summaryrefslogtreecommitdiff
path: root/Source/ThirdParty/ANGLE/src/compiler/translator/RemovePow.cpp
diff options
context:
space:
mode:
authorLorry Tar Creator <lorry-tar-importer@lorry>2017-06-27 06:07:23 +0000
committerLorry Tar Creator <lorry-tar-importer@lorry>2017-06-27 06:07:23 +0000
commit1bf1084f2b10c3b47fd1a588d85d21ed0eb41d0c (patch)
tree46dcd36c86e7fbc6e5df36deb463b33e9967a6f7 /Source/ThirdParty/ANGLE/src/compiler/translator/RemovePow.cpp
parent32761a6cee1d0dee366b885b7b9c777e67885688 (diff)
downloadWebKitGtk-tarball-master.tar.gz
Diffstat (limited to 'Source/ThirdParty/ANGLE/src/compiler/translator/RemovePow.cpp')
-rw-r--r--Source/ThirdParty/ANGLE/src/compiler/translator/RemovePow.cpp94
1 files changed, 94 insertions, 0 deletions
diff --git a/Source/ThirdParty/ANGLE/src/compiler/translator/RemovePow.cpp b/Source/ThirdParty/ANGLE/src/compiler/translator/RemovePow.cpp
new file mode 100644
index 000000000..4b0fe6948
--- /dev/null
+++ b/Source/ThirdParty/ANGLE/src/compiler/translator/RemovePow.cpp
@@ -0,0 +1,94 @@
+//
+// Copyright (c) 2002-2015 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.
+//
+// RemovePow is an AST traverser to convert pow(x, y) built-in calls where y is a
+// constant to exp2(y * log2(x)). This works around an issue in NVIDIA 311 series
+// OpenGL drivers.
+//
+
+#include "compiler/translator/RemovePow.h"
+
+#include "compiler/translator/InfoSink.h"
+#include "compiler/translator/IntermNode.h"
+
+namespace
+{
+
+bool IsProblematicPow(TIntermTyped *node)
+{
+ TIntermAggregate *agg = node->getAsAggregate();
+ if (agg != nullptr && agg->getOp() == EOpPow)
+ {
+ ASSERT(agg->getSequence()->size() == 2);
+ return agg->getSequence()->at(1)->getAsConstantUnion() != nullptr;
+ }
+ return false;
+}
+
+// Traverser that converts all pow operations simultaneously.
+class RemovePowTraverser : public TIntermTraverser
+{
+ public:
+ RemovePowTraverser();
+
+ bool visitAggregate(Visit visit, TIntermAggregate *node) override;
+
+ void nextIteration() { mNeedAnotherIteration = false; }
+ bool needAnotherIteration() const { return mNeedAnotherIteration; }
+
+ protected:
+ bool mNeedAnotherIteration;
+};
+
+RemovePowTraverser::RemovePowTraverser()
+ : TIntermTraverser(true, false, false),
+ mNeedAnotherIteration(false)
+{
+}
+
+bool RemovePowTraverser::visitAggregate(Visit visit, TIntermAggregate *node)
+{
+ if (IsProblematicPow(node))
+ {
+ TIntermTyped *x = node->getSequence()->at(0)->getAsTyped();
+ TIntermTyped *y = node->getSequence()->at(1)->getAsTyped();
+
+ TIntermUnary *log = new TIntermUnary(EOpLog2, x);
+ log->setLine(node->getLine());
+
+ TOperator op = TIntermBinary::GetMulOpBasedOnOperands(y->getType(), log->getType());
+ TIntermBinary *mul = new TIntermBinary(op, y, log);
+ mul->setLine(node->getLine());
+
+ TIntermUnary *exp = new TIntermUnary(EOpExp2, mul);
+ exp->setLine(node->getLine());
+
+ queueReplacement(node, exp, OriginalNode::IS_DROPPED);
+
+ // If the x parameter also needs to be replaced, we need to do that in another traversal,
+ // since it's parent node will change in a way that's not handled correctly by updateTree().
+ if (IsProblematicPow(x))
+ {
+ mNeedAnotherIteration = true;
+ return false;
+ }
+ }
+ return true;
+}
+
+} // namespace
+
+void RemovePow(TIntermNode *root)
+{
+ RemovePowTraverser traverser;
+ // Iterate as necessary, and reset the traverser between iterations.
+ do
+ {
+ traverser.nextIteration();
+ root->traverse(&traverser);
+ traverser.updateTree();
+ }
+ while (traverser.needAnotherIteration());
+}