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[C++11] Add range based accessors for the Use-Def chain of a Value.

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This requires a number of steps.
1) Move value_use_iterator into the Value class as an implementation
   detail
2) Change it to actually be a *Use* iterator rather than a *User*
   iterator.
3) Add an adaptor which is a User iterator that always looks through the
   Use to the User.
4) Wrap these in Value::use_iterator and Value::user_iterator typedefs.
5) Add the range adaptors as Value::uses() and Value::users().
6) Update *all* of the callers to correctly distinguish between whether
   they wanted a use_iterator (and to explicitly dig out the User when
   needed), or a user_iterator which makes the Use itself totally
   opaque.

Because #6 requires churning essentially everything that walked the
Use-Def chains, I went ahead and added all of the range adaptors and
switched them to range-based loops where appropriate. Also because the
renaming requires at least churning every line of code, it didn't make
any sense to split these up into multiple commits -- all of which would
touch all of the same lies of code.

The result is still not quite optimal. The Value::use_iterator is a nice
regular iterator, but Value::user_iterator is an iterator over User*s
rather than over the User objects themselves. As a consequence, it fits
a bit awkwardly into the range-based world and it has the weird
extra-dereferencing 'operator->' that so many of our iterators have.
I think this could be fixed by providing something which transforms
a range of T&s into a range of T*s, but that *can* be separated into
another patch, and it isn't yet 100% clear whether this is the right
move.

However, this change gets us most of the benefit and cleans up
a substantial amount of code around Use and User. =]

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@203364 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chandler Carruth
2014-03-09 03:16:01 +00:00
parent b033b03c23
commit 36b699f2b1
100 changed files with 920 additions and 1075 deletions
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68
lib/Transforms/Vectorize/SLPVectorizer.cpp
View File

