Subzero: Update tests and build scripts for sandboxing.

runtime/szrt.c

 //===- subzero/runtime/szrt.c - Subzero runtime source ----------*- C++ -*-===//
 //
 //                        The Subzero Code Generator
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
-// This file implements the runtime helper routines that are needed by
-// Subzero.  This needs to be compiled by some non-Subzero compiler.
+// This file implements wrappers for particular bitcode instructions
+// that are too uncommon and complex for a particular target to bother
+// implementing directly in Subzero target lowering.  This needs to be
+// compiled by some non-Subzero compiler.
 //
 //===----------------------------------------------------------------------===//
 
 #include <stdint.h>
 #include <stdlib.h>
 
-uint32_t cvtftoui32(float value) { return (uint32_t)value; }
+// TODO(stichnot): The various NaN cross tests try to map Subzero's
+// undefined behavior to the same as llc's undefined behavior, as
+// observed by the cross tests.  This will have to be kept up to date
+// with any future changes to llc, and may also have to be different
+// for different targets.  It would be better to find a more
+// appropriate set of llc options when building the Subzero runtime.
+//
+// We test for NaN using "value==value" instead of using isnan(value)
+// to avoid an external dependency on fpclassify().
 
-uint32_t cvtdtoui32(double value) { return (uint32_t)value; }
+uint32_t cvtftoui32(float value) {
+  if (value == value) // NaNaN
+    return (uint32_t)value;
+  return 0x80000000;
+}
+
+uint32_t cvtdtoui32(double value) {
+  if (value == value) // NaNaN
+    return (uint32_t)value;
+  return 0x80000000;
+}
 
 int64_t cvtftosi64(float value) { return (int64_t)value; }
 
 int64_t cvtdtosi64(double value) { return (int64_t)value; }
 
 uint64_t cvtftoui64(float value) { return (uint64_t)value; }
 
 uint64_t cvtdtoui64(double value) { return (uint64_t)value; }
 
 float cvtui32tof(uint32_t value) { return (float)value; }
 
 float cvtsi64tof(int64_t value) { return (float)value; }
 
 float cvtui64tof(uint64_t value) { return (float)value; }
 
 double cvtui32tod(uint32_t value) { return (double)value; }
 
 double cvtsi64tod(int64_t value) { return (double)value; }
 
 double cvtui64tod(uint64_t value) { return (double)value; }
 
 /* TODO(stichnot):
    Sz_bitcast_v8i1_to_i8
    Sz_bitcast_v16i1_to_i16
    Sz_bitcast_i8_to_v8i1
    Sz_bitcast_i16_to_v16i1
 */