GBE: Fix fast-math issue under llvm 3.6.

"__ocl_math_fastpath_flag" was directly optimized out when compiling libocl under llvm 3.6
And set its initialization value after loading libocl.

Signed-off-by: Ruiling Song <ruiling.song@intel.com>
Reviewed-by: Zhigang Gong <zhigang.gong@linux.intel.com>

2 files changed, 5 insertions, 7 deletions

diff --git a/backend/src/libocl/tmpl/ocl_math.tmpl.cl b/backend/src/libocl/tmpl/ocl_math.tmpl.cl
index 49c4efa5..fcc60fd7 100644
--- a/backend/src/libocl/tmpl/ocl_math.tmpl.cl
+++ b/backend/src/libocl/tmpl/ocl_math.tmpl.cl
@@ -21,7 +21,7 @@
 #include "ocl_common.h"
 #include "ocl_integer.h"
 
-constant int __ocl_math_fastpath_flag = 1;
+extern constant int __ocl_math_fastpath_flag;
 
 PURE CONST float __gen_ocl_fabs(float x);
 PURE CONST float __gen_ocl_sin(float x);
diff --git a/backend/src/llvm/llvm_bitcode_link.cpp b/backend/src/llvm/llvm_bitcode_link.cpp
index 61e2ea15..96f77810 100644
--- a/backend/src/llvm/llvm_bitcode_link.cpp
+++ b/backend/src/llvm/llvm_bitcode_link.cpp
@@ -73,12 +73,10 @@ namespace gbe
       return NULL;
     }
 
-    if (strictMath) {
-      llvm::GlobalVariable* mathFastFlag = oclLib->getGlobalVariable("__ocl_math_fastpath_flag");
-      assert(mathFastFlag);
-      Type* intTy = IntegerType::get(ctx, 32);
-      mathFastFlag->setInitializer(ConstantInt::get(intTy, 0));
-    }
+    llvm::GlobalVariable* mathFastFlag = oclLib->getGlobalVariable("__ocl_math_fastpath_flag");
+    assert(mathFastFlag);
+    Type* intTy = IntegerType::get(ctx, 32);
+    mathFastFlag->setInitializer(ConstantInt::get(intTy, strictMath ? 0 : 1));
 
     return oclLib;
   }