Commit Graph

15 Commits

Author SHA1 Message Date
dan sinclair
eda2cfbe12
Cleanup includes. (#1795)
This Cl cleans up the include paths to be relative to the top level
directory. Various include-what-you-use fixes have been added.
2018-08-03 15:06:09 -04:00
dan sinclair
58a6876cee
Rewrite include guards (#1793)
This CL rewrites the include guards to make PRESUBMIT.py include guard
check happy.
2018-08-03 08:05:33 -04:00
dan sinclair
c7da51a085
Cleanup extraneous namespace qualifies in source/opt. (#1716)
This CL follows up on the opt namespacing CLs by removing the
unnecessary opt:: and opt::analysis:: namespace prefixes.
2018-07-12 15:14:43 -04:00
dan sinclair
e6b953361d
Move the ir namespace to opt. (#1680)
This CL moves the files in opt/ to consistenly be under the opt::
namespace. This frees up the ir:: namespace so it can be used to make a
shared ir represenation.
2018-07-09 11:32:29 -04:00
dan sinclair
3dad1cda11
Change libspirv to spvtools namespace (#1678)
This CL changes all of the libspirv namespace code to spvtools to match
the rest of the code base.
2018-07-07 09:38:00 -04:00
Alan Baker
c3f34d8bf3 Fixes #1300. Adding checks for bad CCP transitions and unsettled values
* Now track propagation status and assert on bad statuses
 * Added helper methods to access instruction propagation status
* Modified the phi meet operator to properly reflect the paper it is
based on
* Modified SSA edge addition so that all edge are added, but only on
state changes
* Fixed a bug in instruction simulation where interesting conditional
branches would not mark the interesting edge as executed
 * Added a test to catch this bug
* Added an ostream operator for SSAPropagator::PropStatus
2018-02-18 19:41:34 -05:00
Alan Baker
1b46f7ecad Fixes in CCP for #1228
* Forces traversal of phis if the def has changed to varying
* Mark a phi as varying if all incoming values are varying
* added a test to catch the bug
2018-01-29 15:12:05 -05:00
Diego Novillo
e5560d64de Fix constant propagation of induction variables.
This fixes https://github.com/KhronosGroup/SPIRV-Tools/issues/1143.
When an instruction transitions from constant to bottom (varying) in the
lattice, we were telling the propagator that the instruction was
varying, but never updating the actual value in the values table.

This led to incorrect value substitutions at the end of propagation.

The patch also re-enables CCP in -O and -Os.
2018-01-08 15:34:35 -05:00
Diego Novillo
716718a5e9 Fix infinite simulation cycles in SSA propagator.
This fixes https://github.com/KhronosGroup/SPIRV-Tools/issues/1159.  I
had missed a nuance in the original algorithm.  When simulating Phi
instructions, the SSA edges out of a Phi instruction should never be
added to the list of edges to simulate.

Phi instructions can be in SSA def-use cycles with other Phi
instructions.  This was causing the propagator to fall into an infinite
loop when the same def-use edge kept being added to the queue.

The original algorithm in the paper specifically separates the visit of
a Phi instruction vs the visit of a regular instruction.  This fix makes
the implementation match the original algorithm.
2018-01-05 10:29:39 -05:00
Diego Novillo
5b52626eaa Address review comments from https://github.com/KhronosGroup/SPIRV-Tools/pull/985. 2018-01-04 13:20:49 -05:00
Diego Novillo
1acce99255 Fix https://github.com/KhronosGroup/SPIRV-Tools/issues/1130
This addresses review feedback for the CCP implementation (which fixes
https://github.com/KhronosGroup/SPIRV-Tools/issues/889).

This adds more protection around the folding of instructions that would
not be supported by the folder.
2017-12-22 13:33:17 -05:00
Diego Novillo
4ba9dcc8a0 Implement SSA CCP (SSA Conditional Constant Propagation).
This implements the conditional constant propagation pass proposed in

Constant propagation with conditional branches,
Wegman and Zadeck, ACM TOPLAS 13(2):181-210.

The main logic resides in CCPPass::VisitInstruction.  Instruction that
may produce a constant value are evaluated with the constant folder. If
they produce a new constant, the instruction is considered interesting.
Otherwise, it's considered varying (for unfoldable instructions) or
just not interesting (when not enough operands have a constant value).

The other main piece of logic is in CCPPass::VisitBranch.  This
evaluates the selector of the branch.  When it's found to be a known
value, it computes the destination basic block and sets it.  This tells
the propagator which branches to follow.

The patch required extensions to the constant manager as well. Instead
of hashing the Constant pointers, this patch changes the constant pool
to hash the contents of the Constant.  This allows the lookups to be
done using the actual values of the Constant, preventing duplicate
definitions.
2017-12-21 14:29:45 -05:00
Diego Novillo
e9ecc0cbfd Remove cfg_ field from SSAPropagator class - NFC.
When I moved the CFG into IRContext
(https://github.com/KhronosGroup/SPIRV-Tools/pull/1019), I forgot to
update SSAPropagator to stop requiring one.

Fixed with this patch.
2017-12-04 15:28:21 -05:00
Diego Novillo
8cfa0c40e0 Fix #1034 - Give Edge::operator<() weak ordering semantics.
This should fix #1034.  It changes the predicate on operator< to use
label IDs from each block and compares them as std:pair to define a weak
ordering for std::set.
2017-11-29 17:29:17 -05:00
Diego Novillo
74327845aa Generic value propagation engine.
This class implements a generic value propagation algorithm based on the
conditional constant propagation algorithm proposed in

     Constant propagation with conditional branches,
     Wegman and Zadeck, ACM TOPLAS 13(2):181-210.

The implementation is based on

     A Propagation Engine for GCC
     Diego Novillo, GCC Summit 2005
     http://ols.fedoraproject.org/GCC/Reprints-2005/novillo-Reprint.pdf

The purpose of this implementation is to act as a common framework for any
transformation that needs to propagate values from statements producing new
values to statements using those values.
2017-11-27 23:32:06 -05:00