the bit width of negative numbers by computing the minimum bit width for a
negative value. E.g. 0x1800000000000000 could be just 0x8000000000000000
llvm-svn: 34695
1. Add unsigned and signed versions of methods so a "bool" argument doesn't
need to be passed in.
2. Make the various getMin/getMax functions all be inline since they are
so simple.
3. Simplify sdiv and srem code.
llvm-svn: 34680
2. Rewrite operator=(const APInt& RHS) to allow the RHS to be a different
bit width than the LHS. This makes it possible to use APInt as the key
of a DenseMap, as needed for the IntConstants map in Constants.cpp
3. Fix operator=(uint64_t) to clear unused bits in case the client assigns
a value that has more bits than the APInt allows.
4. Assert that bit widths are equal in operator==
5. Revise getHashValue() to put the bit width in the low order six bits.
This should help to make i1 0, i2 0, ... i64 0 all distinct in the
IntConstants DenseMap.
llvm-svn: 34646
2. Fix countTrailingZeros to use a faster algorithm.
3. Simplify sext() slightly by using isNegative().
4. Implement ashr using word-at-a-time logic instead of bit-at-a-time
5. Rename locals named isNegative so they don't clash with method name.
6. Fix fromString to compute negated value correctly.
llvm-svn: 34629
2. Move comments for methods to .h file, delete them in .cpp file.
3. All places that were doing manual clear of high order bits now call the
clearUnusedBits() method in order to not depend on undefined behavior
of the >> operator when the number of bits shifted equals the word size.
4. Reduced # of loc by using the new result of clearUnusedBits() method.
5. Simplified logic (decreased indentation) in a few places.
6. Added code comments to larger functions that needed them.
7. Added FIXME notes about weak implementations of things (e.g. bit-by-bit
shift right is sub-optimal).
llvm-svn: 34603
2. Clean up comments, style, coding standards, etc.
3. Simplify a constructor.
Extended testing revealed some additional bugs in shifting. I'll fix these
tomorrow.
llvm-svn: 34559
to be safe.
2. Make internal functions that return a carry/borrow return bool instead
of uint64_t because the carry/borrow can only be in range [0,1].
3. Assert that the pointers to KnuthDiv are all different so that the
result and operands can't overlap.
4. Add debug output to KnuthDiv function.
5. Fix a problem with KnuthDiv by separating the b's complement operation
from the subtraction borrow operation. This fixes a wide range of
division problems, but alas, not all of them.
llvm-svn: 34554
memory (as done in fromString).
2. Implement Knuth divide more closely to what is recommended in his book.
3. Fix computation of the remainder for Knuth Divide (bad shifting).
4. Remove some cruft from the file
llvm-svn: 34518
word size. This fixes all reads of uninitialized data (buffer over read)
and makes APInt.cpp memory clean, per valgrind. The only remaining
problem is division in a few cases.
llvm-svn: 34483
2. Change 0 initialization of union to larger component so all is zeroed.
3. Fix the borrow logic in subtraction so it works for > 128 bits.
4. Rewrite fromString to use a simpler but correct algorithm and also to
not set the bit width contrary to the user's request.
5. Optimize toString a bit by making it only do one Knuth divide per
iteration instead of two.
With these changes, all arithmetic passes (verified by pari/GP) up to
1024 bits except for certain division cases.
llvm-svn: 34463
1. Ensure pVal is set to 0 in each constructor.
2. Fix roundToDouble to make correct calculations and not read beyond the
end of allocated memory.
3. Implement Knuth's "classical algorithm" for division from scratch and
eliminate buffer overflows and uninitialized mememory reads. Document
it properly too.
4. Implement a wrapper function for KnuthDiv which handles the 64-bit to
32-bit conversion and back. It also implement short division for the
n == 1 case that Knuth's algorithm can't handle.
5. Simplify the logic of udiv and urem a little, make them exit early, and
have them use the "divide" wrapper function to perform the division
or remainder operation.
6. Move the toString function to the end of the file, closer to where
the division functions are located.
Note: division is still broken for some > 64 bit values, but at least it
doesn't crash any more.
llvm-svn: 34449
