E6031

Error · Topology/Hardware

E6031 — A tensor shape that folds to a negative extent, or whose size is more than 2^63 - 1 bytes, the most an allocation can ask for. The size is known, and it is not one the generated code can allocate: it would wrap.

What the compiler reports

Error[E6031] at [[@LINE+1]]:11: `Tensor<f32, [2, -3]>` cannot be allocated: one of its extents is negative
Error[E6031] at [[@LINE+1]]:14: `Tensor<f32, [2305843009213693952]>` cannot be allocated: its size is more than 2^63 - 1 bytes

The fragments the test suite holds the compiler to. An ellipsis marks text the test does not constrain; the emitted message also carries a source location.

A program that triggers it

//
// Part of the Vx Project, under the Apache License v2.0 with LLVM Exceptions.
// See LICENSE for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//
// A tensor size written as a negative number is refused, and so is a tensor of 2^63 bytes:
// it fits in 64 bits, but an allocation can ask for at most 2^63 - 1 bytes. A tensor of
// 2^62 bytes is allowed.

fn main() -> i32 {
  let b = Tensor<f32, [2, -3]>::new();
  // 2^61 elements of 4 bytes each is 2^63 bytes.
  let huge = Tensor<f32, [2305843009213693952]>::new();
  // 2^61 elements of 2 bytes each is 2^62 bytes.
  // FITS-NOT: Tensor<f16
  let fits = Tensor<f16, [2147483648, 1073741824]>::new();
  return 0;
}

From tests/frontend/fail/tensor_size_negative_or_too_large.vx, which asserts this diagnostic on every commit.

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