[llvm] improve debug messages in delinearization and dependence analysis (PR #156339)

[Ryotaro Kasuga via llvm-commits]

================
@@ -787,22 +805,38 @@ void printDelinearization(raw_ostream &O, Function *F, LoopInfo *LI,
                                 SE->getElementSize(&Inst));
     }
 
-      if (IsDelinearizationFailed()) {
-        O << "failed to delinearize\n";
-        continue;
-      }
+    if (IsDelinearizationFailed()) {
+      O << "failed to delinearize\n";
+      continue;
+    }
 
-      O << "Base offset: " << *BasePointer << "\n";
-      O << "ArrayDecl[UnknownSize]";
-      int Size = Subscripts.size();
-      for (int i = 0; i < Size - 1; i++)
+    O << "Base offset: " << *BasePointer << "\n";
+    O << "ArrayDecl";
+
+    // Print [Unknown] when the outermost dimension of the array is not known.
+    // Sizes[NumSizes - 1] is the array element size.
+    int NumSubscripts = Subscripts.size();
+    int NumSizes = Sizes.size();
+    if (NumSizes == NumSubscripts)
+      O << "[UnknownSize]";
+
+    // Handle different size relationships between Subscripts and Sizes.
+    if (NumSizes > 0) {
+      // Print array dimensions (all but the last size, which is element
+      // size).
+      for (int i = 0; i < NumSizes - 1; i++)
         O << "[" << *Sizes[i] << "]";
-      O << " with elements of " << *Sizes[Size - 1] << " bytes.\n";
 
-      O << "ArrayRef";
-      for (int i = 0; i < Size; i++)
-        O << "[" << *Subscripts[i] << "]";
-      O << "\n";
+      // Print element size (last element in Sizes array).
+      O << " with elements of " << *Sizes[NumSizes - 1] << " bytes.\n";
+    } else {
+      O << " unknown sizes.\n";
+    }
+
+    O << "ArrayRef";
+    for (int i = 0; i < NumSubscripts; i++)
+      O << "[" << *Subscripts[i] << "]";
+    O << "\n";
----------------
kasuga-fj wrote:

These changes don't seem relevant to "improve debug messages". Especially, if I understand correctly, the condition `NumSizes == NumSubscripts` is always true in the current implementation. If these changes are necessary for later PRs, it would be better to move them to those PRs.

https://github.com/llvm/llvm-project/pull/156339