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// Header for ImplicitConditionalBarriers pass.
//
// Copyright (c) 2013 Pekka Jääskeläinen / TUT
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
#ifndef POCL_IMPLICIT_CONDITIONAL_BARRIERS_H
#define POCL_IMPLICIT_CONDITIONAL_BARRIERS_H
#include "config.h"
#include <llvm/IR/Function.h>
#include <llvm/IR/PassManager.h>
#include <llvm/Pass.h>
#include <llvm/Passes/PassBuilder.h>
/**
* Adds implicit barriers to branches to minimize the adverse effects from
* "peeling" to the symmetry of the work-item loops created for conditional
* barrier cases.
*
* In essence, the pass converts the following cases:
.[P].
| |
a b
[B]
to
.[P].
[B] [B]
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a b
[B]
Legend: [P] is a BB with the predicate.
[B] is a barrier.
a and b are regular basic blocks.
We can inject the barrier legally due to the barrier semantics:
'a' or 'b' are entered by all or none of the work-items. Thus,
the additional barrier is legal there as well.
This creates a nice static trip count work-item parallel loop around 'a' and
'b' instead of needing to peel the first iteration that creates
an asymmetric loop with dynamic iteration count.
*/
namespace pocl {
class ImplicitConditionalBarriers
: public llvm::PassInfoMixin<ImplicitConditionalBarriers> {
public:
static void registerWithPB(llvm::PassBuilder &B);
llvm::PreservedAnalyses run(llvm::Function &F,
llvm::FunctionAnalysisManager &AM);
static bool isRequired() { return true; }
};
}
#endif
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