Convert sqrt functions into sqrt instructions when -ffast-math is in effect.

When -ffast-math is in effect (on Linux, at least), clang defines
__FINITE_MATH_ONLY__ > 0 when including <math.h>. This causes the
preprocessor to include <bits/math-finite.h>, which renames the sqrt functions.
For instance, "sqrt" is renamed as "__sqrt_finite". 

This patch adds the 3 new names in such a way that they will be treated
as equivalent to their respective original names.





git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@182739 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index aae1179..f686784 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -5562,6 +5562,9 @@
       case LibFunc::sqrt:
       case LibFunc::sqrtf:
       case LibFunc::sqrtl:
+      case LibFunc::sqrt_finite:
+      case LibFunc::sqrtf_finite:
+      case LibFunc::sqrtl_finite:
         if (visitUnaryFloatCall(I, ISD::FSQRT))
           return;
         break;