From d91f7b06defc2ad4b64e164307dbcf728af5139d Mon Sep 17 00:00:00 2001
From: Kleis Auke Wolthuizen <github@kleisauke.nl>
Date: Mon, 4 Nov 2024 13:33:02 +0100
Subject: [PATCH] reduce: prefer use of `VIPS_FABS()` (#4243)

To ensure we handle negative zero (-0.0) correctly.

(cherry picked from commit 852fd7c69ef6903be838fb10937994388fd81263)
---
 libvips/resample/templates.h | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/libvips/resample/templates.h b/libvips/resample/templates.h
index 49a56b5ae5..e652149aa3 100644
--- a/libvips/resample/templates.h
+++ b/libvips/resample/templates.h
@@ -361,8 +361,7 @@ static double inline filter(double x);
 template <>
 double inline filter<VIPS_KERNEL_LINEAR>(double x)
 {
-	if (x < 0.0)
-		x = -x;
+	x = VIPS_FABS(x);
 
 	if (x < 1.0)
 		return 1.0 - x;