Description: Fix build with LLVM/Clang 8

Origin: (partly) FreeBSD https://svnweb.freebsd.org/ports/head/lang/beignet/files/patch-llvm8?view=markup
Author: Jan Beich, Rebecca N. Palmer

--- a/backend/src/CMakeLists.txt
+++ b/backend/src/CMakeLists.txt
@@ -168,6 +168,7 @@ add_dependencies(gbe beignet_bitcode)
 endif (NOT (USE_STANDALONE_GBE_COMPILER STREQUAL "true"))
 
 add_library(gbeinterp SHARED gbe_bin_interpreter.cpp)
+target_link_libraries(gbeinterp ${LLVM_MODULE_LIBS} ${LLVM_SYSTEM_LIBS})
 
 if (LLVM_VERSION_NODOT VERSION_EQUAL 34)
   find_library(TERMINFO NAMES tinfo ncurses)
--- a/backend/src/llvm/llvm_gen_backend.cpp
+++ b/backend/src/llvm/llvm_gen_backend.cpp
@@ -3073,14 +3073,22 @@ namespace gbe
 
 
   static unsigned getChildNo(BasicBlock *bb) {
+#if LLVM_VERSION_MAJOR < 8
     TerminatorInst *term = bb->getTerminator();
+#else
+    Instruction *term = bb->getTerminator();
+#endif
     return term->getNumSuccessors();
   }
 
   // return NULL if index out-range of children number
   static BasicBlock *getChildPossible(BasicBlock *bb, unsigned index) {
 
+#if LLVM_VERSION_MAJOR < 8
     TerminatorInst *term = bb->getTerminator();
+#else
+    Instruction *term = bb->getTerminator();
+#endif
     unsigned childNo = term->getNumSuccessors();
     BasicBlock *child = NULL;
     if(index < childNo) {
--- a/backend/src/backend/gen_register.hpp
+++ b/backend/src/backend/gen_register.hpp
@@ -225,6 +225,7 @@ namespace gbe
                        uint32_t width,
                        uint32_t hstride)
     {
+      this->value.reg = 0;//avoid subgroup crash
       this->type = type;
       this->file = file;
       this->nr = nr;
--- a/backend/src/libocl/tmpl/ocl_integer.tmpl.cl
+++ b/backend/src/libocl/tmpl/ocl_integer.tmpl.cl
@@ -216,13 +216,14 @@ OVERLOADABLE ulong mad_sat(ulong a, ulon
   return __gen_ocl_mad_sat(a, b, c);
 }
 
-OVERLOADABLE uchar __rotate_left(uchar x, uchar y) { return (x << y) | (x >> (8 - y)); }
+// the 'volatile' is to make the LLVM optimizer leave these alone, as it would convert them to intrinsics (fshl/fshr) that we don't implement
+OVERLOADABLE uchar __rotate_left(uchar x, uchar y) { volatile uchar z; z = (x << y); return z | (x >> (8 - y)); }
 OVERLOADABLE char __rotate_left(char x, char y) { return __rotate_left((uchar)x, (uchar)y); }
-OVERLOADABLE ushort __rotate_left(ushort x, ushort y) { return (x << y) | (x >> (16 - y)); }
+OVERLOADABLE ushort __rotate_left(ushort x, ushort y) { volatile ushort z; z = (x << y); return z | (x >> (16 - y)); }
 OVERLOADABLE short __rotate_left(short x, short y) { return __rotate_left((ushort)x, (ushort)y); }
-OVERLOADABLE uint __rotate_left(uint x, uint y) { return (x << y) | (x >> (32 - y)); }
+OVERLOADABLE uint __rotate_left(uint x, uint y) { volatile uint z; z = (x << y); return z | (x >> (32 - y)); }
 OVERLOADABLE int __rotate_left(int x, int y) { return __rotate_left((uint)x, (uint)y); }
-OVERLOADABLE ulong __rotate_left(ulong x, ulong y) { return (x << y) | (x >> (64 - y)); }
+OVERLOADABLE ulong __rotate_left(ulong x, ulong y) { volatile ulong z; z = (x << y); return z | (x >> (64 - y)); }
 OVERLOADABLE long __rotate_left(long x, long y) { return __rotate_left((ulong)x, (ulong)y); }
 #define DEF(type, m) OVERLOADABLE type rotate(type x, type y) { return __rotate_left(x, (type)(y & m)); }
 DEF(char, 7)