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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. =]

llvm-svn: 203364
This commit is contained in:
Chandler Carruth
2014-03-09 03:16:01 +00:00
parent c980afc578
commit cdf4788401
100 changed files with 920 additions and 1075 deletions
Download Patch File Download Diff File Expand all files Collapse all files

78
llvm/lib/CodeGen/CodeGenPrepare.cpp
View File

@@ -336,16 +336,15 @@ bool CodeGenPrepare::CanMergeBlocks(const BasicBlock *BB,
// don't mess around with them.
BasicBlock::const_iterator BBI = BB->begin();
while (const PHINode *PN = dyn_cast<PHINode>(BBI++)) {
for (Value::const_use_iterator UI = PN->use_begin(), E = PN->use_end();
UI != E; ++UI) {
const Instruction *User = cast<Instruction>(*UI);
if (User->getParent() != DestBB || !isa<PHINode>(User))
for (const User *U : PN->users()) {
const Instruction *UI = cast<Instruction>(U);
if (UI->getParent() != DestBB || !isa<PHINode>(UI))
return false;
// If User is inside DestBB block and it is a PHINode then check
// incoming value. If incoming value is not from BB then this is
// a complex condition (e.g. preheaders) we want to avoid here.
if (User->getParent() == DestBB) {
if (const PHINode *UPN = dyn_cast<PHINode>(User))
if (UI->getParent() == DestBB) {
if (const PHINode *UPN = dyn_cast<PHINode>(UI))
for (unsigned I = 0, E = UPN->getNumIncomingValues(); I != E; ++I) {
Instruction *Insn = dyn_cast<Instruction>(UPN->getIncomingValue(I));
if (Insn && Insn->getParent() == BB &&
@@ -474,7 +473,7 @@ static bool SinkCast(CastInst *CI) {
DenseMap<BasicBlock*, CastInst*> InsertedCasts;
bool MadeChange = false;
for (Value::use_iterator UI = CI->use_begin(), E = CI->use_end();
for (Value::user_iterator UI = CI->user_begin(), E = CI->user_end();
UI != E; ) {
Use &TheUse = UI.getUse();
Instruction *User = cast<Instruction>(*UI);
@@ -483,7 +482,7 @@ static bool SinkCast(CastInst *CI) {
// appropriate predecessor block.
BasicBlock *UserBB = User->getParent();
if (PHINode *PN = dyn_cast<PHINode>(User)) {
UserBB = PN->getIncomingBlock(UI);
UserBB = PN->getIncomingBlock(TheUse);
}
// Preincrement use iterator so we don't invalidate it.
@@ -567,7 +566,7 @@ static bool OptimizeCmpExpression(CmpInst *CI) {
DenseMap<BasicBlock*, CmpInst*> InsertedCmps;
bool MadeChange = false;
for (Value::use_iterator UI = CI->use_begin(), E = CI->use_end();
for (Value::user_iterator UI = CI->user_begin(), E = CI->user_end();
UI != E; ) {
Use &TheUse = UI.getUse();
Instruction *User = cast<Instruction>(*UI);
@@ -1143,11 +1142,9 @@ class TypePromotionTransaction {
DEBUG(dbgs() << "Do: UsersReplacer: " << *Inst << " with " << *New
<< "\n");
// Record the original uses.
for (Value::use_iterator UseIt = Inst->use_begin(),
EndIt = Inst->use_end();
UseIt != EndIt; ++UseIt) {
Instruction *Use = cast<Instruction>(*UseIt);
OriginalUses.push_back(InstructionAndIdx(Use, UseIt.getOperandNo()));
for (Use &U : Inst->uses()) {
Instruction *UserI = cast<Instruction>(U.getUser());
OriginalUses.push_back(InstructionAndIdx(UserI, U.getOperandNo()));
}
// Now, we can replace the uses.
Inst->replaceAllUsesWith(New);
@@ -2115,23 +2112,22 @@ static bool FindAllMemoryUses(Instruction *I,
return true;
// Loop over all the uses, recursively processing them.
for (Value::use_iterator UI = I->use_begin(), E = I->use_end();
UI != E; ++UI) {
User *U = *UI;
for (Use &U : I->uses()) {
Instruction *UserI = cast<Instruction>(U.getUser());
if (LoadInst *LI = dyn_cast<LoadInst>(U)) {
MemoryUses.push_back(std::make_pair(LI, UI.getOperandNo()));
if (LoadInst *LI = dyn_cast<LoadInst>(UserI)) {
MemoryUses.push_back(std::make_pair(LI, U.getOperandNo()));
