FIX: avoid overflow on overflow check in toms748_solve safe_div

mckib2 · mckib2 · commit 9b0a6be371bb · 2023-02-04T22:16:41.000-07:00
diff --git a/include/boost/math/tools/toms748_solve.hpp b/include/boost/math/tools/toms748_solve.hpp
@@ -160,7 +160,8 @@ inline T safe_div(T num, T denom, T r)
 
    if(fabs(denom) < 1)
    {
-      if(fabs(denom * tools::max_value<T>()) <= fabs(num))
+      static const T inv_max_value = 1.0 / tools::max_value<T>();
+      if(fabs(denom) <= inv_max_value * fabs(num))
          return r;
    }
    return num / denom;

Original file line number	Diff line number	Diff line change
`@@ -160,7 +160,8 @@ inline T safe_div(T num, T denom, T r)`
`160`	`160`
`161`	`161`	`if(fabs(denom) < 1)`
`162`	`162`	`{`
`163`		`- if(fabs(denom * tools::max_value<T>()) <= fabs(num))`
	`163`	`+ static const T inv_max_value = 1.0 / tools::max_value<T>();`
	`164`	`+ if(fabs(denom) <= inv_max_value * fabs(num))`
`164`	`165`	`return r;`
`165`	`166`	`}`
`166`	`167`	`return num / denom;`