diff --git a/layout/reftests/image/reftest.list b/layout/reftests/image/reftest.list
index a89951c47ae5..6e74c24b451f 100644
--- a/layout/reftests/image/reftest.list
+++ b/layout/reftests/image/reftest.list
@@ -33,7 +33,6 @@ fuzzy(1,1) == image-orientation-from-image.html?180&flip image-orientation-ref.h
 fuzzy(1,1) == image-orientation-from-image.html?270&flip image-orientation-ref.html?270&flip
 
 # Tests for image-orientation used with an explicit orientation:
-fuzzy(1,1) == image-orientation-explicit.html?-900     image-orientation-ref.html?180
 fuzzy(1,1) == image-orientation-explicit.html?0        image-orientation-ref.html?0
 fuzzy(1,1) == image-orientation-explicit.html?90       image-orientation-ref.html?90
 fuzzy(1,1) == image-orientation-explicit.html?180      image-orientation-ref.html?180
@@ -44,7 +43,6 @@ fuzzy(1,1) == image-orientation-explicit.html?180&flip image-orientation-ref.htm
 fuzzy(1,1) == image-orientation-explicit.html?270&flip image-orientation-ref.html?270&flip
 
 # Tests for image-orientation used with non-axis-aligned angles:
-fuzzy(1,1) == image-orientation-explicit.html?-46      image-orientation-ref.html?270
 fuzzy(1,1) fails-if(styloVsGecko||stylo) == image-orientation-explicit.html?-45      image-orientation-ref.html?0
 fuzzy(1,1) == image-orientation-explicit.html?-15      image-orientation-ref.html?0
 fuzzy(1,1) == image-orientation-explicit.html?15       image-orientation-ref.html?0
diff --git a/layout/style/nsStyleStruct.h b/layout/style/nsStyleStruct.h
index 19f2e058c10a..c8fa7cb8df13 100644
--- a/layout/style/nsStyleStruct.h
+++ b/layout/style/nsStyleStruct.h
@@ -2030,9 +2030,6 @@ struct nsStyleImageOrientation
 
     // Compute the final angle value, rounding to the closest quarter turn.
     double roundedAngle = fmod(aRadians, 2 * M_PI);
-    if (roundedAngle < 0) {
-      roundedAngle = roundedAngle + 2 * M_PI;
-    }
     if      (roundedAngle < 0.25 * M_PI) { orientation = ANGLE_0;  }
     else if (roundedAngle < 0.75 * M_PI) { orientation = ANGLE_90; }
     else if (roundedAngle < 1.25 * M_PI) { orientation = ANGLE_180;}