SCoP invariant parameters with the different start value would deter parameter
sharing. For example, when compiling the following C code:
void foo(float *input) {
for (long j = 0; j < 8; j++) {
// SCoP begin
for (long i = 0; i < 8; i++) {
float x = input[j * 64 + i + 1];
input[j * 64 + i] = x * x;
}
}
}
Polly would creat two parameters for these memory accesses:
p_0: {0,+,256}
p_2: {4,+,256}
[j * 64 + i + 1] => MemRef_input[o0] : 4o0 = p_1 + 4i0
[j * 64 + i] => MemRef_input[o0] : 4o0 = p_0 + 4i0
These parameters only differ from start value. To enable parameter sharing,
we split the start value from SCEVAddRecExpr, so they would share a single
parameter that always has zero start value:
p0: {0,+,256}<%for.cond1.preheader>
[j * 64 + i + 1] => MemRef_input[o0] : 4o0 = 4 + p_1 + 4i0
[j * 64 + i] => MemRef_input[o0] : 4o0 = p_0 + 4i0
Such translation can make the polly-dependence much faster.
Contributed-by: Star Tan <tanmx_star@yeah.net>
llvm-svn: 187728
isl recently introduced isl_val as an abstract interface to represent arbitrary
precision numbers. This interface superseeds the old isl_int interface. In
contrast to the old interface which implemented arbitrary precision arithmetic
using macros that forward to the gmp library, the new library hides the math
library implementation in isl. This allows us to switch the math library used by
isl without affecting users such as Polly.
llvm-svn: 184529
After this commit, polly is clang-format clean. This can be tested with
'ninja polly-check-format'. Updates to clang-format may change this, but the
differences will hopefully be both small and general improvements to the
formatting.
We currently have some not very nice formatting for a couple of items, DEBUG()
stmts for example. I believe the benefit of being clang-format clean outweights
the not perfect layout of this code.
llvm-svn: 177796
We now detect scops without a canonical induction variable and can generate a
polyhedral representation for them. There was no modification necessary to
code generate these scops.
llvm-svn: 177643
We fix the following formatting problems found by clang-format:
- 80 cols violations
- Obvious problems with missing or too many spaces
- multiple new lines in a row
clang-format suggests many more changes, most of them falling in the following
two categories:
1) clang-format does not at all format a piece of code nicely
2) The style that clang-format suggests does not match the style used in
Polly/LLVM
I consider differences caused by reason 1) bugs, which should be fixed by
improving clang-format. Differences due to 2) need to be investigated closer
to understand the cause of the difference and the solution that should be taken.
llvm-svn: 171241
This ensures that the isl sets/maps we operate on have the same parameter
dimensions. Operations on objects with different parameter dimensions are not
allow and trigger assertions.
llvm-svn: 163618
This includes:
- The isl_id of the domain of the scattering must be copied from the original
domain
- Remove outdated references to a 'FinalRead' statement
- Print of the Pocc output, if -debug is provided.
- Add line breaks to some error messages.
Reported and Debugged by: Dustin Feld <d3.feld@gmail.com>
llvm-svn: 162901
Store a pointer to each ScopStmt in the isl_id associated with the space of its
domain. This will later allow us to recover the statement during code
generation with isl.
llvm-svn: 157607
Derive the maximal and minimal values of a parameter from the type it has. Add
this information to the scop context. This information is needed, to derive
optimal types during code generation.
llvm-svn: 157245
There is no need for special code to handle SCEVUnknowns. SCEVUnkowns are always
parameters and will be handled by the generic parameter handling code in
visit().
llvm-svn: 157243
The FinalRead statement represented a virtual read that is executed after the
SCoP. It was used when we verified the correctness of a schedule by checking if
it yields the same FLOW dependences as the original code. This is only works, if
we have a final read that reads all memory at the end of the SCoP.
We now switched to just checking if a schedule does not introduce negative
dependences and also consider WAW WAR dependences. This restricts the schedules
a little bit more, but we do not have any optimizer that would calculate a more
complex schedule. Hence, for now final reads are obsolete.
llvm-svn: 152319
In case we can not analyze an access function, we do not discard the SCoP, but
assume conservatively that all memory accesses that can be derived from our base
pointer may be accessed.
Patch provided by: Marcello Maggioni <hayarms@gmail.com>
llvm-svn: 146972
Parameters can be complex SCEV expressions, but they can also be single scalar
values. If a parameters is such a simple scalar value and the value is named,
use this name to name the isl parameter dimensions.
llvm-svn: 144641
address is part of the access function. Also remove unused special cases that
were necessery when the base address was still contained in the access function
llvm-svn: 144280
Tobias Grosser