From 6f7651b9b611b2e5283f69a633f047f4ab9ea7e0 Mon Sep 17 00:00:00 2001
From: Dimitry Andric <dim@FreeBSD.org>
Date: Wed, 21 Dec 2011 17:01:13 +0000
Subject: [PATCH] When building with clang, disable -Wshift-count-negative and
 -Wshift-count-overflow for sys/dev/ath/ath_hal/ah_regdomain.c, as it gets
 multiple instances of the following warnings:

In file included from sys/dev/ath/ath_hal/ah_regdomain.c:99:
sys/dev/ath/ath_hal/ah_regdomain/ah_rd_domains.h:69:15: warning: shift count is negative [-Wshift-count-negative]
         .chan11a               = BM4(F1_4950_4980,
                                  ^~~~~~~~~~~~~~~~~
sys/dev/ath/ath_hal/ah_regdomain/ah_rd_domains.h:41:4: note: expanded from:
          W1(_fa) | W1(_fb) | W1(_fc) | W1(_fd) }
          ^
sys/dev/ath/ath_hal/ah_regdomain/ah_rd_domains.h:34:45: note: expanded from:
        (((_a) > 63 && (_a) < 128 ? (((uint64_t) 1)<<((_a)-64)) : (uint64_t) 0))
                                                   ^ ~~~~~~~~~

and:

In file included from sys/dev/ath/ath_hal/ah_regdomain.c:99:
sys/dev/ath/ath_hal/ah_regdomain/ah_rd_domains.h:629:15: error: shift count >= width of type [-Werror,-Wshift-count-overflow]
         .chan11a               = BM4(W2_5260_5320,
                                  ^~~~~~~~~~~~~~~~~
sys/dev/ath/ath_hal/ah_regdomain/ah_rd_domains.h:40:34: note: expanded from:
        { W0(_fa) | W0(_fb) | W0(_fc) | W0(_fd),                        \
                                        ^
sys/dev/ath/ath_hal/ah_regdomain/ah_rd_domains.h:32:44: note: expanded from:
        (((_a) >= 0 && (_a) < 64 ? (((uint64_t) 1)<<(_a)) : (uint64_t) 0))
                                                  ^ ~~~~

Both warnings are false positives, caused by LLVM PR 10030.  For global
initializations, clang fails to detect that the branch of the ternary
operator causing the warning is dead.

MFC after:	1 week
---
 sys/conf/files   | 2 +-
 sys/conf/kern.mk | 2 ++
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/sys/conf/files b/sys/conf/files
index 7d8ce4bad65a..55fd4b2b3481 100644
--- a/sys/conf/files
+++ b/sys/conf/files
@@ -613,7 +613,7 @@ dev/ath/ath_hal/ah_eeprom_9287.c \
 	optional ath_hal | ath_ar9287 \
 	compile-with "${NORMAL_C} -I$S/dev/ath"
 dev/ath/ath_hal/ah_regdomain.c	optional ath \
-	compile-with "${NORMAL_C} -I$S/dev/ath"
+	compile-with "${NORMAL_C} ${NO_WSHIFT_COUNT_NEGATIVE} ${NO_WSHIFT_COUNT_OVERFLOW} -I$S/dev/ath"
 # ar5210
 dev/ath/ath_hal/ar5210/ar5210_attach.c		optional ath_hal | ath_ar5210 \
 	compile-with "${NORMAL_C} -I$S/dev/ath -I$S/dev/ath/ath_hal"
diff --git a/sys/conf/kern.mk b/sys/conf/kern.mk
index 745b0e183eee..c53d88e91ce1 100644
--- a/sys/conf/kern.mk
+++ b/sys/conf/kern.mk
@@ -17,6 +17,8 @@ CWARNFLAGS?=	-Wall -Wredundant-decls -Wnested-externs -Wstrict-prototypes \
 .if ${CC:T:Mclang} == "clang"
 NO_WCONSTANT_CONVERSION=	-Wno-constant-conversion
 NO_WARRAY_BOUNDS=		-Wno-array-bounds
+NO_WSHIFT_COUNT_NEGATIVE=	-Wno-shift-count-negative
+NO_WSHIFT_COUNT_OVERFLOW=	-Wno-shift-count-overflow
 .endif
 
 #