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
