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drm/amd/display: fix overflow on MIN_I64 definition

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[ Upstream commit 6ae0632d17759852c07e2d1e0a31c728eb6ba246 ]

The definition of MIN_I64 in bw_fixed.c can cause gcc to whinge about
integer overflow, because it is treated as a positive value, which is
then negated. The temporary positive value is not necessarily
representable.

This causes the following warning:
../drivers/gpu/drm/amd/amdgpu/../display/dc/dml/calcs/bw_fixed.c:30:19:
warning: integer overflow in expression ‘-9223372036854775808’ of type
‘long long int’ results in ‘-9223372036854775808’ [-Woverflow]
  30 |         (int64_t)(-(1LL << 63))
     |                   ^

Writing out (-MAX_I64 - 1) works instead.

Signed-off-by: David Gow <davidgow@google.com>
Signed-off-by: Tales Aparecida <tales.aparecida@gmail.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
David Gow 2022-08-11 17:43:26 -03:00 committed by Greg Kroah-Hartman
parent 8052612b9d
commit 3e1876bb78
1 changed files with 3 additions and 3 deletions
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6
drivers/gpu/drm/amd/display/dc/calcs/bw_fixed.c
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@ -26,12 +26,12 @@
#include "bw_fixed.h"
#define MIN_I64 \
(int64_t)(-(1LL << 63))
#define MAX_I64 \
(int64_t)((1ULL << 63) - 1)
#define MIN_I64 \
(-MAX_I64 - 1)
#define FRACTIONAL_PART_MASK \
((1ULL << BW_FIXED_BITS_PER_FRACTIONAL_PART) - 1)