[C++11] Add range based accessors for the Use-Def chain of a Value.
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
diff --git a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
index 600c963..0cab81b 100644
--- a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
@@ -641,10 +641,9 @@
// uses into the PHI.
if (!PN->hasOneUse()) {
// Walk the use list for the instruction, comparing them to I.
- for (Value::use_iterator UI = PN->use_begin(), E = PN->use_end();
- UI != E; ++UI) {
- Instruction *User = cast<Instruction>(*UI);
- if (User != &I && !I.isIdenticalTo(User))
+ for (User *U : PN->users()) {
+ Instruction *UI = cast<Instruction>(U);
+ if (UI != &I && !I.isIdenticalTo(UI))
return 0;
}
// Otherwise, we can replace *all* users with the new PHI we form.
@@ -759,8 +758,7 @@
}
}
- for (Value::use_iterator UI = PN->use_begin(), E = PN->use_end();
- UI != E; ) {
+ for (auto UI = PN->user_begin(), E = PN->user_end(); UI != E;) {
Instruction *User = cast<Instruction>(*UI++);
if (User == &I) continue;
ReplaceInstUsesWith(*User, NewPN);
@@ -1080,7 +1078,7 @@
// Move up one level in the expression.
assert(Ancestor->hasOneUse() && "Drilled down when more than one use!");
- Ancestor = Ancestor->use_back();
+ Ancestor = Ancestor->user_back();
} while (1);
}
@@ -1425,9 +1423,8 @@
do {
Instruction *PI = Worklist.pop_back_val();
- for (Value::use_iterator UI = PI->use_begin(), UE = PI->use_end(); UI != UE;
- ++UI) {
- Instruction *I = cast<Instruction>(*UI);
+ for (User *U : PI->users()) {
+ Instruction *I = cast<Instruction>(U);
switch (I->getOpcode()) {
default:
// Give up the moment we see something we can't handle.
@@ -2404,12 +2401,12 @@
// See if we can trivially sink this instruction to a successor basic block.
if (I->hasOneUse()) {
BasicBlock *BB = I->getParent();
- Instruction *UserInst = cast<Instruction>(I->use_back());
+ Instruction *UserInst = cast<Instruction>(*I->user_begin());
BasicBlock *UserParent;
// Get the block the use occurs in.
if (PHINode *PN = dyn_cast<PHINode>(UserInst))
- UserParent = PN->getIncomingBlock(I->use_begin().getUse());
+ UserParent = PN->getIncomingBlock(*I->use_begin());
else
UserParent = UserInst->getParent();