[libcxx-commits] [libcxx] r369693 - [libc++] Fix broken <random> test

[Louis Dionne via libcxx-commits]

Author: ldionne
Date: Thu Aug 22 12:35:46 2019
New Revision: 369693

URL: http://llvm.org/viewvc/llvm-project?rev=369693&view=rev
Log:
[libc++] Fix broken <random> test

In r369429, I hoisted a floating point computation to a variable in order
to remove a warning. However, it turns out this doesn't play well with
floating point arithmetic. This commit reverts r369429 and instead casts
the result of the floating point computation to remove the warning.

Whether hoisting the computaiton to a variable should give the same
result can be investigated independently.

Modified:
    libcxx/trunk/test/std/numerics/rand/rand.util/rand.util.canonical/generate_canonical.pass.cpp

Modified: libcxx/trunk/test/std/numerics/rand/rand.util/rand.util.canonical/generate_canonical.pass.cpp
URL: http://llvm.org/viewvc/llvm-project/libcxx/trunk/test/std/numerics/rand/rand.util/rand.util.canonical/generate_canonical.pass.cpp?rev=369693&r1=369692&r2=369693&view=diff
==============================================================================
--- libcxx/trunk/test/std/numerics/rand/rand.util/rand.util.canonical/generate_canonical.pass.cpp (original)
+++ libcxx/trunk/test/std/numerics/rand/rand.util/rand.util.canonical/generate_canonical.pass.cpp Thu Aug 22 12:35:46 2019
@@ -19,78 +19,85 @@
 
 int main(int, char**)
 {
-    typedef std::minstd_rand0 E;
-    auto range = E::max() - E::min();
-
     {
+        typedef std::minstd_rand0 E;
         typedef float F;
         E r;
         F f = std::generate_canonical<F, 0>(r);
-        assert(f == truncate_fp((16807 - E::min()) / (range + F(1))));
+        assert(f == truncate_fp((16807 - E::min()) / (static_cast<F>(E::max() - E::min()) + F(1))));
     }
     {
+        typedef std::minstd_rand0 E;
         typedef float F;
         E r;
         F f = std::generate_canonical<F, 1>(r);
-        assert(f == truncate_fp((16807 - E::min()) / (range + F(1))));
+        assert(f == truncate_fp((16807 - E::min()) / (static_cast<F>(E::max() - E::min()) + F(1))));
     }
     {
+        typedef std::minstd_rand0 E;
         typedef float F;
         E r;
         F f = std::generate_canonical<F, std::numeric_limits<F>::digits - 1>(r);
-        assert(f == truncate_fp((16807 - E::min()) / (range + F(1))));
+        assert(f == truncate_fp((16807 - E::min()) / (static_cast<F>(E::max() - E::min()) + F(1))));
     }
     {
+        typedef std::minstd_rand0 E;
         typedef float F;
         E r;
         F f = std::generate_canonical<F, std::numeric_limits<F>::digits>(r);
-        assert(f == truncate_fp((16807 - E::min()) / (range + F(1))));
+        assert(f == truncate_fp((16807 - E::min()) / (static_cast<F>(E::max() - E::min()) + F(1))));
     }
     {
+        typedef std::minstd_rand0 E;
         typedef float F;
         E r;
         F f = std::generate_canonical<F, std::numeric_limits<F>::digits + 1>(r);
-        assert(f == truncate_fp((16807 - E::min()) / (range + F(1))));
+        assert(f == truncate_fp((16807 - E::min()) / (static_cast<F>(E::max() - E::min()) + F(1))));
     }
 
     {
+        typedef std::minstd_rand0 E;
         typedef double F;
         E r;
         F f = std::generate_canonical<F, 0>(r);
-        assert(f == truncate_fp((16807 - E::min()) / (range + F(1))));
+        assert(f == truncate_fp((16807 - E::min()) / (static_cast<F>(E::max() - E::min()) + F(1))));
     }
     {
+        typedef std::minstd_rand0 E;
         typedef double F;
         E r;
         F f = std::generate_canonical<F, 1>(r);
-        assert(f == truncate_fp((16807 - E::min()) / (range + F(1))));
+        assert(f == truncate_fp((16807 - E::min()) / (static_cast<F>(E::max() - E::min()) + F(1))));
     }
     {
+        typedef std::minstd_rand0 E;
         typedef double F;
         E r;
         F f = std::generate_canonical<F, std::numeric_limits<F>::digits - 1>(r);
         assert(f == truncate_fp(
             (16807 - E::min() +
-            (282475249 - E::min()) * (range + F(1))) /
-            ((range + F(1)) * (range + F(1)))));
+            (282475249 - E::min()) * (static_cast<F>(E::max() - E::min()) + F(1))) /
+            ((static_cast<F>(E::max() - E::min()) + F(1)) * (static_cast<F>(E::max() - E::min()) + F(1)))));
     }
     {
+        typedef std::minstd_rand0 E;
         typedef double F;
         E r;
         F f = std::generate_canonical<F, std::numeric_limits<F>::digits>(r);
         assert(f == truncate_fp(
             (16807 - E::min() +
-            (282475249 - E::min()) * (range + F(1))) /
-            ((range + F(1)) * (range + F(1)))));
+            (282475249 - E::min()) * (static_cast<F>(E::max() - E::min()) + F(1))) /
+            ((static_cast<F>(E::max() - E::min()) + F(1)) * (static_cast<F>(E::max() - E::min()) + F(1)))));
     }
     {
+        typedef std::minstd_rand0 E;
         typedef double F;
         E r;
         F f = std::generate_canonical<F, std::numeric_limits<F>::digits + 1>(r);
         assert(f == truncate_fp(
             (16807 - E::min() +
-            (282475249 - E::min()) * (range + F(1))) /
-            ((range + F(1)) * (range + F(1)))));
+            (282475249 - E::min()) * (static_cast<F>(E::max() - E::min()) + F(1))) /
+            ((static_cast<F>(E::max() - E::min()) + F(1)) * (static_cast<F>(E::max() - E::min()) + F(1)))));
     }
 
   return 0;