master 82c089f 3/6: regex-emacs: omit regstart tests and regend set

[Paul Eggert]

branch: master
commit 82c089f532ede12c5811daacae5f824703ff8a7e
Author: Paul Eggert <eggert@cs.ucla.edu>
Commit: Paul Eggert <eggert@cs.ucla.edu>

    regex-emacs: omit regstart tests and regend set
    
    * src/regex-emacs.c (PUSH_FAILURE_REG, POP_FAILURE_REG_OR_COUNT)
    (re_match_2_internal): Add some assertions that regstart
    is set whenever regend is.
    (re_match_2_internal): Omit two unnecessary REG_UNSET (regstart ...)s
    and one unnecessary assignment to regend.
---
 src/regex-emacs.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/src/regex-emacs.c b/src/regex-emacs.c
index da73f58..b9c157d 100644
--- a/src/regex-emacs.c
+++ b/src/regex-emacs.c
@@ -982,6 +982,7 @@ do {                                                        
                \
   ENSURE_FAIL_STACK(3);                                                        
\
   DEBUG_PRINT ("    Push reg %"PRIdPTR" (spanning %p -> %p)\n",                
\
               n, regstart[n], regend[n]);                              \
+  eassert (REG_UNSET (regstart[n]) <= REG_UNSET (regend[n]));          \
   PUSH_FAILURE_POINTER (regstart[n]);                                  \
   PUSH_FAILURE_POINTER (regend[n]);                                    \
   PUSH_FAILURE_INT (n);                                                        
\
@@ -1019,6 +1020,7 @@ do {                                                      
                \
     {                                                                  \
       regend[pfreg] = POP_FAILURE_POINTER ();                          \
       regstart[pfreg] = POP_FAILURE_POINTER ();                                
\
+      eassert (REG_UNSET (regstart[pfreg]) <= REG_UNSET (regend[pfreg])); \
       DEBUG_PRINT ("     Pop reg %ld (spanning %p -> %p)\n",           \
                   pfreg, regstart[pfreg], regend[pfreg]);              \
     }                                                                  \
@@ -4122,6 +4124,8 @@ re_match_2_internal (struct re_pattern_buffer *bufp,
                    {
                      regstart[reg] = best_regstart[reg];
                      regend[reg] = best_regend[reg];
+                     eassert (REG_UNSET (regstart[reg])
+                              <= REG_UNSET (regend[reg]));
                    }
                }
            } /* d != end_match_2 */
@@ -4169,7 +4173,9 @@ re_match_2_internal (struct re_pattern_buffer *bufp,
 
              for (ptrdiff_t reg = 1; reg < num_regs; reg++)
                {
-                 if (REG_UNSET (regstart[reg]) || REG_UNSET (regend[reg]))
+                 eassert (REG_UNSET (regstart[reg])
+                          <= REG_UNSET (regend[reg]));
+                 if (REG_UNSET (regend[reg]))
                    regs->start[reg] = regs->end[reg] = -1;
                  else
                    {
@@ -4374,7 +4380,6 @@ re_match_2_internal (struct re_pattern_buffer *bufp,
          PUSH_FAILURE_REG (*p);
 
          regstart[*p] = d;
-         regend[*p] = NULL;    /* probably unnecessary.  -sm  */
          DEBUG_PRINT ("  regstart: %td\n", POINTER_TO_OFFSET (regstart[*p]));
 
          /* Move past the register number and inner group count.  */
@@ -4419,7 +4424,8 @@ re_match_2_internal (struct re_pattern_buffer *bufp,
            DEBUG_PRINT ("EXECUTING duplicate %d.\n", regno);
 
            /* Can't back reference a group which we've never matched.  */
-           if (REG_UNSET (regstart[regno]) || REG_UNSET (regend[regno]))
+           eassert (REG_UNSET (regstart[regno]) <= REG_UNSET (regend[regno]));
+           if (REG_UNSET (regend[regno]))
              goto fail;
 
            /* Where in input to try to start matching.  */