Change compiler optimizations to -O3 -flto (#11207)

Optimization update from -O2 to -O3 -flto gives up to 5% performance gain
in 'redis-benchmarks-spec-client-runner' tests geomean where GCC 9.4.0 is used for build

* Fix for false-positive warning in bitops.c
   Warning appeared with O3, on CentOS during inlininig procedure
* Fixed unitialized streamID within streamTrim() (#1)

Co-authored-by: filipe oliveira <filipecosta.90@gmail.com>

src/Makefile

@@ -15,7 +15,7 @@
 release_hdr := $(shell sh -c './mkreleasehdr.sh')
 uname_S := $(shell sh -c 'uname -s 2>/dev/null || echo not')
 uname_M := $(shell sh -c 'uname -m 2>/dev/null || echo not')
-OPTIMIZATION?=-O2
+OPTIMIZATION?=-O3 -flto
 DEPENDENCY_TARGETS=hiredis linenoise lua hdr_histogram
 NODEPS:=clean distclean
 

src/bitops.c

@@ -1180,7 +1180,9 @@ void bitfieldGeneric(client *c, int flags) {
                     addReplyNull(c);
                 }
             } else {
-                uint64_t oldval, newval, wrapped, retval;
+                /* Initialization of 'wrapped' is required to avoid
+                * false-positive warning "-Wmaybe-uninitialized" */
+                uint64_t oldval, newval, retval, wrapped = 0;
                 int overflow;
 
                 oldval = getUnsignedBitfield(o->ptr,thisop->offset,

src/t_stream.c

@@ -747,7 +747,7 @@ int64_t streamTrim(stream *s, streamAddTrimArgs *args) {
             streamDecodeID(ri.key, &master_id);
 
             /* Read last ID. */
-            streamID last_id;
+            streamID last_id = {0,0};
             lpGetEdgeStreamID(lp, 0, &master_id, &last_id);
 
             /* We can remove the entire node id its last ID < 'id' */