From c7b4b5fe001136d13331d4a9aa63b4b43d20c452 Mon Sep 17 00:00:00 2001
From: Linus Groh <mail@linusgroh.de>
Date: Mon, 6 Apr 2020 14:23:09 +0100
Subject: [PATCH] LibM: Fix ceil() and ceilf() for negative numbers

These functions are using a naive approach: casting double/float to int
and returning the result + 1. That increment by one must only happen for
positive input values though.
---
 Libraries/LibM/math.cpp | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/Libraries/LibM/math.cpp b/Libraries/LibM/math.cpp
index a43a156612..b3c89e4a26 100644
--- a/Libraries/LibM/math.cpp
+++ b/Libraries/LibM/math.cpp
@@ -384,8 +384,12 @@ float ceilf(float value)
 {
     // FIXME: Please fix me. I am naive.
     int as_int = (int)value;
-    if (value == (float)as_int) {
-        return (float)as_int;
+    if (value == (float)as_int)
+        return as_int;
+    if (value < 0) {
+        if (as_int == 0)
+            return -0;
+        return as_int;
     }
     return as_int + 1;
 }
@@ -394,8 +398,12 @@ double ceil(double value)
 {
     // FIXME: Please fix me. I am naive.
     int as_int = (int)value;
-    if (value == (double)as_int) {
-        return (double)as_int;
+    if (value == (double)as_int)
+        return as_int;
+    if (value < 0) {
+        if (as_int == 0)
+            return -0;
+        return as_int;
     }
     return as_int + 1;
 }