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, 7 insertions, 8 deletions

diff --git a/llvm/lib/Transforms/Scalar/Reassociate.cpp b/llvm/lib/Transforms/Scalar/Reassociate.cpp
index adfd5f9..dd8e7fb 100644
--- a/llvm/lib/Transforms/Scalar/Reassociate.cpp
+++ b/llvm/lib/Transforms/Scalar/Reassociate.cpp
@@ -956,14 +956,13 @@ static Value *NegateValue(Value *V, Instruction *BI) {
       } else if (auto *CPI = dyn_cast<CatchPadInst>(InstInput)) {
         InsertPt = CPI->getNormalDest()->begin();
       } else {
-        InsertPt = InstInput;
-        ++InsertPt;
+        InsertPt = ++InstInput->getIterator();
       }
       while (isa<PHINode>(InsertPt)) ++InsertPt;
     } else {
       InsertPt = TheNeg->getParent()->getParent()->getEntryBlock().begin();
     }
-    TheNeg->moveBefore(InsertPt);
+    TheNeg->moveBefore(&*InsertPt);
     if (TheNeg->getOpcode() == Instruction::Sub) {
       TheNeg->setHasNoUnsignedWrap(false);
       TheNeg->setHasNoSignedWrap(false);
@@ -1150,7 +1149,7 @@ Value *Reassociate::RemoveFactorFromExpression(Value *V, Value *Factor) {
     return nullptr;
   }
 
-  BasicBlock::iterator InsertPt = BO; ++InsertPt;
+  BasicBlock::iterator InsertPt = ++BO->getIterator();
 
   // If this was just a single multiply, remove the multiply and return the only
   // remaining operand.
@@ -1163,7 +1162,7 @@ Value *Reassociate::RemoveFactorFromExpression(Value *V, Value *Factor) {
   }
 
   if (NeedsNegate)
-    V = CreateNeg(V, "neg", InsertPt, BO);
+    V = CreateNeg(V, "neg", &*InsertPt, BO);
 
   return V;
 }
@@ -2234,10 +2233,10 @@ bool Reassociate::runOnFunction(Function &F) {
   for (Function::iterator BI = F.begin(), BE = F.end(); BI != BE; ++BI) {
     // Optimize every instruction in the basic block.
     for (BasicBlock::iterator II = BI->begin(), IE = BI->end(); II != IE; )
-      if (isInstructionTriviallyDead(II)) {
-        EraseInst(II++);
+      if (isInstructionTriviallyDead(&*II)) {
+        EraseInst(&*II++);
       } else {
-        OptimizeInst(II);
+        OptimizeInst(&*II);
         assert(II->getParent() == BI && "Moved to a different block!");
         ++II;
       }