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Revampt ReplaceAllUsesWith to be more efficient and easier to use. 

llvm-svn: 23087
This commit is contained in:
Chris Lattner 2005-08-26 18:36:28 +00:00
parent fa0be24960
commit 373f048a79
1 changed files with 54 additions and 6 deletions
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60
llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
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@ -2008,8 +2008,53 @@ void SelectionDAG::SelectNodeTo(SDNode *N, unsigned TargetOpc,
/// ReplaceAllUsesWith - Modify anything using 'From' to use 'To' instead.
/// This can cause recursive merging of nodes in the DAG.
///
void SelectionDAG::ReplaceAllUsesWith(SDNode *From, SDNode *To) {
/// This version assumes From/To have a single result value.
///
void SelectionDAG::ReplaceAllUsesWith(SDOperand FromN, SDOperand ToN) {
SDNode *From = FromN.Val, *To = ToN.Val;
assert(From->getNumValues() == 1 && To->getNumValues() == 1 &&
"Cannot replace with this method!");
assert(From != To && "Cannot replace uses of with self");
assert(From->getValueType(0) == To->getValueType(0) &&
"Replacing with different values");
while (!From->use_empty()) {
// Process users until they are all gone.
SDNode *U = *From->use_begin();
// This node is about to morph, remove its old self from the CSE maps.
RemoveNodeFromCSEMaps(U);
for (unsigned i = 0, e = U->getNumOperands(); i != e; ++i)
if (U->getOperand(i).Val == From) {
From->removeUser(U);
U->Operands[i].Val = To;
To->addUser(U);
}
// Now that we have modified U, add it back to the CSE maps. If it already
// exists there, recursively merge the results together.
if (SDNode *Existing = AddNonLeafNodeToCSEMaps(U))
ReplaceAllUsesWith(U, Existing);
// U is now dead.
}
}
/// ReplaceAllUsesWith - Modify anything using 'From' to use 'To' instead.
/// This can cause recursive merging of nodes in the DAG.
///
/// This version assumes From/To have matching types and numbers of result
/// values.
///
void SelectionDAG::ReplaceAllUsesWith(SDNode *From, SDNode *To) {
assert(From != To && "Cannot replace uses of with self");
assert(From->getNumValues() == To->getNumValues() &&
"Cannot use this version of ReplaceAllUsesWith!");
if (From->getNumValues() == 1) { // If possible, use the faster version.
ReplaceAllUsesWith(SDOperand(From, 0), SDOperand(To, 0));
return;
}
while (!From->use_empty()) {
// Process users until they are all gone.
SDNode *U = *From->use_begin();
@ -2019,8 +2064,6 @@ void SelectionDAG::ReplaceAllUsesWith(SDNode *From, SDNode *To) {
for (unsigned i = 0, e = U->getNumOperands(); i != e; ++i)
if (U->getOperand(i).Val == From) {
assert(U->getOperand(i).getValueType() ==
To->getValueType(U->getOperand(i).ResNo));
From->removeUser(U);
U->Operands[i].Val = To;
To->addUser(U);
@ -2030,17 +2073,22 @@ void SelectionDAG::ReplaceAllUsesWith(SDNode *From, SDNode *To) {
// exists there, recursively merge the results together.
if (SDNode *Existing = AddNonLeafNodeToCSEMaps(U))
ReplaceAllUsesWith(U, Existing);
// U is now dead.
// U is now dead.
}
}
/// ReplaceAllUsesWith - Modify anything using 'From' to use 'To' instead.
/// This can cause recursive merging of nodes in the DAG.
///
/// This version can replace From with any result values. To must match the
/// number and types of values returned by From.
void SelectionDAG::ReplaceAllUsesWith(SDNode *From,
const std::vector<SDOperand> &To) {
assert(From->getNumValues() == To.size() &&
"Incorrect number of values to replace with!");
if (To.size() == 1 && To[0].ResNo == 0) {
if (To.size() == 1) {
// Degenerate case handled above.
ReplaceAllUsesWith(From, To[0].Val);
ReplaceAllUsesWith(SDOperand(From, 0), To[0]);
return;
}