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
The current code is trying to be clever with shifts to avoid needing to clear unused bits. But it looks like the compiler is unable to optimize out the unused bit handling in the APInt constructor. Given this its better to just use SignExtend64 and have more readable code.
llvm-svn: 301133
For single word, shift by BitWidth was always returning 0, but for multiword it was based on original sign. Now single word matches multi word.
llvm-svn: 301094
This question comes up in many places in SimplifyDemandedBits. This makes it easy to ask without allocating additional temporary APInts.
The BitVector class provides a similar functionality through its (IMHO badly named) test(const BitVector&) method. Though its output polarity is reversed.
I've provided one example use case in this patch. I plan to do more as a follow up.
Differential Revision: https://reviews.llvm.org/D32258
llvm-svn: 300851
This merges the two different multiword shift right implementations into a single version located in tcShiftRight. lshrInPlace now calls tcShiftRight for the multiword case.
I retained the memmove fast path from lshrInPlace and used a memset for the zeroing. The for loop is basically tcShiftRight's implementation with the zeroing and the intra-shift of 0 removed.
Differential Revision: https://reviews.llvm.org/D32114
llvm-svn: 300503
This was added to work around a bug in MSVC 2013's implementation of stable_sort. That bug has been fixed as of MSVC 2015 so we shouldn't need this anymore.
Technically the current implementation has undefined behavior because we only protect the deleting of the pVal array with the self move check. There is still a memcpy of that.VAL to VAL that isn't protected. In the case of self move those are the same local and memcpy is undefined for src and dst overlapping.
This reduces the size of the opt binary on my local x86-64 build by about 4k.
Differential Revision: https://reviews.llvm.org/D32116
llvm-svn: 300477
This was throwing an assert because we determined the intra-word shift amount by subtracting the size of the full word shift from the total shift amount. But we failed to account for the fact that we clipped the full word shifts by total words first. To fix this just calculate the intra-word shift as the remainder of dividing by bits per word.
llvm-svn: 300405
Switch from Euclid's algorithm to Stein's algorithm for computing GCD. This
avoids the (expensive) APInt division operation in favour of bit operations.
Remove all memory allocation from within the GCD loop by tweaking our `lshr`
implementation so it can operate in-place.
Differential Revision: https://reviews.llvm.org/D31968
llvm-svn: 300252
This moves the isMask and isShiftedMask functions to be class methods. They now use the MathExtras.h function for single word size and leading/trailing zeros/ones or countPopulation for the multiword size. The previous implementation made multiple temorary memory allocations to do the bitwise arithmetic operations to match the MathExtras.h implementation.
Differential Revision: https://reviews.llvm.org/D31565
llvm-svn: 299362
