needed for `ConstantRange`'s `shlWithNoWrap()`
Reviewers: spatel, nikic
Reviewed By: nikic
Subscribers: hiraditya, dexonsmith, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D69398
Summary:
There are `*_ov()` functions already, so at least for consistency it may be good to also have saturating variants.
These may or may not be needed for `ConstantRange`'s `mulWithNoWrap()`
Reviewers: spatel, nikic
Reviewed By: nikic
Subscribers: hiraditya, dexonsmith, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D69397
Summary:
Also fixup rL371928 for cases that occur on our out-of-tree backend
There were still quite a few intermediate APInts and this caused the
compile time of MCCodeEmitter for our target to jump from 16s up to
~5m40s. This patch, brings it back down to ~17s by eliminating pretty
much all of them using two new APInt functions (extractBitsAsZExtValue(),
insertBits() but with a uint64_t). The exact conditions for eliminating
them is that the field extracted/inserted must be <=64-bit which is
almost always true.
Note: The two new APInt API's assume that APInt::WordSize is at least
64-bit because that means they touch at most 2 APInt words. They
statically assert that's true. It seems very unlikely that someone
is patching it to be smaller so this should be fine.
Reviewers: jmolloy
Reviewed By: jmolloy
Subscribers: hiraditya, dexonsmith, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D67686
llvm-svn: 372243
Without the fix gcc (7.4.0) complains with
../unittests/ADT/APIntTest.cpp: In member function 'virtual void {anonymous}::APIntTest_MultiplicativeInverseExaustive_Test::TestBody()':
../unittests/ADT/APIntTest.cpp:2510:36: error: comparison between signed and unsigned integer expressions [-Werror=sign-compare]
for (unsigned Value = 0; Value < (1 << BitWidth); ++Value) {
~~~~~~^~~~~~~~~~~~~~~~~
llvm-svn: 364624
Change two costly udiv() calls to lshr(1)*RHS + left-shift + plus
On one 64-bit umul_ov benchmark, I measured an obvious improvement: 12.8129s -> 3.6257s
Note, there may be some value to special case 64-bit (the most common
case) with __builtin_umulll_overflow().
Differential Revision: https://reviews.llvm.org/D60669
llvm-svn: 358730
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
This adds the sadd_sat, uadd_sat, ssub_sat, usub_sat methods for performing saturating additions and subtractions to APInt.
Split out from D54237.
Patch by: nikic (Nikita Popov)
Differential Revision: https://reviews.llvm.org/D54332
llvm-svn: 347324
Some trivial cases in udivrem were handled by directly assigning 0 or 1
to APInt objects. This would set the bit width to 1, instead of the bit
width of the inputs. A potentially undesirable side effect of that is
that with the bit width of 1, 1 equals -1.
Differential Revision: https://reviews.llvm.org/D49554
llvm-svn: 337478
Summary:
It was removed about a year ago in r300477. Bring it back, along with
its unittest, when the MSVC STL is in use. The MSVC STL performs
self-assignment in std::shuffle. These days, llvm::sort calls
std::shuffle when expensive checks are enabled to help find
non-determinism bugs.
Reviewers: craig.topper, chandlerc
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D46028
llvm-svn: 330776
Summary: extractBits assumes that `!this->isSingleWord() implies !Result.isSingleWord()`, which may not necessarily be true. Handle both cases.
Reviewers: RKSimon
Subscribers: sanjoy, llvm-commits, hiraditya
Differential Revision: https://reviews.llvm.org/D43363
llvm-svn: 325311
Summary:
This patch adds udiv/sdiv/urem/srem/udivrem/sdivrem methods that can divide by a uint64_t. This makes division consistent with all the other arithmetic operations.
This modifies the interface of the divide helper method to work on raw arrays instead of APInts. This way we can pass the uint64_t in for the RHS without wrapping it in an APInt. This required moving all the Quotient and Remainder allocation handling up to the callers. For udiv/urem this was as simple as just creating the Quotient/Remainder with the right size when they were declared. For udivrem we have to rely on reallocate not changing the contents of the variable LHS or RHS is aliased with the Quotient or Remainder APInts. We also have to zero the upper bits of Remainder and Quotient that divide doesn't write to if lhsWords/rhsWords is smaller than the width.
I've update the toString method to use the new udivrem.
Reviewers: hans, dblaikie, RKSimon
Reviewed By: RKSimon
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D33310
llvm-svn: 303431
This features isn't used anywhere in tree. It's existence seems to be preventing selfhost builds from inlining any of the setBits methods including setLowBits, setHighBits, and setBitsFrom. This is because the code makes the method recursive.
If anyone needs this feature in the future we could consider adding a setBitsWithWrap method. This way only the calls that need it would pay for it.
llvm-svn: 301769
This patch adds an in place version of ashr to match lshr and shl which were recently added.
I've tried to make this similar to the lshr code with additions to handle the sign extension. I've also tried to do this with less if checks than the current ashr code by sign extending the original result to a word boundary before doing any of the shifting. This removes a lot of the complexity of determining where to fill in sign bits after the shifting.
Differential Revision: https://reviews.llvm.org/D32415
llvm-svn: 301198
Previously single word would always return 0 regardless of the original sign. Multi word would return all 0s or all 1s based on the original sign. Now single word takes into account the sign as well.
llvm-svn: 301159
