If I compile a compute kernel with a call to texture.read(), it fails with the following error: "Error Domain=AGXMetalG13X Code=3 "Encountered unlowered function call to air.get_read_sampler" UserInfo={NSLocalizedDescription=Encountered unlowered function call to air.get_read_sampler}."
This error occurs on both macOS and iOS 26 Beta 5, but not when running on a simulator or in a playground. It does not occur on a macOS Sequoia VM. It occurs whether I use the old metal 3 or new metal 4 compilation method.
A workaround would be to use a sampler, but according to the feature tables, all platforms support reading from textures of all formats.
Below is a minimal example which produces the error:
let device = MTLCreateSystemDefaultDevice()!
let library = device.makeDefaultLibrary()!
let computeFunction = library.makeFunction(name: "compute_test")!
do {
let pipeline = try device.makeComputePipelineState(function: computeFunction)
debugPrint(pipeline)
} catch {
debugPrint("Metal 3 failed with error:\n\(error)")
}
#import <metal_stdlib>
using namespace metal;
kernel void compute_test(uint2 gid [[thread_position_in_grid]],
texture2d<float, access::read> in [[texture(0)]],
texture2d<float, access::write> out [[texture(1)]]) {
out.write(in.read(gid), gid);
}
I filed feedback FB19530049.
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