Change NaN with large number

Reviewed By: emilsjolander

Differential Revision: D6969537

fbshipit-source-id: bdc09eaf703e0d313ca65c25a4fb44c99203d9bf

ReactAndroid/src/main/java/com/facebook/yoga/YogaConstants.java

@@ -9,12 +9,29 @@ package com.facebook.yoga;
 
 public class YogaConstants {
 
-  public static final float UNDEFINED = Float.NaN;
+  /**
+   * Large positive number signifies that the property(float) is undefined. Earlier we used to have
+   * YGundefined as NAN, but the downside of this is that we can't use -ffast-math compiler flag as
+   * it assumes all floating-point calculation involve and result into finite numbers. For more
+   * information regarding -ffast-math compiler flag in clang, have a look at
+   * https://clang.llvm.org/docs/UsersManual.html#cmdoption-ffast-math
+   */
+  public static final float UNDEFINED = (float) (10E20);
 
   public static boolean shouldUseFastMath = false;
 
   public static boolean isUndefined(float value) {
-    return Float.compare(value, UNDEFINED) == 0;
+    // Value of a float in the case of it being not defined is 10.1E20. Earlier it used to be NAN,
+    // the benefit of which
+    // was that if NAN is involved in any mathematical expression the result was NAN. But since we
+    // want to have `-ffast-math`
+    // flag being used by compiler which assumes that the floating point values are not NAN and Inf,
+    // we represent YGUndefined as 10.1E20.
+    // But now if YGUndefined is involved in any mathematical operations this value(10.1E20) would
+    // change.
+    // So the following check makes sure that if the value is outside a range (-10E8, 10E8) then it
+    // is undefined.
+    return (Float.compare(value, (float) 10E8) >= 0 || Float.compare(value, (float) -10E8) <= 0);
   }
 
   public static boolean isUndefined(YogaValue value) {

ReactAndroid/src/main/java/com/facebook/yoga/YogaNode.java

@@ -652,11 +652,11 @@ public class YogaNode implements Cloneable {
     }
 
     return mMeasureFunction.measure(
-          this,
-          width,
-          YogaMeasureMode.fromInt(widthMode),
-          height,
-          YogaMeasureMode.fromInt(heightMode));
+        this,
+        width,
+        YogaMeasureMode.fromInt(widthMode),
+        height,
+        YogaMeasureMode.fromInt(heightMode));
   }
 
   private native void jni_YGNodeSetHasBaselineFunc(long nativePointer, boolean hasMeasureFunc);