Re: master b467bb5 4/4: Minimize ‘equal’ calls in (delete x vector)

[Pip Cet <pipcet@gmail.com>]

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On Sat, Aug 15, 2020 at 7:00 PM Pip Cet <pipcet@gmail.com> wrote:
> Indeed, we have
>
> (delete t [nil t]) => [t]
>
> which is nonsensical.

In fact, I'd prefer the attached: this is probably not worth worrying
too much about, so go with something straightforward?

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From 7e25be845efcb0ff6043b6100aaf81f6b8c9cafa Mon Sep 17 00:00:00 2001
From: Pip Cet <pipcet@gmail.com>
Date: Sat, 15 Aug 2020 19:20:27 +0000
Subject: [PATCH] Fix (delete t [nil t]).

---
 src/fns.c | 26 +++++---------------------
 1 file changed, 5 insertions(+), 21 deletions(-)

diff --git a/src/fns.c b/src/fns.c
index 069edbe90e..33c66aeef6 100644
--- a/src/fns.c
+++ b/src/fns.c
@@ -1749,35 +1749,19 @@ DEFUN ("delete", Fdelete, Sdelete, 2, 2, 0,
     {
       ptrdiff_t n = 0;
       ptrdiff_t size = ASIZE (seq);
-      ptrdiff_t neqbits_words = ((size + BITS_PER_BITS_WORD - 1)
-				 / BITS_PER_BITS_WORD);
       USE_SAFE_ALLOCA;
-      bits_word *neqbits = SAFE_ALLOCA (neqbits_words * sizeof *neqbits);
-      bits_word neqword = 0;
+      ptrdiff_t *posns = SAFE_ALLOCA (size * sizeof posns[0]);
 
       for (ptrdiff_t i = 0; i < size; i++)
-	{
-	  bool neq = NILP (Fequal (AREF (seq, i), elt));
-	  n += neq;
-	  neqbits[i / BITS_PER_BITS_WORD] = neqword = (neqword << 1) + neq;
-	}
+	if (NILP (Fequal (AREF (seq, i), elt)))
+	  posns[n++] = i;
 
       if (n != size)
 	{
 	  struct Lisp_Vector *p = allocate_vector (n);
 
-	  if (n != 0)
-	    {
-	      ptrdiff_t j = 0;
-	      for (ptrdiff_t i = 0; ; i++)
-		if (neqbits[i / BITS_PER_BITS_WORD]
-		    & ((bits_word) 1 << (i % BITS_PER_BITS_WORD)))
-		  {
-		    p->contents[j++] = AREF (seq, i);
-		    if (j == n)
-		      break;
-		  }
-	    }
+	  for (ptrdiff_t j = 0; j < n; j++)
+	    p->contents[j] = AREF (seq, posns[j]);
 
 	  XSETVECTOR (seq, p);
 	}
-- 
2.28.0