-W-unreachable-code option added, alphabetic order of --list-warnings

doc/cc65.sgml

@@ -555,6 +555,8 @@ Here is a description of all the command line options:
         Warn when passing structs by value.
   <tag><tt/unknown-pragma/</tag>
         Warn about #pragmas that aren't recognized by cc65.
+  <tag><tt/unreachable-code/</tag>
+        Warn about unreachable code in cases of comparing constants, etc.
   <tag><tt/unused-label/</tag>
         Warn about unused labels.
   <tag><tt/unused-param/</tag>

src/cc65/error.c

@@ -71,12 +71,13 @@ IntStack WarnNoEffect       = INTSTACK(1);  /* - statements without an effect */
 IntStack WarnPointerSign    = INTSTACK(1);  /* - pointer conversion to pointer differing in signedness */
 IntStack WarnPointerTypes   = INTSTACK(1);  /* - pointer conversion to incompatible pointer type */
 IntStack WarnRemapZero      = INTSTACK(1);  /* - remapping character code zero */
+IntStack WarnReturnType     = INTSTACK(1);  /* - control reaches end of non-void function */
 IntStack WarnStructParam    = INTSTACK(0);  /* - structs passed by val */
 IntStack WarnUnknownPragma  = INTSTACK(1);  /* - unknown #pragmas */
+IntStack WarnUnreachableCode= INTSTACK(1);  /* - unreachable code */
 IntStack WarnUnusedLabel    = INTSTACK(1);  /* - unused labels */
 IntStack WarnUnusedParam    = INTSTACK(1);  /* - unused parameters */
 IntStack WarnUnusedVar      = INTSTACK(1);  /* - unused variables */
-IntStack WarnReturnType     = INTSTACK(1);  /* - control reaches end of non-void function */
 
 /* Map the name of a warning to the intstack that holds its state */
 typedef struct WarnMapEntry WarnMapEntry;
@@ -92,12 +93,13 @@ static WarnMapEntry WarnMap[] = {
     { &WarnPointerSign,         "pointer-sign"          },
     { &WarnPointerTypes,        "pointer-types"         },
     { &WarnRemapZero,           "remap-zero"            },
+    { &WarnReturnType,          "return-type"           },
     { &WarnStructParam,         "struct-param"          },
     { &WarnUnknownPragma,       "unknown-pragma"        },
+    { &WarnUnreachableCode,     "unreachable-code"      },
     { &WarnUnusedLabel,         "unused-label"          },
     { &WarnUnusedParam,         "unused-param"          },
     { &WarnUnusedVar,           "unused-var"            },
-    { &WarnReturnType,          "return-type"           },
 };
 
 Collection DiagnosticStrBufs;

src/cc65/error.h

@@ -68,12 +68,13 @@ extern IntStack WarnPointerSign;        /* - pointer conversion to pointer diffe
 extern IntStack WarnPointerTypes;       /* - pointer conversion to incompatible pointer type */
 extern IntStack WarnNoEffect;           /* - statements without an effect */
 extern IntStack WarnRemapZero;          /* - remapping character code zero */
+extern IntStack WarnReturnType;         /* - control reaches end of non-void function */
 extern IntStack WarnStructParam;        /* - structs passed by val */
 extern IntStack WarnUnknownPragma;      /* - unknown #pragmas */
+extern IntStack WarnUnreachableCode;    /* - unreachable code */
 extern IntStack WarnUnusedLabel;        /* - unused labels */
 extern IntStack WarnUnusedParam;        /* - unused parameters */
 extern IntStack WarnUnusedVar;          /* - unused variables */
-extern IntStack WarnReturnType;         /* - control reaches end of non-void function */
 
 /* Forward */
 struct StrBuf;

src/cc65/stmt.c

@@ -187,7 +187,7 @@ static int IfStatement (void)
         /* If the if expression was always true, the code in the else branch
         ** is never executed. Output a warning if this is the case.
         */
-        if (TestResult == TESTEXPR_TRUE) {
+        if (TestResult == TESTEXPR_TRUE && IS_Get (&WarnUnreachableCode)) {
             Warning ("Unreachable code");
         }