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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
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28
llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
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@@ -88,9 +88,8 @@ public:
/// isOnlyUsedInZeroEqualityComparison - Return true if it only matters that the
/// value is equal or not-equal to zero.
static bool isOnlyUsedInZeroEqualityComparison(Value *V) {
for (Value::use_iterator UI = V->use_begin(), E = V->use_end();
UI != E; ++UI) {
if (ICmpInst *IC = dyn_cast<ICmpInst>(*UI))
for (User *U : V->users()) {
if (ICmpInst *IC = dyn_cast<ICmpInst>(U))
if (IC->isEquality())
if (Constant *C = dyn_cast<Constant>(IC->getOperand(1)))
if (C->isNullValue())
@@ -104,9 +103,8 @@ static bool isOnlyUsedInZeroEqualityComparison(Value *V) {
/// isOnlyUsedInEqualityComparison - Return true if it is only used in equality
/// comparisons with With.
static bool isOnlyUsedInEqualityComparison(Value *V, Value *With) {
for (Value::use_iterator UI = V->use_begin(), E = V->use_end();
UI != E; ++UI) {
if (ICmpInst *IC = dyn_cast<ICmpInst>(*UI))
for (User *U : V->users()) {
if (ICmpInst *IC = dyn_cast<ICmpInst>(U))
if (IC->isEquality() && IC->getOperand(1) == With)
continue;
// Unknown instruction.
@@ -936,8 +934,7 @@ struct StrStrOpt : public LibCallOptimization {
StrLen, B, DL, TLI);
if (!StrNCmp)
return 0;
for (Value::use_iterator UI = CI->use_begin(), UE = CI->use_end();
UI != UE; ) {
for (auto UI = CI->user_begin(), UE = CI->user_end(); UI != UE;) {
ICmpInst *Old = cast<ICmpInst>(*UI++);
Value *Cmp = B.CreateICmp(Old->getPredicate(), StrNCmp,
ConstantInt::getNullValue(StrNCmp->getType()),
@@ -1110,9 +1107,8 @@ struct UnaryDoubleFPOpt : public LibCallOptimization {
if (CheckRetType) {
// Check if all the uses for function like 'sin' are converted to float.
for (Value::use_iterator UseI = CI->use_begin(); UseI != CI->use_end();
++UseI) {
FPTruncInst *Cast = dyn_cast<FPTruncInst>(*UseI);
for (User *U : CI->users()) {
FPTruncInst *Cast = dyn_cast<FPTruncInst>(U);
if (Cast == 0 || !Cast->getType()->isFloatTy())
return 0;
}
@@ -1147,9 +1143,8 @@ struct BinaryDoubleFPOpt : public LibCallOptimization {
if (CheckRetType) {
// Check if all the uses for function like 'fmin/fmax' are converted to
// float.
for (Value::use_iterator UseI = CI->use_begin(); UseI != CI->use_end();
++UseI) {
FPTruncInst *Cast = dyn_cast<FPTruncInst>(*UseI);
for (User *U : CI->users()) {
FPTruncInst *Cast = dyn_cast<FPTruncInst>(U);
if (Cast == 0 || !Cast->getType()->isFloatTy())
return 0;
}
@@ -1361,9 +1356,8 @@ struct SinCosPiOpt : public LibCallOptimization {
// Look for all compatible sinpi, cospi and sincospi calls with the same
// argument. If there are enough (in some sense) we can make the
// substitution.
for (Value::use_iterator UI = Arg->use_begin(), UE = Arg->use_end();
UI != UE; ++UI)
classifyArgUse(*UI, CI->getParent(), IsFloat, SinCalls, CosCalls,
for (User *U : Arg->users())
classifyArgUse(U, CI->getParent(), IsFloat, SinCalls, CosCalls,
SinCosCalls);
// It's only worthwhile if both sinpi and cospi are actually used.