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//
// Copyright 2016 The ANGLE Project Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
//
// Implementation of evaluating unary integer variable bug workaround.
// See header for more info.
#include "compiler/translator/tree_ops/d3d/RewriteUnaryMinusOperatorInt.h"
#include "compiler/translator/tree_util/IntermTraverse.h"
namespace sh
{
namespace
{
class Traverser : public TIntermTraverser
{
public:
[[nodiscard]] static bool Apply(TCompiler *compiler, TIntermNode *root);
private:
Traverser();
bool visitUnary(Visit visit, TIntermUnary *node) override;
void nextIteration();
bool mFound = false;
};
// static
bool Traverser::Apply(TCompiler *compiler, TIntermNode *root)
{
Traverser traverser;
do
{
traverser.nextIteration();
root->traverse(&traverser);
if (traverser.mFound)
{
if (!traverser.updateTree(compiler, root))
{
return false;
}
}
} while (traverser.mFound);
return true;
}
Traverser::Traverser() : TIntermTraverser(true, false, false) {}
void Traverser::nextIteration()
{
mFound = false;
}
bool Traverser::visitUnary(Visit visit, TIntermUnary *node)
{
if (mFound)
{
return false;
}
// Decide if the current unary operator is unary minus.
if (node->getOp() != EOpNegative)
{
return true;
}
// Decide if the current operand is an integer variable.
TIntermTyped *opr = node->getOperand();
if (!opr->getType().isScalarInt())
{
return true;
}
// Potential problem case detected, apply workaround: -(int) -> ~(int) + 1.
// ~(int)
TIntermUnary *bitwiseNot = new TIntermUnary(EOpBitwiseNot, opr, nullptr);
bitwiseNot->setLine(opr->getLine());
// Constant 1 (or 1u)
TConstantUnion *one = new TConstantUnion();
if (opr->getType().getBasicType() == EbtInt)
{
one->setIConst(1);
}
else
{
one->setUConst(1u);
}
TType *oneType = new TType(opr->getType());
oneType->setQualifier(EvqConst);
TIntermConstantUnion *oneNode = new TIntermConstantUnion(one, *oneType);
oneNode->setLine(opr->getLine());
// ~(int) + 1
TIntermBinary *add = new TIntermBinary(EOpAdd, bitwiseNot, oneNode);
add->setLine(opr->getLine());
queueReplacement(add, OriginalNode::IS_DROPPED);
mFound = true;
return false;
}
} // anonymous namespace
bool RewriteUnaryMinusOperatorInt(TCompiler *compiler, TIntermNode *root)
{
return Traverser::Apply(compiler, root);
}
} // namespace sh