Commit Graph

14 Commits

Author SHA1 Message Date
Benjamin Kramer af0ed953c5 Avoid turning a floating point division with a constant power of two into a denormal multiplication.
Some platforms may treat denormals as zero, on other platforms multiplication
with a subnormal is slower than dividing by a normal.

llvm-svn: 128555
2011-03-30 17:02:54 +00:00
Benjamin Kramer 03fd672609 Add APFloat::getExactInverse.
The idea is, that if an ieee 754 float is divided by a power of two, we can
turn the division into a cheaper multiplication. This function sees if we can
get an exact multiplicative inverse for a divisor and returns it if possible.

This is the hard part of PR9587.

I tested many inputs against llvm-gcc's frotend implementation of this
optimization and didn't find any difference. However, floating point is the
land of weird edge cases, so any review would be appreciated.

llvm-svn: 128545
2011-03-30 15:42:27 +00:00
Jeffrey Yasskin b5cd01335b Fix death tests in -Asserts builds.
llvm-svn: 98701
2010-03-17 01:18:45 +00:00
John McCall dcb9a7ad3d Teach APFloat how to create both QNaNs and SNaNs and with arbitrary-width
payloads.  APFloat's internal folding routines always make QNaNs now,
instead of sometimes making QNaNs and sometimes SNaNs depending on the
type.

llvm-svn: 97364
2010-02-28 02:51:25 +00:00
John McCall b42cc681ba Make APFloat's string-parsing routines a bit safer against very large exponents.
llvm-svn: 97278
2010-02-26 22:20:41 +00:00
John McCall df951bddb8 Make APInt::countLeadingZerosSlowCase() treat the contents of padding bits
as undefined.  Fixes an assertion in APFloat::toString noticed by Dale.

llvm-svn: 95196
2010-02-03 03:42:44 +00:00
John McCall dd5044ac55 Implement support for converting to string at "natural precision", and fix some
major bugs in long-precision conversion.

llvm-svn: 92150
2009-12-24 23:18:09 +00:00
John McCall 29b5c284ae Add accessors for the largest-magnitude, smallest-magnitude, and
smallest-normalized-magnitude values in a given FP semantics.
Provide an APFloat-to-string conversion which I am quite ready to admit could
be much more efficient.

llvm-svn: 92126
2009-12-24 08:56:26 +00:00
Daniel Dunbar bc52e4fe73 Add test for PR4873, which works for me.
llvm-svn: 80965
2009-09-03 22:57:02 +00:00
Erick Tryzelaar da666c801c Add support for including '+' in APFloat strings, more asserts,
and many new unit tests.

llvm-svn: 79574
2009-08-20 23:30:43 +00:00
Daniel Dunbar bf5998edfb Fix two APFloat bugs in converting hexadecimal constants.
llvm-svn: 79540
2009-08-20 17:12:33 +00:00
Erick Tryzelaar 927191f179 Wrap unit test death tests in GTEST_HAS_DEATH_TEST
llvm-svn: 79218
2009-08-17 00:55:33 +00:00
Erick Tryzelaar bc0d74944e Change APFloatTest from using ASSERTs to EXPECTs
llvm-svn: 79216
2009-08-17 00:14:11 +00:00
Erick Tryzelaar 19f63b2e4d Modify APFloat to take a StringRef instead of a c string.
This also adds unit tests to APFloat that mainly tests the
string handling of APFloat, but not much else of it's api.

llvm-svn: 79210
2009-08-16 23:36:19 +00:00