[Intel-gfx] [PATCH 2/2] drm/i915: Ensure intel_engine_init_execlist() builds with Clang

[Jani Nikula]

Clang build with UBSAN enabled leads to the following build error:

drivers/gpu/drm/i915/intel_engine_cs.o: In function `intel_engine_init_execlist':
drivers/gpu/drm/i915/intel_engine_cs.c:411: undefined reference to `__compiletime_assert_411'

Again, for this to work the code would first need to be inlined and then
constant folded, which doesn't work for Clang because semantic analysis
happens before optimization/inlining.

Use GEM_BUG_ON() instead of BUILD_BUG_ON().

v2: Use is_power_of_2() from log2.h (Chris)

References: http://mid.mail-archive.com/20181015203410.155997-1-swboyd@chromium.org
Reported-by: Stephen Boyd <swboyd at chromium.org>
Cc: Stephen Boyd <swboyd at chromium.org>
Cc: Chris Wilson <chris at chris-wilson.co.uk>
Signed-off-by: Jani Nikula <jani.nikula at intel.com>
---
 drivers/gpu/drm/i915/intel_engine_cs.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/intel_engine_cs.c b/drivers/gpu/drm/i915/intel_engine_cs.c
index f27dbe26bcc1..bc793b0c8806 100644
--- a/drivers/gpu/drm/i915/intel_engine_cs.c
+++ b/drivers/gpu/drm/i915/intel_engine_cs.c
@@ -466,7 +466,7 @@ static void intel_engine_init_execlist(struct intel_engine_cs *engine)
 	struct intel_engine_execlists * const execlists = &engine->execlists;
 
 	execlists->port_mask = 1;
-	BUILD_BUG_ON_NOT_POWER_OF_2(execlists_num_ports(execlists));
+	GEM_BUG_ON(!is_power_of_2(execlists_num_ports(execlists)));
 	GEM_BUG_ON(execlists_num_ports(execlists) > EXECLIST_MAX_PORTS);
 
 	execlists->queue_priority = INT_MIN;
-- 
2.11.0