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

[Stephen Tozer via llvm-commits]

================
@@ -173,8 +173,9 @@ Value *SSAUpdater::GetValueInMiddleOfBlock(BasicBlock *BB) {
 
   // Set the DebugLoc of the inserted PHI, if available.
   DebugLoc DL;
-  if (const Instruction *I = BB->getFirstNonPHI())
-      DL = I->getDebugLoc();
+  BasicBlock::iterator It = BB->getFirstNonPHIIt();
+  if (It != BB->end())
+    DL = It->getDebugLoc();
----------------
SLTozer wrote:

Possible alternative, YMMV:
```suggestion
  if (BasicBlock::iterator It = BB->getFirstNonPHIIt(); It != BB->end())
    DL = It->getDebugLoc();
```

https://github.com/llvm/llvm-project/pull/123737