continue;
}
if (StoreInst *SI = dyn_cast<StoreInst>(U)) {
unsigned opNo = UI.getOperandNo();
if (StoreInst *SI = dyn_cast<StoreInst>(UserI)) {
unsigned opNo = U.getOperandNo();
if (opNo == 0) return true; // Storing addr, not into addr.
MemoryUses.push_back(std::make_pair(SI, opNo));
continue;
}
if (CallInst *CI = dyn_cast<CallInst>(U)) {
if (CallInst *CI = dyn_cast<CallInst>(UserI)) {
InlineAsm *IA = dyn_cast<InlineAsm>(CI->getCalledValue());
if (!IA) return true;
@@ -2141,8 +2137,7 @@ static bool FindAllMemoryUses(Instruction *I,
continue;
}
if (FindAllMemoryUses(cast<Instruction>(U), MemoryUses, ConsideredInsts,
TLI))
if (FindAllMemoryUses(UserI, MemoryUses, ConsideredInsts, TLI))
return true;
}
@@ -2603,12 +2598,11 @@ bool CodeGenPrepare::OptimizeExtUses(Instruction *I) {
return false;
bool DefIsLiveOut = false;
for (Value::use_iterator UI = I->use_begin(), E = I->use_end();
UI != E; ++UI) {
Instruction *User = cast<Instruction>(*UI);
for (User *U : I->users()) {
Instruction *UI = cast<Instruction>(U);
// Figure out which BB this ext is used in.
BasicBlock *UserBB = User->getParent();
BasicBlock *UserBB = UI->getParent();
if (UserBB == DefBB) continue;
DefIsLiveOut = true;
break;
@@ -2617,14 +2611,13 @@ bool CodeGenPrepare::OptimizeExtUses(Instruction *I) {
return false;
// Make sure none of the uses are PHI nodes.
for (Value::use_iterator UI = Src->use_begin(), E = Src->use_end();
UI != E; ++UI) {
Instruction *User = cast<Instruction>(*UI);
BasicBlock *UserBB = User->getParent();
for (User *U : Src->users()) {
Instruction *UI = cast<Instruction>(U);
BasicBlock *UserBB = UI->getParent();
if (UserBB == DefBB) continue;
// Be conservative. We don't want this xform to end up introducing
// reloads just before load / store instructions.
if (isa<PHINode>(User) || isa<LoadInst>(User) || isa<StoreInst>(User))
if (isa<PHINode>(UI) || isa<LoadInst>(UI) || isa<StoreInst>(UI))
return false;
}
@@ -2632,10 +2625,8 @@ bool CodeGenPrepare::OptimizeExtUses(Instruction *I) {
DenseMap<BasicBlock*, Instruction*> InsertedTruncs;
bool MadeChange = false;
for (Value::use_iterator UI = Src->use_begin(), E = Src->use_end();
UI != E; ++UI) {
Use &TheUse = UI.getUse();
Instruction *User = cast<Instruction>(*UI);
for (Use &U : Src->uses()) {
Instruction *User = cast<Instruction>(U.getUser());
// Figure out which BB this ext is used in.
BasicBlock *UserBB = User->getParent();
@@ -2651,7 +2642,7 @@ bool CodeGenPrepare::OptimizeExtUses(Instruction *I) {
}
// Replace a use of the {s|z}ext source with a use of the result.
TheUse = InsertedTrunc;
U = InsertedTrunc;
++NumExtUses;
MadeChange = true;
}
@@ -2779,16 +2770,15 @@ bool CodeGenPrepare::OptimizeShuffleVectorInst(ShuffleVectorInst *SVI) {
DenseMap<BasicBlock*, Instruction*> InsertedShuffles;
bool MadeChange = false;
for (Value::use_iterator UI = SVI->use_begin(), E = SVI->use_end();
UI != E; ++UI) {
Instruction *User = cast<Instruction>(*UI);
for (User *U : SVI->users()) {
Instruction *UI = cast<Instruction>(U);
// Figure out which BB this ext is used in.
BasicBlock *UserBB = User->getParent();
BasicBlock *UserBB = UI->getParent();
if (UserBB == DefBB) continue;
// For now only apply this when the splat is used by a shift instruction.
if (!User->isShift()) continue;
if (!UI->isShift()) continue;
// Everything checks out, sink the shuffle if the user's block doesn't
// already have a copy.
@@ -2801,7 +2791,7 @@ bool CodeGenPrepare::OptimizeShuffleVectorInst(ShuffleVectorInst *SVI) {
SVI->getOperand(2), "", InsertPt);
}
User->replaceUsesOfWith(SVI, InsertedShuffle);
UI->replaceUsesOfWith(SVI, InsertedShuffle);
MadeChange = true;
}