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
The previous commit had the condition in the do/while backwards.
Debug builds currently print out low level details of the Knuth division algorithm when -debug is used. This information isn't useful in most cases and just adds noise to the log.
This adds a new preprocessor flag to enable the prints in the knuth division code in APInt.
Differential Revision: https://reviews.llvm.org/D40404
llvm-svn: 318966
Debug builds currently print out low level details of the Knuth division algorithm when -debug is used. This information isn't useful in most cases and just adds noise to the log.
This adds a new preprocessor flag to enable the prints in the knuth division code in APInt.
Differential Revision: https://reviews.llvm.org/D40404
llvm-svn: 318963
Summary:
Add LLVM_FORCE_ENABLE_DUMP cmake option, and use it along with
LLVM_ENABLE_ASSERTIONS to set LLVM_ENABLE_DUMP.
Remove NDEBUG and only use LLVM_ENABLE_DUMP to enable dump methods.
Move definition of LLVM_ENABLE_DUMP from config.h to llvm-config.h so
it'll be picked up by public headers.
Differential Revision: https://reviews.llvm.org/D38406
llvm-svn: 315590
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
We already counted the number of bits in the RHS so its pretty cheap to just check if the RHS is 1.
Differential Revision: https://reviews.llvm.org/D33154
llvm-svn: 302953
This helped the compiler generate better code for the single word case. It was able to remember that the bit width was still a single word when it created the Remainder APInt and not create code for it possibly being multiword.
llvm-svn: 302952
At this point in the code rhsWords is guaranteed to be non-zero and less than or equal to lhsWords. So if lhsWords is 1, rhsWords must also be 1. urem alread had the check removed so this makes all 3 consistent.
llvm-svn: 302930
Summary:
This adds a resize method to APInt that manages deleting/allocating storage for an APInt and changes its bit width. Use this to simplify code in copy assignment and divide.
The assignment code in particular was overly complicated. Treating every possible case as a separate implementation. I'm also pretty sure the clearUnusedBits code at the end was unnecessary. Since we always copying whole words from the source APInt. All unused bits should be clear in the source.
Reviewers: hans, RKSimon
Reviewed By: RKSimon
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D33073
llvm-svn: 302863
This lets toString take advantage of the degenerate case checks in udivrem and is just generally cleaner.
One minor downside of this is that the divisor APInt now needs to be the same size as Tmp which requires an additional allocation. But we were doing a poor job of reusing allocations before so the new code should still be an improvement.
llvm-svn: 302704
The description says it returns the number of words needed to represent the results. But the way it was coded it always returns (lhsWords + rhsWords) or (lhsWords + rhsWords - 1). But the result could be even smaller than that and it wouldn't tell you.
No one uses the result today so rather than try to fix it, just remove it.
llvm-svn: 302551
The value of 'i' is always the smaller of DstParts and SrcParts so we can just use that fact to write all the code in terms of SrcParts and DstParts.
llvm-svn: 302408
Currently multiply is implemented in operator*=. Operator* makes a copy and uses operator*= to modify the copy.
Operator*= itself allocates a temporary buffer to hold the multiply result as it computes it. Then copies it to the buffer in *this.
Operator*= attempts to bound the size of the result based on the number of active bits in its inputs. It also has a couple special cases to handle 0 inputs without any memory allocations or multiply operations. The best case is that it calculates a single word regardless of input bit width. The worst case is that it calculates the a 2x input width result and drop the upper bits.
Since operator* uses operator*= it incurs two allocations, one for a copy of *this and one for the temporary allocation. Neither of these allocations are kept after the method operation is done.
The main usage in the backend appears to be ConstantRange::multiply which uses operator* rather than operator*=.
This patch moves the multiply operation to operator* and implements operator*= using it. This avoids the copy in operator*. operator* now allocates a result buffer sized the same width as its inputs no matter what. This buffer will be used as the buffer for the returned APInt. Finally, we reuse tcMultiply to implement the multiply operation. This function is capable of not calculating additional upper words that will be discarded.
This change does lose the special optimizations for the inputs using less words than their size implies. But it also removed the getActiveBits calls from all multiplies. If we think those optimizations are important we could look at providing additional bounds to tcMultiply to limit the computations.
Differential Revision: https://reviews.llvm.org/D32830
llvm-svn: 302171
Currently several places assume the VAL member is always at least the same size as pVal. In particular for a memcpy in the move assignment operator. While this is a true assumption, it isn't good practice to assume this.
