本文整理汇总了C++中MControlInstruction::valueNumber方法的典型用法代码示例。如果您正苦于以下问题：C++ MControlInstruction::valueNumber方法的具体用法？C++ MControlInstruction::valueNumber怎么用？C++ MControlInstruction::valueNumber使用的例子？那么, 这里精选的方法代码示例或许可以为您提供帮助。您也可以进一步了解该方法所在类MControlInstruction的用法示例。
在下文中一共展示了MControlInstruction::valueNumber方法的1个代码示例，这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞，您的评价将有助于系统推荐出更棒的C++代码示例。
示例1: IonSpew
bool
ValueNumberer::computeValueNumbers()
{
// At the end of this function, we will have the value numbering stored in
// each instruction.
//
// We also need an "optimistic" value number, for temporary use, which is
// stored in a hashtable.
//
// For the instruction x := y op z, we map (op, VN[y], VN[z]) to a value
// number, say v. If it is not in the map, we use the instruction id.
//
// If the instruction in question's value number is not already
// v, we break the congruence and set it to v. We repeat until saturation.
// This will take at worst O(d) time, where d is the loop connectedness
// of the SSA def/use graph.
//
// The algorithm is the simple RPO-based algorithm from
// "SCC-Based Value Numbering" by Cooper and Simpson.
//
// If we are performing a pessimistic pass, then we assume that every
// definition is in its own congruence class, since we know nothing about
// values that enter Phi nodes through back edges. We then make one pass
// through the graph, ignoring back edges. This yields less congruences on
// any graph with back-edges, but is much faster to perform.
IonSpew(IonSpew_GVN, "Numbering instructions");
if (!values.init())
return false;
// Stick a VN object onto every mdefinition
for (ReversePostorderIterator block(graph_.rpoBegin()); block != graph_.rpoEnd(); block++) {
for (MDefinitionIterator iter(*block); iter; iter++)
iter->setValueNumberData(new ValueNumberData);
MControlInstruction *jump = block->lastIns();
jump->setValueNumberData(new ValueNumberData);
}
// Assign unique value numbers if pessimistic.
// It might be productive to do this in the MDefinition constructor or
// possibly in a previous pass, if it seems reasonable.
if (pessimisticPass_) {
for (ReversePostorderIterator block(graph_.rpoBegin()); block != graph_.rpoEnd(); block++) {
for (MDefinitionIterator iter(*block); iter; iter++)
iter->setValueNumber(iter->id());
}
} else {
// For each root block, add all of its instructions to the worklist.
markBlock(*(graph_.begin()));
if (graph_.osrBlock())
markBlock(graph_.osrBlock());
}
while (count_ > 0) {
#ifdef DEBUG
if (!pessimisticPass_) {
size_t debugCount = 0;
IonSpew(IonSpew_GVN, "The following instructions require processing:");
for (ReversePostorderIterator block(graph_.rpoBegin()); block != graph_.rpoEnd(); block++) {
for (MDefinitionIterator iter(*block); iter; iter++) {
if (iter->isInWorklist()) {
IonSpew(IonSpew_GVN, "\t%d", iter->id());
debugCount++;
}
}
if (block->lastIns()->isInWorklist()) {
IonSpew(IonSpew_GVN, "\t%d", block->lastIns()->id());
debugCount++;
}
}
if (!debugCount)
IonSpew(IonSpew_GVN, "\tNone");
JS_ASSERT(debugCount == count_);
}
#endif
for (ReversePostorderIterator block(graph_.rpoBegin()); block != graph_.rpoEnd(); block++) {
for (MDefinitionIterator iter(*block); iter; ) {
if (!isMarked(*iter)) {
iter++;
continue;
}
JS_ASSERT_IF(!pessimisticPass_, count_ > 0);
unmarkDefinition(*iter);
MDefinition *ins = simplify(*iter, false);
if (ins != *iter) {
iter = block->discardDefAt(iter);
continue;
}
uint32 value = lookupValue(ins);
if (!value)
return false; // Hashtable insertion failed
if (ins->valueNumber() != value) {
IonSpew(IonSpew_GVN,
//.........这里部分代码省略.........