Revert "Fix compilation with icx 2025"

This reverts commit 6d4c539.

Author: johguenther

openvkl/include/openvkl/VKLBackgroundUndefined.h

@@ -3,28 +3,11 @@
 
 #pragma once
 
+#include "ispc_cpp_interop.h"
+
 // A special value we use to distinguish an undefined field value. This could
 // be the result of sampling out of bounds, or sampling at a position in bounds
 // but not covered by any input data.
 // This value is a quiet NaN.
+#define VKL_BACKGROUND_UNDEFINED floatbits(0xFFC068B5u)
 
-#ifdef ISPC
-#define vkl_floatbits floatbits
-#else
-#if defined(__cplusplus)
-#include <cstdint>
-#include <cstring>
-using std::memcpy;
-#else
-#include <stdint.h>
-#include <string.h>
-#endif
-inline float vkl_floatbits(uint32_t bits)
-{
-  float fval;
-  memcpy(&fval, &bits, 4);
-  return fval;
-}
-#endif
-
-#define VKL_BACKGROUND_UNDEFINED vkl_floatbits(0xFFC068B5u)

openvkl/include/openvkl/ispc_cpp_interop.h

@@ -79,6 +79,42 @@
 
 #endif  // defined(__cplusplus)
 
+// -----------------------------------------------------------------------------
+// Standard library functions.
+// -----------------------------------------------------------------------------
+
+#if defined(__cplusplus)
+
+inline float floatbits(vkl_uint32 bits)
+{
+  VKL_INTEROP_STATIC_ASSERT(sizeof(float) == sizeof(vkl_uint32),
+                            "Float is not 4 Bytes.");
+  float fval                         = 0.f;
+  reinterpret_cast<char *>(&fval)[0] = reinterpret_cast<const char *>(&bits)[0];
+  reinterpret_cast<char *>(&fval)[1] = reinterpret_cast<const char *>(&bits)[1];
+  reinterpret_cast<char *>(&fval)[2] = reinterpret_cast<const char *>(&bits)[2];
+  reinterpret_cast<char *>(&fval)[3] = reinterpret_cast<const char *>(&bits)[3];
+  return fval;
+}
+
+inline vkl_uint32 intbits(float value)
+{
+  VKL_INTEROP_STATIC_ASSERT(sizeof(float) == sizeof(vkl_uint32),
+                            "Float is not 4 Bytes.");
+  vkl_uint32 ival = 0;
+  reinterpret_cast<char *>(&ival)[0] =
+      reinterpret_cast<const char *>(&value)[0];
+  reinterpret_cast<char *>(&ival)[1] =
+      reinterpret_cast<const char *>(&value)[1];
+  reinterpret_cast<char *>(&ival)[2] =
+      reinterpret_cast<const char *>(&value)[2];
+  reinterpret_cast<char *>(&ival)[3] =
+      reinterpret_cast<const char *>(&value)[3];
+  return ival;
+}
+
+#endif
+
 // -----------------------------------------------------------------------------
 // Helpers for univary definitions.
 // -----------------------------------------------------------------------------