Scalar: Remove remaining ilist iterator implicit conversions

Remove remaining `ilist_iterator` implicit conversions from
LLVMScalarOpts.

This change exposed some scary behaviour in
lib/Transforms/Scalar/SCCP.cpp around line 1770.  This patch changes a
call from `Function::begin()` to `&Function::front()`, since the return
was immediately being passed into another function that takes a
`Function*`.  `Function::front()` started to assert, since the function
was empty.  Note that `Function::end()` does not point at a legal
`Function*` -- it points at an `ilist_half_node` -- so the other
function was getting garbage before.  (I added the missing check for
`Function::isDeclaration()`.)

Otherwise, no functionality change intended.

llvm-svn: 250211

1 files changed, 11 insertions, 9 deletions

diff --git a/llvm/lib/Transforms/Scalar/LoopUnswitch.cpp b/llvm/lib/Transforms/Scalar/LoopUnswitch.cpp
index 0f7ce7e..d55fad0 100644
--- a/llvm/lib/Transforms/Scalar/LoopUnswitch.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopUnswitch.cpp
@@ -782,7 +782,7 @@ void LoopUnswitch::UnswitchTrivialCondition(Loop *L, Value *Cond, Constant *Val,
   // without actually branching to it (the exit block should be dominated by the
   // loop header, not the preheader).
   assert(!L->contains(ExitBlock) && "Exit block is in the loop?");
-  BasicBlock *NewExit = SplitBlock(ExitBlock, ExitBlock->begin(), DT, LI);
+  BasicBlock *NewExit = SplitBlock(ExitBlock, &ExitBlock->front(), DT, LI);
 
   // Okay, now we have a position to branch from and a position to branch to,
   // insert the new conditional branch.
@@ -839,8 +839,8 @@ bool LoopUnswitch::TryTrivialLoopUnswitch(bool &Changed) {
     // Check if this loop will execute any side-effecting instructions (e.g.
     // stores, calls, volatile loads) in the part of the loop that the code
     // *would* execute. Check the header first.
-    for (BasicBlock::iterator I : *CurrentBB)
-      if (I->mayHaveSideEffects())
+    for (Instruction &I : *CurrentBB)
+      if (I.mayHaveSideEffects())
         return false;
 
     // FIXME: add check for constant foldable switch instructions.
@@ -1019,8 +1019,9 @@ void LoopUnswitch::UnswitchNontrivialCondition(Value *LIC, Constant *Val,
 
   // Splice the newly inserted blocks into the function right before the
   // original preheader.
-  F->getBasicBlockList().splice(NewPreheader, F->getBasicBlockList(),
-                                NewBlocks[0], F->end());
+  F->getBasicBlockList().splice(NewPreheader->getIterator(),
+                                F->getBasicBlockList(),
+                                NewBlocks[0]->getIterator(), F->end());
 
   // FIXME: We could register any cloned assumptions instead of clearing the
   // whole function's cache.
@@ -1062,7 +1063,7 @@ void LoopUnswitch::UnswitchNontrivialCondition(Value *LIC, Constant *Val,
 
     if (LandingPadInst *LPad = NewExit->getLandingPadInst()) {
       PHINode *PN = PHINode::Create(LPad->getType(), 0, "",
-                                    ExitSucc->getFirstInsertionPt());
+                                    &*ExitSucc->getFirstInsertionPt());
 
       for (pred_iterator I = pred_begin(ExitSucc), E = pred_end(ExitSucc);
            I != E; ++I) {
@@ -1078,7 +1079,8 @@ void LoopUnswitch::UnswitchNontrivialCondition(Value *LIC, Constant *Val,
   for (unsigned i = 0, e = NewBlocks.size(); i != e; ++i)
     for (BasicBlock::iterator I = NewBlocks[i]->begin(),
            E = NewBlocks[i]->end(); I != E; ++I)
-      RemapInstruction(I, VMap,RF_NoModuleLevelChanges|RF_IgnoreMissingEntries);
+      RemapInstruction(&*I, VMap,
+                       RF_NoModuleLevelChanges | RF_IgnoreMissingEntries);
 
   // Rewrite the original preheader to select between versions of the loop.
   BranchInst *OldBR = cast<BranchInst>(loopPreheader->getTerminator());
@@ -1322,8 +1324,8 @@ void LoopUnswitch::SimplifyCode(std::vector<Instruction*> &Worklist, Loop *L) {
         Succ->replaceAllUsesWith(Pred);
 
         // Move all of the successor contents from Succ to Pred.
-        Pred->getInstList().splice(BI, Succ->getInstList(), Succ->begin(),
-                                   Succ->end());
+        Pred->getInstList().splice(BI->getIterator(), Succ->getInstList(),
+                                   Succ->begin(), Succ->end());
         LPM->deleteSimpleAnalysisValue(BI, L);
         BI->eraseFromParent();
         RemoveFromWorklist(BI, Worklist);