[clang] [Clang][OpenMP][LoopTransformations] Fix incorrect number of generated loops for Tile and Reverse directives (PR #140532)

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llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang

Author: Walter J.T.V (eZWALT)

<details>
<summary>Changes</summary>

This patch is closely related to #<!-- -->139293 and addresses an existing issue in the loop transformation codebase. Specifically, it corrects the handling of the `NumGeneratedLoops` variable in `OMPLoopTransformationDirective` AST nodes and its inheritors (such as OMPUnrollDirective, OMPTileDirective, etc.).

Previously, this variable was inaccurately set for certain transformations like reverse or tile. While this did not lead to functional bugs, since the value was only checked to determine whether it was greater than zero or equal to zero, the inconsistency could introduce problems when supporting more complex directives in the future.

---
Full diff: https://github.com/llvm/llvm-project/pull/140532.diff


1 Files Affected:

- (modified) clang/include/clang/AST/StmtOpenMP.h (+4-2) 


``````````diff
diff --git a/clang/include/clang/AST/StmtOpenMP.h b/clang/include/clang/AST/StmtOpenMP.h
index 736bcabbad1f7..7ded194dd6eb2 100644
--- a/clang/include/clang/AST/StmtOpenMP.h
+++ b/clang/include/clang/AST/StmtOpenMP.h
@@ -5790,7 +5790,9 @@ class OMPReverseDirective final : public OMPLoopTransformationDirective {
   explicit OMPReverseDirective(SourceLocation StartLoc, SourceLocation EndLoc)
       : OMPLoopTransformationDirective(OMPReverseDirectiveClass,
                                        llvm::omp::OMPD_reverse, StartLoc,
-                                       EndLoc, 1) {}
+                                       EndLoc, 1) {
+    setNumGeneratedLoops(1);
+  }
 
   void setPreInits(Stmt *PreInits) {
     Data->getChildren()[PreInitsOffset] = PreInits;
@@ -5857,7 +5859,7 @@ class OMPInterchangeDirective final : public OMPLoopTransformationDirective {
       : OMPLoopTransformationDirective(OMPInterchangeDirectiveClass,
                                        llvm::omp::OMPD_interchange, StartLoc,
                                        EndLoc, NumLoops) {
-    setNumGeneratedLoops(3 * NumLoops);
+    setNumGeneratedLoops(NumLoops);
   }
 
   void setPreInits(Stmt *PreInits) {

``````````

</details>


https://github.com/llvm/llvm-project/pull/140532