[llvm] [polly] [delinearize] Extract array dimensions from alloca and global declarations (PR #156342)

[Sebastian Pop via llvm-commits]

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@@ -408,6 +425,145 @@ void llvm::computeAccessFunctions(ScalarEvolution &SE, const SCEV *Expr,
   });
 }
 
+/// Backward compatibility wrapper for the old 4-parameter version.
+void llvm::computeAccessFunctions(ScalarEvolution &SE, const SCEV *Expr,
+                                  SmallVectorImpl<const SCEV *> &Subscripts,
+                                  SmallVectorImpl<const SCEV *> &Sizes) {
+  // Use the element size from the last element in Sizes array (legacy behavior)
+  if (Sizes.empty()) {
+    Subscripts.clear();
+    return;
+  }
+  const SCEV *ElementSize = Sizes.back();
+  computeAccessFunctions(SE, Expr, Subscripts, Sizes, ElementSize);
+}
+
+/// Extract array dimensions from alloca or global variable declarations.
+/// Returns true if array dimensions were successfully extracted.
+static bool
+extractArrayInfoFromAllocaOrGlobal(ScalarEvolution &SE, Value *BasePtr,
+                                   SmallVectorImpl<const SCEV *> &Sizes,
+                                   const SCEV *ElementSize) {
+  // Clear output vector.
+  Sizes.clear();
+
+  LLVM_DEBUG(
+      dbgs() << "extractArrayInfoFromAllocaOrGlobal called with BasePtr: "
+             << *BasePtr << "\n");
+
+  // Distinguish between simple array accesses and complex pointer arithmetic.
+  // Only apply array_info extraction to direct array accesses to avoid
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sebpop wrote:

This is a remnant of the previous attempt that was to attach an array_info bundle to assumes.  We may want to revive that patch and instead of attaching the array_info bundle to an assume, we will attach the array_info bundles to allocas and to globals.  Right now array_info is the same as 'type' of alloca and globals.

https://github.com/llvm/llvm-project/pull/156342