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, 4 insertions, 5 deletions

diff --git a/llvm/lib/Transforms/Scalar/SimplifyCFGPass.cpp b/llvm/lib/Transforms/Scalar/SimplifyCFGPass.cpp
index c766fae56df..63c8836bf38 100644
--- a/llvm/lib/Transforms/Scalar/SimplifyCFGPass.cpp
+++ b/llvm/lib/Transforms/Scalar/SimplifyCFGPass.cpp
@@ -68,15 +68,14 @@ static bool mergeEmptyReturnBlocks(Function &F) {
     // single PHI node that is the operand to the return.
     if (Ret != &BB.front()) {
       // Check for something else in the block.
-      BasicBlock::iterator I = Ret;
+      BasicBlock::iterator I(Ret);
       --I;
       // Skip over debug info.
       while (isa<DbgInfoIntrinsic>(I) && I != BB.begin())
         --I;
       if (!isa<DbgInfoIntrinsic>(I) &&
-          (!isa<PHINode>(I) || I != BB.begin() ||
-           Ret->getNumOperands() == 0 ||
-           Ret->getOperand(0) != I))
+          (!isa<PHINode>(I) || I != BB.begin() || Ret->getNumOperands() == 0 ||
+           Ret->getOperand(0) != &*I))
         continue;
     }
 
@@ -137,7 +136,7 @@ static bool iterativelySimplifyCFG(Function &F, const TargetTransformInfo &TTI,
 
     // Loop over all of the basic blocks and remove them if they are unneeded.
     for (Function::iterator BBIt = F.begin(); BBIt != F.end(); ) {
-      if (SimplifyCFG(BBIt++, TTI, BonusInstThreshold, AC)) {
+      if (SimplifyCFG(&*BBIt++, TTI, BonusInstThreshold, AC)) {
         LocalChange = true;
         ++NumSimpl;
       }