Fix: GCC warns about possibly uninitialized data in signal.cpp

When compiling with '-Og', GCC warns about variables that are
initialized by reference in the condition of a 'while' loop.

This commit silences the warning by explicitly initializing the
variables in question to their respective 'invalid value' markers,
which will most likely be optimized out when the compiler realizes
the values are never used.

1 files changed, 7 insertions, 7 deletions

diff --git a/src/signal.cpp b/src/signal.cpp
index 068ca6193..9b17e51dc 100644
--- a/src/signal.cpp
+++ b/src/signal.cpp
@@ -268,10 +268,10 @@ static SigFlags ExploreSegment(Owner owner)
 {
 	SigFlags flags = SF_NONE;
 
-	TileIndex tile;
-	DiagDirection enterdir;
+	TileIndex tile = INVALID_TILE; // Stop GCC from complaining about a possibly uninitialized variable (issue #8280).
+	DiagDirection enterdir = INVALID_DIAGDIR;
 
-	while (_tbdset.Get(&tile, &enterdir)) {
+	while (_tbdset.Get(&tile, &enterdir)) { // tile and enterdir are initialized here, unless I'm mistaken.
 		TileIndex oldtile = tile; // tile we are leaving
 		DiagDirection exitdir = enterdir == INVALID_DIAGDIR ? INVALID_DIAGDIR : ReverseDiagDir(enterdir); // expected new exit direction (for straight line)
 
@@ -407,8 +407,8 @@ static SigFlags ExploreSegment(Owner owner)
  */
 static void UpdateSignalsAroundSegment(SigFlags flags)
 {
-	TileIndex tile;
-	Trackdir trackdir;
+	TileIndex tile = INVALID_TILE; // Stop GCC from complaining about a possibly uninitialized variable (issue #8280).
+	Trackdir trackdir = INVALID_TRACKDIR;
 
 	while (_tbuset.Get(&tile, &trackdir)) {
 		assert(HasSignalOnTrackdir(tile, trackdir));
@@ -474,8 +474,8 @@ static SigSegState UpdateSignalsInBuffer(Owner owner)
 	bool first = true;  // first block?
 	SigSegState state = SIGSEG_FREE; // value to return
 
-	TileIndex tile;
-	DiagDirection dir;
+	TileIndex tile = INVALID_TILE; // Stop GCC from complaining about a possibly uninitialized variable (issue #8280).
+	DiagDirection dir = INVALID_DIAGDIR;
 
 	while (_globset.Get(&tile, &dir)) {
 		assert(_tbuset.IsEmpty());