This patch gives the union a name so we can write the memcpy in terms of the union itself. This also adds a similar memcpy to the move constructor where we previously just copied using VAL directly.
This patch is mostly just a mechanical addition of the U in front of VAL and pVAL everywhere. But several constructors had to be modified since we can't directly initializer a field of named union from the initializer list.
Differential Revision: https://reviews.llvm.org/D30629
llvm-svn: 302040
This replaces a hand written copy loop with a call to memcpy for both zext and sext.
For sext, it replaces multiple if/else blocks propagating sign information forward. Now we just do a copy, a sign extension on the last copied word, a memset, and clearUnusedBits.
Differential Revision: https://reviews.llvm.org/D32417
llvm-svn: 301201
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
This reverts commit r301105, 4, 3 and 1, as a follow up of the previous
revert, which broke even more bots.
For reference:
Revert "[APInt] Use operator<<= where possible. NFC"
Revert "[APInt] Use operator<<= instead of shl where possible. NFC"
Revert "[APInt] Use ashInPlace where possible."
PR32754.
llvm-svn: 301111
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
Currently sle and ule have to call slt/ult and eq to get the proper answer. This results in extra code for both calls and additional scans of multiword APInts.
This patch replaces slt/ult with a compareSigned/compare that can return -1, 0, or 1 so we can cover all the comparison functions with a single call.
While I was there I removed the activeBits calls and other checks at the start of the slow part of ult. Both of the activeBits calls potentially scan through each of the APInts separately. I can't imagine that's any better than just scanning them in parallel and doing the compares. Now we just share the code with tcCompare.
These changes seem to be good for about a 7-8k reduction on the size of the opt binary on my local x86-64 build.
Differential Revision: https://reviews.llvm.org/D32339
llvm-svn: 300995
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
Summary: This is a simple question we should be able to answer without creating a temporary to hold the AND result. We can also get an early out as soon as we find a word that intersects.
Reviewers: RKSimon, hans, spatel, davide
Reviewed By: hans, davide
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D32253
llvm-svn: 300812
This patch uses lshrInPlace to replace code where the object that lshr is called on is being overwritten with the result.
This adds an lshrInPlace(const APInt &) version as well.
Differential Revision: https://reviews.llvm.org/D32155
llvm-svn: 300566
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 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
Summary:
APInt is currently implemented with an unsigned BitWidth field first and then a uint_64/pointer union. Due to the 64-bit size of the union there is a hole after the bitwidth.
Putting the union first allows the class to be packed. Making it 12 bytes instead of 16 bytes. An APSInt goes from 20 bytes to 16 bytes.
This shows a 4k reduction on the size of the opt binary on my local x86-64 build. So this enables some other improvement to the code as well.
Reviewers: dblaikie, RKSimon, hans, davide
Reviewed By: davide
Subscribers: davide, llvm-commits
Differential Revision: https://reviews.llvm.org/D32001
llvm-svn: 300171
This patch is one step to attempt to unify the main APInt interface and the tc functions used by APFloat.
This patch adds a WordType to APInt and uses that in all the tc functions. I've added temporary typedefs to APFloat to alias it to integerPart to keep the patch size down. I'll work on removing that in a future patch.
In future patches I hope to reuse the tc functions to implement some of the main APInt functionality.
I may remove APINT_ from BITS_PER_WORD and WORD_SIZE constants so that we don't have the repetitive APInt::APINT_ externally.
Differential Revision: https://reviews.llvm.org/D31523
llvm-svn: 299341
Summary:
GreatestComonDivisor currently makes a copy of both its inputs. Then in the loop we do one move and two copies, plus any allocation the urem call does.
This patch changes it to take its inputs by value so that we can do a move of any rvalue inputs instead of copying. Then in the loop we do 3 move assignments and no copies. This way the only possible allocations we have in the loop is from the urem call.
Reviewers: dblaikie, RKSimon, hans
Reviewed By: dblaikie
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D31572
llvm-svn: 299314
This method is pretty new and probably isn't use much in the code base so this should have a negligible size impact. The OR and XOR operators are already inline.
llvm-svn: 298870
I'm not sure if zeroing VAL before writing pVal is really necessary, but at least one other place did it in code.
