Commit Graph

5 Commits

Author SHA1 Message Date
Steven Perron
9ba0879ddf Improve Vector DCE
Track live scalars in VDCE as if they were single element vectors.

Handle the extended instructions for GLSL in VDCE.

Handle composite construct instructions in VDCE.
2018-04-30 11:55:50 -04:00
Steven Perron
a00a0a09ae Revert "Improvements to vector dce."
This reverts commit 2813722993.

A regression was found.  Undoing the change until it is fixed.
2018-04-27 10:33:19 -04:00
Steven Perron
2813722993 Improvements to vector dce.
Track live scalars in VDCE as if they were single element vectors.

Handle the extended instructions for GLSL in VDCE.

Handle composite construct instructions in VDCE.

Fixes #1511.
2018-04-26 11:07:48 -04:00
Neil Roberts
57a2441791 hex_float: Use max_digits10 for the float precision
CPPreference.com has this description of digits10:

“The value of std::numeric_limits<T>::digits10 is the number of
 base-10 digits that can be represented by the type T without change,
 that is, any number with this many significant decimal digits can be
 converted to a value of type T and back to decimal form, without
 change due to rounding or overflow.”

This means that any number with this many digits can be represented
accurately in the corresponding type. A change in any digit in a
number after that may or may not cause it a different bitwise
representation. Therefore this isn’t necessarily enough precision to
accurately represent the value in text. Instead we need max_digits10
which has the following description:

“The value of std::numeric_limits<T>::max_digits10 is the number of
 base-10 digits that are necessary to uniquely represent all distinct
 values of the type T, such as necessary for
 serialization/deserialization to text.”

The patch includes a test case in hex_float_test which tries to do a
round-robin conversion of a number that requires more than 6 decimal
places to be accurately represented. This would fail without the
patch.

Sadly this also breaks a bunch of other tests. Some of the tests in
hex_float_test use ldexp and then compare it with a value which is not
the same as the one returned by ldexp but instead is the value rounded
to 6 decimals. Others use values that are not evenly representable as
a binary floating fraction but then happened to generate the same
value when rounded to 6 decimals. Where the actual value didn’t seem
to matter these have been changed with different values that can be
represented as a binary fraction.
2018-04-03 12:53:10 -04:00
GregF
f28b106173 InsertExtractElim: Split out DeadInsertElim as separate pass 2018-01-30 08:52:14 -05:00