[PATCH 2/2] drm/i915: Silence smatch for cmdparser

Chris Wilson
2017-01-20T21:45:35Z

drivers/gpu/drm/i915/i915_cmd_parser.c:808:23: error: not an lvalue
drivers/gpu/drm/i915/i915_cmd_parser.c:811:23: error: not an lvalue
drivers/gpu/drm/i915/i915_cmd_parser.c:814:23: error: not an lvalue
drivers/gpu/drm/i915/i915_cmd_parser.c:808:23: error: not an lvalue
drivers/gpu/drm/i915/i915_cmd_parser.c:811:23: error: not an lvalue
drivers/gpu/drm/i915/i915_cmd_parser.c:814:23: error: not an lvalue
drivers/gpu/drm/i915/i915_cmd_parser.c:808:23: error: not an lvalue
drivers/gpu/drm/i915/i915_cmd_parser.c:811:23: error: not an lvalue
drivers/gpu/drm/i915/i915_cmd_parser.c:814:23: error: not an lvalue
drivers/gpu/drm/i915/i915_cmd_parser.c:808:23: error: not an lvalue
drivers/gpu/drm/i915/i915_cmd_parser.c:811:23: error: not an lvalue
drivers/gpu/drm/i915/i915_cmd_parser.c:814:23: error: not an lvalue

If we move the shift into each case not only do we kill the warning from
smatch, but we shrink the code slightly:

text data bss dec hex filename
1267906 20587 3168 1291661 13b58d before
1267890 20587 3168 1291645 13b57d after

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
---
drivers/gpu/drm/i915/i915_cmd_parser.c | 13 +++----------
1 file changed, 3 insertions(+), 10 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_cmd_parser.c b/drivers/gpu/drm/i915/i915_cmd_parser.c
index 420bbc220f35..650ee34f5786 100644
--- a/drivers/gpu/drm/i915/i915_cmd_parser.c
+++ b/drivers/gpu/drm/i915/i915_cmd_parser.c
@@ -800,22 +800,15 @@ struct cmd_node {
*/
static inline u32 cmd_header_key(u32 x)
{
- u32 shift;
-
switch (x >> INSTR_CLIENT_SHIFT) {
default:
case INSTR_MI_CLIENT:
- shift = STD_MI_OPCODE_SHIFT;
- break;
+ return x >> STD_MI_OPCODE_SHIFT;
case INSTR_RC_CLIENT:
- shift = STD_3D_OPCODE_SHIFT;
- break;
+ return x >> STD_3D_OPCODE_SHIFT;
case INSTR_BC_CLIENT:
- shift = STD_2D_OPCODE_SHIFT;
- break;
+ return x >> STD_2D_OPCODE_SHIFT;
}
-
- return x >> shift;
}

static int init_hash_table(struct intel_engine_cs *engine,
--
2.11.0