[llvm] [VPlan] Port invalid cost remarks to VPlan. (PR #99322)

[via llvm-commits]

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@@ -889,20 +890,18 @@ static void debugVectorizationMessage(const StringRef Prefix,
 /// \p PassName is the name of the pass (e.g. can be AlwaysPrint).  \p
 /// RemarkName is the identifier for the remark.  If \p I is passed it is an
 /// instruction that prevents vectorization.  Otherwise \p TheLoop is used for
-/// the location of the remark.  \return the remark object that can be
-/// streamed to.
-static OptimizationRemarkAnalysis createLVAnalysis(const char *PassName,
-    StringRef RemarkName, Loop *TheLoop, Instruction *I) {
-  Value *CodeRegion = TheLoop->getHeader();
-  DebugLoc DL = TheLoop->getStartLoc();
-
-  if (I) {
-    CodeRegion = I->getParent();
-    // If there is no debug location attached to the instruction, revert back to
-    // using the loop's.
-    if (I->getDebugLoc())
-      DL = I->getDebugLoc();
-  }
+/// the location of the remark. If \p DL is passed, use it as debug location for
+/// the remark. \return the remark object that can be streamed to.
+static OptimizationRemarkAnalysis
+createLVAnalysis(const char *PassName, StringRef RemarkName, Loop *TheLoop,
+                 Instruction *I, DebugLoc DL = {}) {
+  Value *CodeRegion = I ? I->getParent() : TheLoop->getHeader();
+  // If debug location is attached to the instruction, use it. Otherwise if DL
+  // was not provided, use the loop's.
+  if (I && I->getDebugLoc())
+    DL = I->getDebugLoc();
+  else if (!DL)
+    DL = TheLoop->getStartLoc();
----------------
ayalz wrote:

(post commit): slight discrepancy with documentation above, should this instead read
```
  // If debug location is provided, use it. Otherwise if debug location is attached to the instruction, use it. 
  // Otherwise use the start location of the loop.
  if (!DL)
    DL = (I && I->getDebugLoc()) ? I->getDebugLoc() : TheLoop->getStartLoc();
```

https://github.com/llvm/llvm-project/pull/99322