[NFC][DebugInfo] Use iterator-flavour getFirstNonPHI at many call-sites (#123737)

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 getFirstNonPHI use the iterator-returning version.

This patch changes a bunch of call-sites calling getFirstNonPHI to use
getFirstNonPHIIt, which returns an iterator. All these call sites are
where it's obviously safe to fetch the iterator then dereference it. A
follow-up patch will contain less-obviously-safe changes.

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

---------

Co-authored-by: Stephen Tozer <Melamoto@gmail.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/llvm/lib/CodeGen/SelectOptimize.cpp b/llvm/lib/CodeGen/SelectOptimize.cpp
index 57488a9..b7600a3 100644
--- a/llvm/lib/CodeGen/SelectOptimize.cpp
+++ b/llvm/lib/CodeGen/SelectOptimize.cpp
@@ -1217,7 +1217,7 @@ bool SelectOptimizeImpl::checkLoopHeuristics(const Loop *L,
     return true;
 
   OptimizationRemarkMissed ORmissL(DEBUG_TYPE, "SelectOpti",
-                                   L->getHeader()->getFirstNonPHI());
+                                   &*L->getHeader()->getFirstNonPHIIt());
 
   if (LoopCost[0].NonPredCost > LoopCost[0].PredCost ||
       LoopCost[1].NonPredCost >= LoopCost[1].PredCost) {