[Mlir-commits] [mlir] [mlir][ptr] Add `ptr.ptr_diff` operation (PR #157354)

[Mehdi Amini]

================
@@ -415,6 +415,63 @@ def Ptr_PtrAddOp : Pointer_Op<"ptr_add", [
   }];
 }
 
+//===----------------------------------------------------------------------===//
+// PtrDiffOp
+//===----------------------------------------------------------------------===//
+
+def Ptr_PtrDiffOp : Pointer_Op<"ptr_diff", [
+    Pure, AllTypesMatch<["lhs", "rhs"]>, SameOperandsAndResultShape
+  ]> {
+  let summary = "Pointer difference operation";
+  let description = [{
+    The `ptr_diff` operation computes the difference between two pointers,
+    returning an integer or index value representing the number of bytes
+    between them. This difference is always computed using signed arithmetic.
+
+    The operation supports both scalar and shaped types with value semantics:
+    - When both operands are scalar: produces a single difference value
+    - When both are shaped: performs element-wise subtraction,
+      shapes must be the same
+
+    The operation also supports the following flags:
+    - `none`: No flags are set.
+    - `nuw`: No Unsigned Wrap, if the subtraction causes an unsigned overflow,
+      the result is a poison value.
----------------
joker-eph wrote:

```suggestion
    - `nuw`: No Unsigned Wrap, if the subtraction causes an unsigned overflow
      (that is: the result would be negative), the result is a poison value.
```

https://github.com/llvm/llvm-project/pull/157354