Commit Graph

12 Commits

Author SHA1 Message Date
Jeff Bolz
60fac96c6b Enable precompiled headers for spirv-tools(-shared) and some unit tests (#2026) 2018-11-06 09:26:23 -05:00
David Neto
700ebd3442 Make fewer test executables
Try to reduce the amount of disk space used by especially by debug builds,
which may be contributing to AppVeyor failures.

Collapses tests in categories:
- validator
- loop optimizations
- dominator analysis
- linker

Contributes to #1615
2018-06-12 09:48:42 -04:00
Toomas Remmelg
1dc2458060 Add a loop fusion pass.
This pass will look for adjacent loops that are compatible and legal to
be fused.

Loops are compatible if:

- they both have one induction variable
- they have the same upper and lower bounds
    - same initial value
    - same condition
- they have the same update step
- they are adjacent
- there are no break/continue in either of them

Fusion is legal if:

- fused loops do not have any dependencies with dependence distance
  greater than 0 that did not exist in the original loops.
- there are no function calls in the loops (could have side-effects)
- there are no barriers in the loops

It will fuse all such loops as long as the number of registers used for
the fused loop stays under the threshold defined by
max_registers_per_loop.
2018-05-01 15:40:37 -04:00
Stephen McGroarty
9a5dd6fe88 Support loop fission.
Adds support for spliting loops whose register pressure exceeds a user
provided level. This pass will split a loop into two or more loops given
that the loop is a top level loop and that spliting the loop is legal.
Control flow is left intact for dead code elimination to remove.

This pass is enabled with the --loop-fission flag to spirv-opt.
2018-05-01 15:15:10 -04:00
Victor Lomuller
10e5d7cf13 Add a loop peeling pass.
For each loop in a function, the pass walks the loops from inner to outer most loop
and tries to peel loop for which a certain amount of iteration can be done before or after the loop.

To limit code growth, peeling will not happen if the growth in code size goes above a configurable threshold.
2018-04-11 15:41:29 +01:00
Alexander Johnston
61b50b3bfa ZIV and SIV loop dependence analysis.
Provides functionality to perform ZIV and SIV dependency analysis tests
between a load and store within the same loop.

Dependency tests rely on scalar analysis to prove and disprove dependencies
with regard to the loop being analysed.

Based on the 1990 paper Practical Dependence Testing by Goff, Kennedy, Tseng

Adds support for marking loops in the loop nest as IRRELEVANT.
Loops are marked IRRELEVANT if the analysed instructions contain
no induction variables for the loops, i.e. the loops induction
variable is not relevent to the dependence of the store and load.
2018-04-11 09:32:42 -04:00
Victor Lomuller
bdf421cf40 Add loop peeling utility
The loop peeler util takes a loop as input and create a new one before.
The iterator of the duplicated loop then set to accommodate the number
of iteration required for the peeling.

The loop peeling pass that decided to do the peeling and profitability
analysis is left for a follow-up PR.
2018-03-20 10:21:10 -04:00
Victor Lomuller
3497a94460 Add loop unswitch pass.
It moves all conditional branching and switch whose conditions are loop
invariant and uniform. Before performing the loop unswitch we check that
the loop does not contain any instruction that would prevent it
(barriers, group instructions etc.).
2018-02-27 08:52:46 -05:00
Stephen McGroarty
dd8400e150 Initial support for loop unrolling.
This patch adds initial support for loop unrolling in the form of a
series of utility classes which perform the unrolling. The pass can
be run with the command spirv-opt --loop-unroll. This will unroll
loops within the module which have the unroll hint set. The unroller
imposes a number of requirements on the loops it can unroll. These are
documented in the comments for the LoopUtils::CanPerformUnroll method in
loop_utils.h. Some of the restrictions will be lifted in future patches.
2018-02-14 15:44:38 -05:00
Alexander Johnston
84ccd0b9ae Loop invariant code motion initial implementation 2018-02-08 22:55:47 -05:00
Victor Lomuller
50e85c865c Add LoopUtils class to gather some loop transformation support.
This patch adds LoopUtils class to handle some loop related transformations. For now it has 2 transformations that simplifies other transformations such as loop unroll or unswitch:
 - Dedicate exit blocks: this ensure that all exit basic block
   (out-of-loop basic blocks that have a predecessor in the loop)
   have all their predecessors in the loop;
 - Loop Closed SSA (LCSSA): this ensure that all definitions in a loop are used inside the loop
   or in a phi instruction in an exit basic block.

It also adds the following capabilities:
 - Loop::IsLCSSA to test if the loop is in a LCSSA form
 - Loop::GetOrCreatePreHeaderBlock that can build a loop preheader if required;
 - New methods to allow on the fly updates of the loop descriptors.
 - New methods to allow on the fly updates of the CFG analysis.
 - Instruction::SetOperand to allow expression of the index relative to Instruction::NumOperands (to be compatible with the index returned by DefUseManager::ForEachUse)
2018-02-01 15:35:09 -05:00
Victor Lomuller
e8ad02f3dd Add loop descriptors and some required dominator tree extensions.
Add post-order tree iterator.

Add DominatorTreeNode extensions:
 - Add begin/end methods to do pre-order and post-order tree traversal from a given DominatorTreeNode

Add DominatorTree extensions:
  - Add begin/end methods to do pre-order and post-order tree traversal
  - Tree traversal ignore by default the pseudo entry block
  - Retrieve a DominatorTreeNode from a basic block

Add loop descriptor:
  - Add a LoopDescriptor class to register all loops in a given function.
  - Add a Loop class to describe a loop:
    - Loop parent
    - Nested loops
    - Loop depth
    - Loop header, merge, continue and preheader
    - Basic blocks that belong to the loop

Correct a bug that forced dominator tree to be constantly rebuilt.
2018-01-08 09:31:13 -05:00