tools/perf/build: Remove the volatile-register-var feature check

Namhyung Kim noticed that the volatile-register-var feature check
is superfluous:

 > The gcc manpage says this warning is enabled by -Wall, and we add -Wall
 > to CFLAGS before doing feature checks.  So all gcc versions that support
 > -Wvolatile-register-var enables it by default without this check and
 > older gcc versions will always fail the feature check.

Remove it - this will further speed up feature checks.

Reported-by: Namhyung Kim <namhyung@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/config/Makefile b/tools/perf/config/Makefile
index d2079220ff87b9a3aeb28a28db51e9efc6fd9ddb..c516d6ba67163654fbcbe150292ebdf8a1fa2f7e 100644 (file)
--- a/tools/perf/config/Makefile
+++ b/tools/perf/config/Makefile
@@ -132,8 +132,7 @@ CORE_FEATURE_TESTS =                        \
        libunwind                       \
        on-exit                         \
        stackprotector                  \
-       stackprotector-all              \
-       volatile-register-var
+       stackprotector-all
 
 #
 # So here we detect whether test-all was rebuilt, to be able
@@ -203,10 +202,6 @@ ifeq ($(feature-stackprotector), 1)
   CFLAGS += -Wstack-protector
 endif
 
-ifeq ($(feature-volatile-register-var), 1)
-  CFLAGS += -Wvolatile-register-var
-endif
-
 ifeq ($(DEBUG),0)
   ifeq ($(feature-fortify-source), 1)
     CFLAGS += -D_FORTIFY_SOURCE=2

diff --git a/tools/perf/config/feature-checks/Makefile b/tools/perf/config/feature-checks/Makefile
index cf33596c73000b76c73474676ec699a6b72e59fe..2eb83467cca2d3fb51d936b0d14a5048a0548167 100644 (file)
--- a/tools/perf/config/feature-checks/Makefile
+++ b/tools/perf/config/feature-checks/Makefile
@@ -25,8 +25,7 @@ FILES=                                        \
        test-libunwind                  \
        test-on-exit                    \
        test-stackprotector-all         \
-       test-stackprotector             \
-       test-volatile-register-var
+       test-stackprotector
 
 CC := $(CC) -MD
 
@@ -37,7 +36,7 @@ BUILD = $(CC) $(LDFLAGS) -o $(OUTPUT)$@ $@.c
 ###############################
 
 test-all:
-       $(BUILD) -Werror -fstack-protector -fstack-protector-all -Wvolatile-register-var -O2 -Werror -D_FORTIFY_SOURCE=2 -ldw -lelf -lnuma -lunwind -lunwind-x86_64 -lelf -laudit -I/usr/include/slang -lslang $(shell pkg-config --libs --cflags gtk+-2.0 2>/dev/null) $(FLAGS_PERL_EMBED) $(FLAGS_PYTHON_EMBED) -DPACKAGE='"perf"' -lbfd -ldl
+       $(BUILD) -Werror -fstack-protector -fstack-protector-all -O2 -Werror -D_FORTIFY_SOURCE=2 -ldw -lelf -lnuma -lunwind -lunwind-x86_64 -lelf -laudit -I/usr/include/slang -lslang $(shell pkg-config --libs --cflags gtk+-2.0 2>/dev/null) $(FLAGS_PERL_EMBED) $(FLAGS_PYTHON_EMBED) -DPACKAGE='"perf"' -lbfd -ldl
 
 test-hello:
        $(BUILD)
@@ -48,9 +47,6 @@ test-stackprotector-all:
 test-stackprotector:
        $(BUILD) -Werror -fstack-protector
 
-test-volatile-register-var:
-       $(BUILD) -Werror -Wvolatile-register-var
-
 test-fortify-source:
        $(BUILD) -O2 -Werror -D_FORTIFY_SOURCE=2