PR68474: Fix tree-call-cdce.c:use_internal_fn

We'd call gen_shrink_wrap_conditions for functions that it can't handle
but edom_only_function can.

Tested on x86_64-linux-gnu.

gcc/
	PR tree-optimization/68474
	* tree-call-cdce.c (use_internal_fn): Protect call to
	gen_shrink_wrap_conditions.

gcc/testsuite/
	PR tree-optimization/68474
	* gcc.dg/pr68474.c: New test.

From-SVN: r231115

gcc/ChangeLog

+2015-12-01  Richard Sandiford  <richard.sandiford@arm.com>
+
+	PR tree-optimization/68474
+	* tree-call-cdce.c (use_internal_fn): Protect call to
+	gen_shrink_wrap_conditions.
+
 2015-12-01  Christian Bruel  <christian.bruel@st.com>
 
 	PR target/68617

gcc/testsuite/ChangeLog

+2015-12-01  Richard Sandiford  <richard.sandiford@arm.com>
+
+	PR tree-optimization/68474
+	* gcc.dg/pr68474.c: New test.
+
 2015-12-01  Christian Bruel  <christian.bruel@st.com>
 
 	PR target/68617

gcc/testsuite/gcc.dg/pr68474.c

+/* { dg-options "-O -funsafe-math-optimizations" } */
+
+long double
+foo (long double d1, long double d2)
+{
+  return d1 || __builtin_significandl (d2);
+}

gcc/tree-call-cdce.c

@@ -959,7 +959,8 @@ use_internal_fn (gcall *call)
 {
   unsigned nconds = 0;
   auto_vec<gimple *, 12> conds;
-  gen_shrink_wrap_conditions (call, conds, &nconds);
+  if (can_test_argument_range (call))
+    gen_shrink_wrap_conditions (call, conds, &nconds);
   if (nconds == 0 && !edom_only_function (call))
     return false;