roastduck opened a new issue #5245: lower_warp_memory not working URL: https://github.com/apache/incubator-tvm/issues/5245 `src/tir/transforms/lower_warp_memory.cc` transforms memory accesses in "warp" scope to "local" scope, and generates warp shuffle primitives. I found it indeed transformed the scope to "local", but it failed to generate the shuffle primitives for me. To reproduce: ```python import tvm import topi import numpy as np from topi.util import get_const_tuple dtype = "float32" target = "cuda" n = m = 32 a = tvm.te.placeholder((m,), name="a", dtype=dtype) b = tvm.te.compute((n,), lambda i: a[(i + 1) % m]) with tvm.target.cuda(): s = tvm.te.create_schedule(b.op) th_x = tvm.te.thread_axis("threadIdx.x") blk_x = tvm.te.thread_axis("blockIdx.x") i, = b.op.axis blk, th = s[b].split(i, nparts=1) s[b].bind(blk, blk_x) s[b].bind(th, th_x) a_cache = s.cache_read(a, "warp", b) a_axis, = a_cache.op.axis s[a_cache].bind(a_axis, th_x) s[a_cache].compute_at(s[b], blk) print(tvm.lower(s, [a, b], target, simple_mode=True)) compute = tvm.build(s, [a, b], target, name="run") print(compute.imported_modules[0].get_source()) ``` The output was: ``` produce compute { // attr [iter_var(blockIdx.x, , blockIdx.x)] thread_extent = 1 // attr [a.warp] storage_scope = "warp" allocate a.warp[float32 * 32] produce a.warp { // attr [iter_var(threadIdx.x, , threadIdx.x)] thread_extent = 32 a.warp[threadIdx.x] = a[threadIdx.x] } // attr [iter_var(threadIdx.x, , threadIdx.x)] thread_extent = 32 compute[threadIdx.x] = a.warp[floormod((threadIdx.x + 1), 32)] } extern "C" __global__ void run_kernel0(void* __restrict__ a, void* __restrict__ compute) { float a_warp[1]; a_warp[(0)] = (( float*)a)[(((int)threadIdx.x))]; (( float*)compute)[(((int)threadIdx.x))] = a_warp[(((((int)threadIdx.x) + 1) & 31))]; } ``` You will find that the shuffle primitive is missing. Instead, it directly stores the unshuffled data. There is a unit test for this pass in `tests/python/unittest/test_tir_transform_lower_warp_memory.py`, in which it only asserts the "local" scope, but it does not check the overall correctness. So the test is too weak to discover the problem. I also traced the lowering pass using GDB. I found the `CallNode::make` to create that primitive in Line 248 is actually invoked. But the primitive is lost somewhere.
---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected] With regards, Apache Git Services
