From 865d50ebd6656ef9ea3d0281cae2da53c21052f3 Mon Sep 17 00:00:00 2001
From: millert <>
Date: Wed, 17 May 2017 20:28:35 +0000
Subject: Approximate nlgn instead of using libm.  The same approximation may
 be used in qsort.c in a later commit.

---
 src/regress/lib/libc/qsort/Makefile     |  4 +---
 src/regress/lib/libc/qsort/qsort_test.c | 14 +++++++-------
 2 files changed, 8 insertions(+), 10 deletions(-)

diff --git a/src/regress/lib/libc/qsort/Makefile b/src/regress/lib/libc/qsort/Makefile
index d3c4e2baa2..9062e26f95 100644
--- a/src/regress/lib/libc/qsort/Makefile
+++ b/src/regress/lib/libc/qsort/Makefile
@@ -1,9 +1,7 @@
-#       $OpenBSD: Makefile,v 1.1 2017/05/17 14:47:06 millert Exp $
+#       $OpenBSD: Makefile,v 1.2 2017/05/17 20:28:35 millert Exp $
 
 PROG=	qsort_test
 CFLAGS+=-Wall
-LDADD+=	-lm
-DPADD+=	${LIBM}
 
 qsort-regress: ${PROG}
 	./${PROG}
diff --git a/src/regress/lib/libc/qsort/qsort_test.c b/src/regress/lib/libc/qsort/qsort_test.c
index b23f3e6190..3b36eb06b4 100644
--- a/src/regress/lib/libc/qsort/qsort_test.c
+++ b/src/regress/lib/libc/qsort/qsort_test.c
@@ -18,7 +18,6 @@
 #include <stdlib.h>
 #include <string.h>
 #include <setjmp.h>
-#include <math.h>
 #include <err.h>
 
 /*
@@ -235,16 +234,17 @@ run_tests(int m, int n)
 {
 	int *x, *y, *z;
 	int ret = 0;
-	double nlgn;
+	int idx, nlgn = 0;
 	enum distribution dist;
 
 	/*
-	 * The expected number of compares is A * n * log2(n)
-	 * where A is between 1 and 2.  If A is greater than 1.5
-	 * we'll print a warning.  If A is greater than 10 we
-	 * abort the test since qsort has probably gone quadratic.
+	 * We expect A*n*lg(n) compares where A is between 1 and 2.
+	 * For A > 1.5, print a warning.
+	 * For A > 10 abort the test since qsort has probably gone quadratic.
 	 */
-	nlgn = n * log2(n);
+	for (idx = n - 1; idx > 0; idx >>= 1)
+	    nlgn++;
+	nlgn *= n;
 	max_compares = nlgn * 1.5;
 	abrt_compares = nlgn * 10;
 
-- 
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