Omnibus removal of register declarations

This removes most register declarations in C code (and accompanying
documentation) in the Perl core.  Retained are those in the ext
directory, Configure, and those that are associated with assembly
language.

See:
http://stackoverflow.com/questions/314994/whats-a-good-example-of-register-variable-usage-in-c

which says, in part:

There is no good example of register usage when using modern compilers
(read: last 10+ years) because it almost never does any good and can do
some bad. When you use register, you are telling the compiler "I know
how to optimize my code better than you do" which is almost never the
case. One of three things can happen when you use register:

    The compiler ignores it, this is most likely. In this case the only
        harm is that you cannot take the address of the variable in the
        code.
    The compiler honors your request and as a result the code runs slower.
    The compiler honors your request and the code runs faster, this is the least likely scenario.

Even if one compiler produces better code when you use register, there
is no reason to believe another will do the same. If you have some
critical code that the compiler is not optimizing well enough your best
bet is probably to use assembler for that part anyway but of course do
the appropriate profiling to verify the generated code is really a
problem first.

1 files changed, 12 insertions, 12 deletions

diff --git a/doio.c b/doio.c
index e5098b7002..94f2003b65 100644
--- a/doio.c
+++ b/doio.c
@@ -66,7 +66,7 @@ Perl_do_openn(pTHX_ GV *gv, register const char *oname, I32 len, int as_raw,
 	      I32 num_svs)
 {
     dVAR;
-    register IO * const io = GvIOn(gv);
+    IO * const io = GvIOn(gv);
     PerlIO *saveifp = NULL;
     PerlIO *saveofp = NULL;
     int savefd = -1;
@@ -709,7 +709,7 @@ PerlIO *
 Perl_nextargv(pTHX_ register GV *gv)
 {
     dVAR;
-    register SV *sv;
+    SV *sv;
 #ifndef FLEXFILENAMES
     int filedev;
     int fileino;
@@ -994,7 +994,7 @@ bool
 Perl_do_eof(pTHX_ GV *gv)
 {
     dVAR;
-    register IO * const io = GvIO(gv);
+    IO * const io = GvIO(gv);
 
     PERL_ARGS_ASSERT_DO_EOF;
 
@@ -1040,7 +1040,7 @@ Perl_do_tell(pTHX_ GV *gv)
 {
     dVAR;
     IO *const io = GvIO(gv);
-    register PerlIO *fp;
+    PerlIO *fp;
 
     PERL_ARGS_ASSERT_DO_TELL;
 
@@ -1061,7 +1061,7 @@ Perl_do_seek(pTHX_ GV *gv, Off_t pos, int whence)
 {
     dVAR;
     IO *const io = GvIO(gv);
-    register PerlIO *fp;
+    PerlIO *fp;
 
     if (io && (fp = IoIFP(io))) {
 #ifdef ULTRIX_STDIO_BOTCH
@@ -1080,7 +1080,7 @@ Perl_do_sysseek(pTHX_ GV *gv, Off_t pos, int whence)
 {
     dVAR;
     IO *const io = GvIO(gv);
-    register PerlIO *fp;
+    PerlIO *fp;
 
     PERL_ARGS_ASSERT_DO_SYSSEEK;
 
@@ -1437,8 +1437,8 @@ bool
 Perl_do_exec3(pTHX_ const char *incmd, int fd, int do_report)
 {
     dVAR;
-    register const char **a;
-    register char *s;
+    const char **a;
+    char *s;
     char *buf;
     char *cmd;
     /* Make a copy so we can change it */
@@ -1574,8 +1574,8 @@ I32
 Perl_apply(pTHX_ I32 type, register SV **mark, register SV **sp)
 {
     dVAR;
-    register I32 val;
-    register I32 tot = 0;
+    I32 val;
+    I32 tot = 0;
     const char *const what = PL_op_name[type];
     const char *s;
     STRLEN len;
@@ -1648,7 +1648,7 @@ Perl_apply(pTHX_ I32 type, register SV **mark, register SV **sp)
     case OP_CHOWN:
 	APPLY_TAINT_PROPER();
 	if (sp - mark > 2) {
-            register I32 val2;
+            I32 val2;
 	    val = SvIVx(*++mark);
 	    val2 = SvIVx(*++mark);
 	    APPLY_TAINT_PROPER();
@@ -1725,7 +1725,7 @@ nothing in the core.
 	     */
 	    while (++mark <= sp) {
 		I32 proc;
-		register unsigned long int __vmssts;
+		unsigned long int __vmssts;
 		SvGETMAGIC(*mark);
 		if (!(SvIOK(*mark) || SvNOK(*mark) || looks_like_number(*mark)))
 		    Perl_croak(aTHX_ "Can't kill a non-numeric process ID");