On 22/03/2024 11:56, Thomas Schwinge wrote:
Hi Andrew!
On 2024-03-21T13:39:53+0000, Andrew Stubbs <a...@baylibre.com> wrote:
CUmode "on" is the setting for compatibility with GCN and CDNA devices.
--- a/gcc/config/gcn/gcn-hsa.h
+++ b/gcc/config/gcn/gcn-hsa.h
@@ -107,6 +107,7 @@ extern unsigned int gcn_local_sym_hash (const char *name);
"%{" NO_XNACK XNACKOPT "} " \
"%{" NO_SRAM_ECC SRAMOPT "} " \
"%{march=gfx1030|march=gfx1100:-mattr=+wavefrontsize64} " \
+ "%{march=gfx1030|march=gfx1100:-mattr=+cumode} " \
"-filetype=obj"
Is this just general housekeeping, or should I be seeing any kind of
change in the GCN target '-march=gfx1100' test results? (I'm not.)
I'm pretty sure cumode is the default, but defaults can change and now
we're future-proof. The option doesn't change the ELF flags at all.
The opposite of cumode allows more than 16 wavefronts in a workgroup,
but they can't physically share a single LDS memory so it would break
OpenACC broadcasting and reductions, and OpenMP libgomp team metadata.
Also "cgroup" low-latency memory allocation.
Andrew
