[glibc/azanella/qsort-fixes] stdlib: qsort: Move some macros to inline function

[Adhemerval Zanella <azanella@sourceware.org>]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=44b3018f45aa08f8facf7728e2a275846c120f2c

commit 44b3018f45aa08f8facf7728e2a275846c120f2c
Author: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Date:   Thu Sep 2 10:34:24 2021 -0300

    stdlib: qsort: Move some macros to inline function
    
    Change the macro PUSH and POP and rmeove the macro STACK_NOT_EMPTY.

Diff:
---
 stdlib/qsort.c | 33 +++++++++++++++++++++++----------
 1 file changed, 23 insertions(+), 10 deletions(-)

diff --git a/stdlib/qsort.c b/stdlib/qsort.c
index a6c78d6101..60ca3b48b0 100644
--- a/stdlib/qsort.c
+++ b/stdlib/qsort.c
@@ -114,15 +114,28 @@ typedef struct
     char *hi;
   } stack_node;
 
-/* The next 4 #defines implement a very fast in-line stack abstraction. */
 /* The stack needs log (total_elements) entries (we could even subtract
    log(MAX_THRESH)).  Since total_elements has type size_t, we get as
    upper bound for log (total_elements):
    bits per byte (CHAR_BIT) * sizeof(size_t).  */
-#define STACK_SIZE	(CHAR_BIT * sizeof (size_t))
-#define PUSH(low, high)	((void) ((top->lo = (low)), (top->hi = (high)), ++top))
-#define	POP(low, high)	((void) (--top, (low = top->lo), (high = top->hi)))
-#define	STACK_NOT_EMPTY	(stack < top)
+enum { STACK_SIZE = CHAR_BIT * sizeof (size_t) };
+
+static inline stack_node *
+push (stack_node *top, char *lo, char *hi)
+{
+  top->lo = lo;
+  top->hi = hi;
+  return ++top;
+}
+
+static inline stack_node *
+pop (stack_node *top, char **lo, char **hi)
+{
+  --top;
+  *lo = top->lo;
+  *hi = top->hi;
+  return top;
+}
 
 
 /* Order size using quicksort.  This implementation incorporates
@@ -228,9 +241,9 @@ _quicksort (void *const pbase, size_t total_elems, size_t size,
       stack_node stack[STACK_SIZE];
       stack_node *top = stack;
 
-      PUSH (NULL, NULL);
+      top = push (top, NULL, NULL);
 
-      while (STACK_NOT_EMPTY)
+      while (stack < top)
         {
           char *left_ptr;
           char *right_ptr;
@@ -295,7 +308,7 @@ _quicksort (void *const pbase, size_t total_elems, size_t size,
             {
               if ((size_t) (hi - left_ptr) <= max_thresh)
 		/* Ignore both small partitions. */
-                POP (lo, hi);
+		top = pop (top, &lo, &hi);
               else
 		/* Ignore small left partition. */
                 lo = left_ptr;
@@ -306,13 +319,13 @@ _quicksort (void *const pbase, size_t total_elems, size_t size,
           else if ((right_ptr - lo) > (hi - left_ptr))
             {
 	      /* Push larger left partition indices. */
-              PUSH (lo, right_ptr);
+	      top = push (top, lo, right_ptr);
               lo = left_ptr;
             }
           else
             {
 	      /* Push larger right partition indices. */
-              PUSH (left_ptr, hi);
+	      top = push (top, left_ptr, hi);
               hi = right_ptr;
             }
         }