[NFC][RemoveDIs] Bulk update utilities to insert with iterators

As part of the RemoveDIs project we need LLVM to insert instructions using
iterators wherever possible, so that the iterators can carry a bit of
debug-info. This commit implements some of that by updating the contents of
llvm/lib/Transforms/Utils to always use iterator-versions of instruction
constructors.

There are two general flavours of update:
 * Almost all call-sites just call getIterator on an instruction
 * Several make use of an existing iterator (scenarios where the code is
   actually significant for debug-info)
The underlying logic is that any call to getFirstInsertionPt or similar
APIs that identify the start of a block need to have that iterator passed
directly to the insertion function, without being converted to a bare
Instruction pointer along the way.

I've also switched DemotePHIToStack to take an optional iterator: it needs
to take an iterator, and having a no-insert-location behaviour appears to
be important. The constructors for ICmpInst and FCmpInst have been updated
too. They're the only instructions that take block _references_ rather than
pointers for certain calls, and a future patch is going to make use of
default-null block insertion locations.

All of this should be NFC.

1 files changed, 2 insertions, 2 deletions

diff --git a/llvm/lib/Transforms/Utils/ScalarEvolutionExpander.cpp b/llvm/lib/Transforms/Utils/ScalarEvolutionExpander.cpp
index 0f67cc3..3a3bcde 100644
--- a/llvm/lib/Transforms/Utils/ScalarEvolutionExpander.cpp
+++ b/llvm/lib/Transforms/Utils/ScalarEvolutionExpander.cpp
@@ -1267,7 +1267,7 @@ Value *SCEVExpander::visitAddRecExpr(const SCEVAddRecExpr *S) {
         // corresponding to the back-edge.
         Instruction *Add = BinaryOperator::CreateAdd(CanonicalIV, One,
                                                      "indvar.next",
-                                                     HP->getTerminator());
+                                                     HP->getTerminator()->getIterator());
         Add->setDebugLoc(HP->getTerminator()->getDebugLoc());
         rememberInstruction(Add);
         CanonicalIV->addIncoming(Add, HP);
@@ -2232,7 +2232,7 @@ Value *SCEVExpander::fixupLCSSAFormFor(Value *V) {
   if (!PreserveLCSSA || !DefI)
     return V;
 
-  Instruction *InsertPt = &*Builder.GetInsertPoint();
+  BasicBlock::iterator InsertPt = Builder.GetInsertPoint();
   Loop *DefLoop = SE.LI.getLoopFor(DefI->getParent());
   Loop *UseLoop = SE.LI.getLoopFor(InsertPt->getParent());
   if (!DefLoop || UseLoop == DefLoop || DefLoop->contains(UseLoop))