tools: Drop nonsensical -O6

-O6 is very much not-a-thing. Really, this should've been dropped
entirely in 49b3cd3 ("tools: Set the maximum optimization level
according to the compiler being used") instead of just passing it for
not-Clang.

Just collapse it down to -O3, instead of "-O6 unless Clang, in which case
-O3".

GCC interprets > -O3 as -O3. It doesn't even interpret > -O3 as -Ofast,
which is a good thing, given -Ofast has specific (non-)requirements for
code built using it. So, this does nothing except look a bit daft.

Remove the silliness and also save a few lines in the Makefiles accordingly.

Reviewed-by: Ian Rogers <irogers@google.com>
Reviewed-by: Jesper Juhl <jesperjuhl76@gmail.com>
Signed-off-by: Sam James <sam@gentoo.org>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Bill Wendling <morbo@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Justin Stitt <justinstitt@google.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: llvm@lists.linux.dev
Link: https://lore.kernel.org/r/4f01524fa4ea91c7146a41e26ceaf9dae4c127e4.1725821201.git.sam@gentoo.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Author: thesamesam

tools/lib/api/Makefile

@@ -31,11 +31,7 @@ CFLAGS := $(EXTRA_WARNINGS) $(EXTRA_CFLAGS)
 CFLAGS += -ggdb3 -Wall -Wextra -std=gnu99 -U_FORTIFY_SOURCE -fPIC
 
 ifeq ($(DEBUG),0)
-ifeq ($(CC_NO_CLANG), 0)
   CFLAGS += -O3
-else
-  CFLAGS += -O6
-endif
 endif
 
 ifeq ($(DEBUG),0)

tools/lib/subcmd/Makefile

@@ -38,10 +38,8 @@ endif
 
 ifeq ($(DEBUG),1)
   CFLAGS += -O0
-else ifeq ($(CC_NO_CLANG), 0)
-  CFLAGS += -O3
 else
-  CFLAGS += -O6
+  CFLAGS += -O3
 endif
 
 # Treat warnings as errors unless directed not to

tools/lib/symbol/Makefile

@@ -31,11 +31,7 @@ CFLAGS := $(EXTRA_WARNINGS) $(EXTRA_CFLAGS)
 CFLAGS += -ggdb3 -Wall -Wextra -std=gnu11 -U_FORTIFY_SOURCE -fPIC
 
 ifeq ($(DEBUG),0)
-ifeq ($(CC_NO_CLANG), 0)
   CFLAGS += -O3
-else
-  CFLAGS += -O6
-endif
 endif
 
 ifeq ($(DEBUG),0)

tools/perf/Makefile.config

@@ -233,11 +233,7 @@ endif
 
 ifeq ($(DEBUG),0)
 CORE_CFLAGS += -DNDEBUG=1
-ifeq ($(CC_NO_CLANG), 0)
-  CORE_CFLAGS += -O3
-else
-  CORE_CFLAGS += -O6
-endif
+CORE_CFLAGS += -O3
 else
   CORE_CFLAGS += -g
   CXXFLAGS += -g