[NFC][DebugInfo] Use iterator moveBefore at many call-sites (#123583)

As part of the "RemoveDIs" project, BasicBlock::iterator now carries a
debug-info bit that's needed when getFirstNonPHI and similar feed into
instruction insertion positions. Call-sites where that's necessary were
updated a year ago; but to ensure some type safety however, we'd like to
have all calls to moveBefore use iterators.

This patch adds a (guaranteed dereferenceable) iterator-taking
moveBefore, and changes a bunch of call-sites where it's obviously safe
to change to use it by just calling getIterator() on an instruction
pointer. A follow-up patch will contain less-obviously-safe changes.

We'll eventually deprecate and remove the instruction-pointer
insertBefore, but not before adding concise documentation of what
considerations are needed (very few).

1 files changed, 4 insertions, 4 deletions

diff --git a/llvm/lib/CodeGen/SelectOptimize.cpp b/llvm/lib/CodeGen/SelectOptimize.cpp
index bfc49dd..57488a9 100644
--- a/llvm/lib/CodeGen/SelectOptimize.cpp
+++ b/llvm/lib/CodeGen/SelectOptimize.cpp
@@ -512,7 +512,7 @@ static Value *getTrueOrFalseValue(
       CBO->setOperand(OtherIdx,
                       isTrue ? OptSelects[IV].first : OptSelects[IV].second);
   }
-  CBO->insertBefore(B->getTerminator());
+  CBO->insertBefore(B->getTerminator()->getIterator());
   return CBO;
 }
 
@@ -637,7 +637,7 @@ void SelectOptimizeImpl::convertProfitableSIGroups(SelectGroups &ProfSIGroups) {
     }
     auto InsertionPoint = EndBlock->getFirstInsertionPt();
     for (auto *DI : SinkInstrs)
-      DI->moveBeforePreserving(&*InsertionPoint);
+      DI->moveBeforePreserving(InsertionPoint);
 
     // Duplicate implementation for DbgRecords, the non-instruction debug-info
     // format. Helper lambda for moving DbgRecords to the end block.
@@ -675,7 +675,7 @@ void SelectOptimizeImpl::convertProfitableSIGroups(SelectGroups &ProfSIGroups) {
       TrueBranch = BranchInst::Create(EndBlock, TrueBlock);
       TrueBranch->setDebugLoc(LastSI.getI()->getDebugLoc());
       for (Instruction *TrueInst : TrueSlicesInterleaved)
-        TrueInst->moveBefore(TrueBranch);
+        TrueInst->moveBefore(TrueBranch->getIterator());
     }
     if (!FalseSlicesInterleaved.empty() || HasSelectLike(ASI, false)) {
       FalseBlock =
@@ -684,7 +684,7 @@ void SelectOptimizeImpl::convertProfitableSIGroups(SelectGroups &ProfSIGroups) {
       FalseBranch = BranchInst::Create(EndBlock, FalseBlock);
       FalseBranch->setDebugLoc(LastSI.getI()->getDebugLoc());
       for (Instruction *FalseInst : FalseSlicesInterleaved)
-        FalseInst->moveBefore(FalseBranch);
+        FalseInst->moveBefore(FalseBranch->getIterator());
     }
     // If there was nothing to sink, then arbitrarily choose the 'false' side
     // for a new input value to the PHI.