Re: Loop unrolling
Tim Frink wrote:
Hi,
what are typical heuristics for loop unrolling, i.e. which constraints
must be satisfied to have a compiler perform unrolling on a particular
loop?
I assume that the loop must not exceed a particular size to avoid a
code size explosion. But are there any other heuristics?
They will be specific to the compiler and loops don't have to be
completely unrolled. For example a loop of 100 may be expanded to a
loop of 20 blocks of 5 repeats.
Some compilers provide a means for tuning loop unrolling as a
space/performance trade off.
--
Ian Collins.
.
Relevant Pages
- Re: Parallel programming with FORALL?
... pattern it knows how to deal with well. ... One oft-cited example is loop unrolling. ... Turns out that with today's compilers and architectures, loop unrolling ... can get in the way of the compiler doing things like ...
(comp.lang.fortran) - Re: Parallel programming with FORALL?
... pattern it knows how to deal with well. ... One oft-cited example is loop unrolling. ... Turns out that with today's compilers and architectures, loop unrolling ... can get in the way of the compiler doing things like ...
(comp.lang.fortran) - Re: Optimisation for tight loops...
... >> perl) can do loop unrolling and such. ... >> handle such things and optimize them out of a loop or unroll a loop. ... KT> the compiler *could* determine that the body of a loop doesn't do ... KT> (loop unrolling, common subexpression elimination, etc.). ...
(comp.lang.perl.misc) - Re: Optimisation for tight loops...
... KC> Does the Perl compiler/interpreter do any loop unrolling, ... KC> loop optimisations at all? ... the compiler *could* determine that the body of a loop doesn't do ...
(comp.lang.perl.misc) - Re: question
... SM Ryan wrote: ... > loop unrolling refers to replicating the body of a loop and reducing the total ... So it means that the loop unrooling is the compiler dependent? ...
(comp.lang.c) |
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