From: Nathan Chancellor <natechancellor@gmail.com>
To: Jani Nikula <jani.nikula@linux.intel.com>,
Joonas Lahtinen <joonas.lahtinen@linux.intel.com>,
Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org,
linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com,
Nathan Chancellor <natechancellor@gmail.com>
Subject: [PATCH v2] drm/i915: Disable -Wtautological-constant-out-of-range-compare
Date: Mon, 10 Feb 2020 23:13:39 -0700 [thread overview]
Message-ID: <20200211061338.23666-1-natechancellor@gmail.com> (raw)
In-Reply-To: <20200211050808.29463-1-natechancellor@gmail.com>
A recent commit in clang added -Wtautological-compare to -Wall, which is
enabled for i915 so we see the following warning:
../drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c:1485:22: warning:
result of comparison of constant 576460752303423487 with expression of
type 'unsigned int' is always false
[-Wtautological-constant-out-of-range-compare]
if (unlikely(remain > N_RELOC(ULONG_MAX)))
~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~
This warning only happens on x86_64 but that check is relevant for
32-bit x86 so we cannot remove it. -Wtautological-compare on a whole has
good warnings but this one is not really relevant for the kernel because
of all of the different configurations that are used to build the
kernel. When -Wtautological-compare is enabled for the kernel, this
option will remain disabled so do that for i915 now.
Link: https://github.com/ClangBuiltLinux/linux/issues/778
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
---
v1 -> v2: https://lore.kernel.org/lkml/20200211050808.29463-1-natechancellor@gmail.com/
* Fix patch application due to basing on a local tree that had
-Wuninitialized turned on. Can confirm that patch applies on
latest -next now.
drivers/gpu/drm/i915/Makefile | 1 +
1 file changed, 1 insertion(+)
diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
index b8c5f8934dbd..159355eb43a9 100644
--- a/drivers/gpu/drm/i915/Makefile
+++ b/drivers/gpu/drm/i915/Makefile
@@ -22,6 +22,7 @@ subdir-ccflags-y += $(call cc-disable-warning, sign-compare)
subdir-ccflags-y += $(call cc-disable-warning, sometimes-uninitialized)
subdir-ccflags-y += $(call cc-disable-warning, initializer-overrides)
subdir-ccflags-y += $(call cc-disable-warning, uninitialized)
+subdir-ccflags-y += $(call cc-disable-warning, tautological-constant-out-of-range-compare)
subdir-ccflags-$(CONFIG_DRM_I915_WERROR) += -Werror
# Fine grained warnings disable
--
2.25.0
next prev parent reply other threads:[~2020-02-11 6:15 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-11 5:08 [PATCH] drm/i915: Disable -Wtautological-constant-out-of-range-compare Nathan Chancellor
2020-02-11 6:13 ` Nathan Chancellor [this message]
2020-02-11 9:41 ` [PATCH v2] " Michel Dänzer
2020-02-11 20:39 ` Nathan Chancellor
2020-02-12 8:52 ` Michel Dänzer
2020-02-12 17:07 ` Nathan Chancellor
2020-02-12 17:17 ` Michel Dänzer
2020-02-13 14:37 ` [Intel-gfx] " Jani Nikula
2020-02-13 21:48 ` Nathan Chancellor
2020-02-13 22:05 ` Jani Nikula
2020-02-13 22:43 ` Nick Desaulniers
2020-02-13 23:27 ` Nathan Chancellor
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