From cdf4788401afff02e12279fc1fded94d6180639c Mon Sep 17 00:00:00 2001 From: Chandler Carruth Date: Sun, 9 Mar 2014 03:16:01 +0000 Subject: [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 --- llvm/lib/Transforms/Scalar/LoopUnswitch.cpp | 25 +++++++++++-------------- 1 file changed, 11 insertions(+), 14 deletions(-) (limited to 'llvm/lib/Transforms/Scalar/LoopUnswitch.cpp') diff --git a/llvm/lib/Transforms/Scalar/LoopUnswitch.cpp b/llvm/lib/Transforms/Scalar/LoopUnswitch.cpp index 61de996cffc..5954f4af51f 100644 --- a/llvm/lib/Transforms/Scalar/LoopUnswitch.cpp +++ b/llvm/lib/Transforms/Scalar/LoopUnswitch.cpp @@ -939,9 +939,8 @@ static void ReplaceUsesOfWith(Instruction *I, Value *V, Worklist.push_back(Use); // Add users to the worklist which may be simplified now. - for (Value::use_iterator UI = I->use_begin(), E = I->use_end(); - UI != E; ++UI) - Worklist.push_back(cast(*UI)); + for (User *U : I->users()) + Worklist.push_back(cast(U)); LPM->deleteSimpleAnalysisValue(I, L); RemoveFromWorklist(I, Worklist); I->replaceAllUsesWith(V); @@ -991,12 +990,11 @@ void LoopUnswitch::RewriteLoopBodyWithConditionConstant(Loop *L, Value *LIC, Replacement = ConstantInt::get(Type::getInt1Ty(Val->getContext()), !cast(Val)->getZExtValue()); - for (Value::use_iterator UI = LIC->use_begin(), E = LIC->use_end(); - UI != E; ++UI) { - Instruction *U = dyn_cast(*UI); - if (!U || !L->contains(U)) + for (User *U : LIC->users()) { + Instruction *UI = dyn_cast(U); + if (!UI || !L->contains(UI)) continue; - Worklist.push_back(U); + Worklist.push_back(UI); } for (std::vector::iterator UI = Worklist.begin(), @@ -1010,19 +1008,18 @@ void LoopUnswitch::RewriteLoopBodyWithConditionConstant(Loop *L, Value *LIC, // Otherwise, we don't know the precise value of LIC, but we do know that it // is certainly NOT "Val". As such, simplify any uses in the loop that we // can. This case occurs when we unswitch switch statements. - for (Value::use_iterator UI = LIC->use_begin(), E = LIC->use_end(); - UI != E; ++UI) { - Instruction *U = dyn_cast(*UI); - if (!U || !L->contains(U)) + for (User *U : LIC->users()) { + Instruction *UI = dyn_cast(U); + if (!UI || !L->contains(UI)) continue; - Worklist.push_back(U); + Worklist.push_back(UI); // TODO: We could do other simplifications, for example, turning // 'icmp eq LIC, Val' -> false. // If we know that LIC is not Val, use this info to simplify code. - SwitchInst *SI = dyn_cast(U); + SwitchInst *SI = dyn_cast(UI); if (SI == 0 || !isa(Val)) continue; SwitchInst::CaseIt DeadCase = SI->findCaseValue(cast(Val)); -- cgit v1.2.3