But by taking the store out of line, this reduces the opt binary by about 20k on my local x86-64 build.
llvm-svn: 298233
We currently have to insert bits via a temporary variable of the same size as the target with various shift/mask stages, resulting in further temporary variables, all of which require the allocation of memory for large APInts (MaskSizeInBits > 64).
This is another of the compile time issues identified in PR32037 (see also D30265).
This patch adds the APInt::insertBits() helper method which avoids the temporary memory allocation and masks/inserts the raw bits directly into the target.
Differential Revision: https://reviews.llvm.org/D30780
llvm-svn: 297458
This extends an earlier change that did similar for add and sub operations.
With this first patch we lose the fastpath for the single word case as operator&= and friends don't support it. This can be added there if we think that's important.
I had to change some functions in the APInt class since the operator overloads were moved out of the class and can't be used inside the class now. The getBitsSet change collides with another outstanding patch to implement it with setBits. But I didn't want to make this patch dependent on that series.
I've also removed the Or, And, Xor functions which were rarely or never used. I already commited two changes to remove the only uses of Or that existed.
Differential Revision: https://reviews.llvm.org/D30612
llvm-svn: 297121
Summary:
There are quite a few places in the code base that do something like the following to set the high or low bits in an APInt.
KnownZero |= APInt::getHighBitsSet(BitWidth, BitWidth - 1);
For BitWidths larger than 64 this creates a short lived APInt with malloced storage. I think it might even call malloc twice. Its better to just provide methods that can set the necessary bits without the temporary APInt.
I'll update usages that benefit in a separate patch.
Reviewers: majnemer, MatzeB, davide, RKSimon, hans
Reviewed By: hans
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D30525
llvm-svn: 297111
Summary:
This patch moves the clearUnusedBits calls into the two different initialization paths for APInt from a uint64_t. This allows the compiler to better optimize the clearing of the unused bits for the single word case. And it puts the clearing for the multi word case into the initSlowCase function to save code. In the common case of initializing with 0 this allows the clearing to be completely optimized out for the single word case.
On my local x86 build this is showing a ~45kb reduction in the size of the opt binary.
Reviewers: RKSimon, hans, majnemer, davide, MatzeB
Reviewed By: hans
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D30486
llvm-svn: 296677
The current pattern for extract bits in range is typically:
Mask.lshr(BitOffset).trunc(SubSizeInBits);
Which can be particularly slow for large APInts (MaskSizeInBits > 64) as they require the allocation of memory for the temporary variable.
This is another of the compile time issues identified in PR32037 (see also D30265).
This patch adds the APInt::extractBits() helper method which avoids the temporary memory allocation.
Differential Revision: https://reviews.llvm.org/D30336
llvm-svn: 296272
The current pattern for extract bits in range is typically:
Mask.lshr(BitOffset).trunc(SubSizeInBits);
Which can be particularly slow for large APInts (MaskSizeInBits > 64) as they require the allocation of memory for the temporary variable.
This is another of the compile time issues identified in PR32037 (see also D30265).
This patch adds the APInt::extractBits() helper method which avoids the temporary memory allocation.
Differential Revision: https://reviews.llvm.org/D30336
llvm-svn: 296147
The current pattern for extract bits in range is typically:
Mask.lshr(BitOffset).trunc(SubSizeInBits);
Which can be particularly slow for large APInts (MaskSizeInBits > 64) as they require the allocation of memory for the temporary variable.
This is another of the compile time issues identified in PR32037 (see also D30265).
This patch adds the APInt::extractBits() helper method which avoids the temporary memory allocation.
Differential Revision: https://reviews.llvm.org/D30336
llvm-svn: 296141
The current pattern for setting bits in range is typically:
Mask |= APInt::getBitsSet(MaskSizeInBits, LoPos, HiPos);
Which can be particularly slow for large APInts (MaskSizeInBits > 64) as they require the allocation memory for the temporary variable.
This is one of the key compile time issues identified in PR32037.
This patch adds the APInt::setBits() helper method which avoids the temporary memory allocation completely, this first implementation uses setBit() internally instead but already significantly reduces the regression in PR32037 (~10% drop). Additional optimization may be possible.
I investigated whether there is need for APInt::clearBits() and APInt::flipBits() equivalents but haven't seen these patterns to be particularly common, but reusing the code would be trivial.
Differential Revision: https://reviews.llvm.org/D30265
llvm-svn: 296102
Hiroshi Inoue