@@ -561,19 +561,18 @@ void BoUpSLP::buildTree(ArrayRef<Value *> Roots, ValueSet *Rdx) {
if (Entry->NeedToGather)
continue;
for (Value::use_iterator User = Scalar->use_begin(),
UE = Scalar->use_end(); User != UE; ++User) {
DEBUG(dbgs() << "SLP: Checking user:" << **User << ".\n");
for (User *U : Scalar->users()) {
DEBUG(dbgs() << "SLP: Checking user:" << *U << ".\n");
// Skip in-tree scalars that become vectors.
if (ScalarToTreeEntry.count(*User)) {
if (ScalarToTreeEntry.count(U)) {
DEBUG(dbgs() << "SLP: \tInternal user will be removed:" <<
**User << ".\n");
int Idx = ScalarToTreeEntry[*User]; (void) Idx;
*U << ".\n");
int Idx = ScalarToTreeEntry[U]; (void) Idx;
assert(!VectorizableTree[Idx].NeedToGather && "Bad state");
continue;
}
Instruction *UserInst = dyn_cast<Instruction>(*User);
Instruction *UserInst = dyn_cast<Instruction>(U);
if (!UserInst)
continue;
@@ -581,9 +580,9 @@ void BoUpSLP::buildTree(ArrayRef<Value *> Roots, ValueSet *Rdx) {
if (Rdx && std::find(Rdx->begin(), Rdx->end(), UserInst) != Rdx->end())
continue;
DEBUG(dbgs() << "SLP: Need to extract:" << **User << " from lane " <<
DEBUG(dbgs() << "SLP: Need to extract:" << *U << " from lane " <<
Lane << " from " << *Scalar << ".\n");
ExternalUses.push_back(ExternalUser(Scalar, *User, Lane));
ExternalUses.push_back(ExternalUser(Scalar, U, Lane));
}
}
}
@@ -670,57 +669,56 @@ void BoUpSLP::buildTree_rec(ArrayRef<Value *> VL, unsigned Depth) {
for (unsigned i = 0, e = VL.size(); i != e; ++i) {
Instruction *Scalar = cast<Instruction>(VL[i]);
DEBUG(dbgs() << "SLP: Checking users of " << *Scalar << ". \n");
for (Value::use_iterator U = Scalar->use_begin(), UE = Scalar->use_end();
U != UE; ++U) {
DEBUG(dbgs() << "SLP: \tUser " << **U << ". \n");
Instruction *User = dyn_cast<Instruction>(*U);
if (!User) {
for (User *U : Scalar->users()) {
DEBUG(dbgs() << "SLP: \tUser " << *U << ". \n");
Instruction *UI = dyn_cast<Instruction>(U);
if (!UI) {
DEBUG(dbgs() << "SLP: Gathering due unknown user. \n");
newTreeEntry(VL, false);
return;
}
// We don't care if the user is in a different basic block.
BasicBlock *UserBlock = User->getParent();
BasicBlock *UserBlock = UI->getParent();
if (UserBlock != BB) {
DEBUG(dbgs() << "SLP: User from a different basic block "
<< *User << ". \n");
<< *UI << ". \n");
continue;
}
// If this is a PHINode within this basic block then we can place the
// extract wherever we want.
if (isa<PHINode>(*User)) {
DEBUG(dbgs() << "SLP: \tWe can schedule PHIs:" << *User << ". \n");
if (isa<PHINode>(*UI)) {
DEBUG(dbgs() << "SLP: \tWe can schedule PHIs:" << *UI << ". \n");
continue;
}
// Check if this is a safe in-tree user.
if (ScalarToTreeEntry.count(User)) {
int Idx = ScalarToTreeEntry[User];
if (ScalarToTreeEntry.count(UI)) {
int Idx = ScalarToTreeEntry[UI];
int VecLocation = VectorizableTree[Idx].LastScalarIndex;
if (VecLocation <= MyLastIndex) {
DEBUG(dbgs() << "SLP: Gathering due to unschedulable vector. \n");
newTreeEntry(VL, false);
return;
}
DEBUG(dbgs() << "SLP: In-tree user (" << *User << ") at #" <<
DEBUG(dbgs() << "SLP: In-tree user (" << *UI << ") at #" <<
VecLocation << " vector value (" << *Scalar << ") at #"
<< MyLastIndex << ".\n");
continue;
}
// This user is part of the reduction.
if (RdxOps && RdxOps->count(User))
if (RdxOps && RdxOps->count(UI))
continue;
// Make sure that we can schedule this unknown user.
BlockNumbering &BN = BlocksNumbers[BB];
int UserIndex = BN.getIndex(User);
int UserIndex = BN.getIndex(UI);
if (UserIndex < MyLastIndex) {
DEBUG(dbgs() << "SLP: Can't schedule extractelement for "
<< *User << ". \n");
<< *UI << ". \n");
newTreeEntry(VL, false);
return;
}
@@ -739,11 +737,10 @@ void BoUpSLP::buildTree_rec(ArrayRef<Value *> VL, unsigned Depth) {
// Check that instructions in this bundle don't reference other instructions.
// The runtime of this check is O(N * N-1 * uses(N)) and a typical N is 4.
for (unsigned i = 0, e = VL.size(); i < e; ++i) {
for (Value::use_iterator U = VL[i]->use_begin(), UE = VL[i]->use_end();
U != UE; ++U) {
for (User *U : VL[i]->users()) {
for (unsigned j = 0; j < e; ++j) {
if (i != j && *U == VL[j]) {
DEBUG(dbgs() << "SLP: Intra-bundle dependencies!" << **U << ". \n");
if (i != j && U == VL[j]) {
DEBUG(dbgs() << "SLP: Intra-bundle dependencies!" << *U << ". \n");
newTreeEntry(VL, false);
return;
}
@@ -1595,8 +1592,8 @@ Value *BoUpSLP::vectorizeTree() {
// Skip users that we already RAUW. This happens when one instruction
// has multiple uses of the same value.
if (std::find(Scalar->use_begin(), Scalar->use_end(), User) ==
Scalar->use_end())
if (std::find(Scalar->user_begin(), Scalar->user_end(), User) ==
Scalar->user_end())
continue;
assert(ScalarToTreeEntry.count(Scalar) && "Invalid scalar");
@@ -1657,13 +1654,12 @@ Value *BoUpSLP::vectorizeTree() {
Type *Ty = Scalar->getType();
if (!Ty->isVoidTy()) {
for (Value::use_iterator User = Scalar->use_begin(),
UE = Scalar->use_end(); User != UE; ++User) {
DEBUG(dbgs() << "SLP: \tvalidating user:" << **User << ".\n");
for (User *U : Scalar->users()) {
DEBUG(dbgs() << "SLP: \tvalidating user:" << *U << ".\n");
assert((ScalarToTreeEntry.count(*User) ||
assert((ScalarToTreeEntry.count(U) ||
// It is legal to replace the reduction users by undef.
(RdxOps && RdxOps->count(*User))) &&
(RdxOps && RdxOps->count(U))) &&
"Replacing out-of-tree value with undef");
}
Value *Undef = UndefValue::get(Ty);
@@ -2466,7 +2462,7 @@ static bool findBuildVector(InsertElementInst *IE,
if (IE->use_empty())
return false;
InsertElementInst *NextUse = dyn_cast<InsertElementInst>(IE->use_back());
InsertElementInst *NextUse = dyn_cast<InsertElementInst>(IE->user_back());
if (!NextUse)
return true;