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
