enable FP_CONTRACT on as default, and implemented with MAD

According to OpenCL spec, FP_CONTRACT is on as default, while LLVM/clang
just enabled it at http://reviews.llvm.org/D14200 at Nov 2015. So we still
need set this option explicitly now.

The implementation is hardware MAD instruction whose accuracy is enough
for FP_CONTRACT.

Passed test:  contractions of conformance test

Signed-off-by: Guo Yejun <yejun.guo@intel.com>
Reviewed-by: Ruiling Song <ruiling.song@intel.com>

3 files changed, 3 insertions, 12 deletions

diff --git a/backend/src/backend/program.cpp b/backend/src/backend/program.cpp
index 2c233ea5..5eee4cbd 100644
--- a/backend/src/backend/program.cpp
+++ b/backend/src/backend/program.cpp
@@ -630,7 +630,7 @@ namespace gbe {
     args.push_back("spir");
 #endif /* LLVM_VERSION_MINOR <= 2 */
     args.push_back("stringInput.cl");
-    args.push_back("-ffp-contract=off");
+    args.push_back("-ffp-contract=on");
     if(OCL_DEBUGINFO) args.push_back("-g");
 
     // The compiler invocation needs a DiagnosticsEngine so it can report problems
diff --git a/backend/src/llvm/llvm_gen_backend.cpp b/backend/src/llvm/llvm_gen_backend.cpp
index bbbd5378..f43f8702 100644
--- a/backend/src/llvm/llvm_gen_backend.cpp
+++ b/backend/src/llvm/llvm_gen_backend.cpp
@@ -3926,17 +3926,6 @@ namespace gbe
           }
           break;
 #if LLVM_VERSION_MINOR >= 2
-          case Intrinsic::fmuladd:
-          {
-            const ir::Register tmp  = ctx.reg(ir::FAMILY_DWORD);
-            const ir::Register dst  = this->getRegister(&I);
-            const ir::Register src0 = this->getRegister(I.getOperand(0));
-            const ir::Register src1 = this->getRegister(I.getOperand(1));
-            const ir::Register src2 = this->getRegister(I.getOperand(2));
-            ctx.MUL(ir::TYPE_FLOAT, tmp, src0, src1);
-            ctx.ADD(ir::TYPE_FLOAT, dst, tmp, src2);
-          }
-          break;
           case Intrinsic::lifetime_start:
           case Intrinsic::lifetime_end:
           break;
@@ -4023,6 +4012,7 @@ namespace gbe
           }
           break;
           case Intrinsic::fma:
+          case Intrinsic::fmuladd:
           {
             ir::Type srcType = getType(ctx, I.getType());
             const ir::Register dst = this->getRegister(&I);
diff --git a/backend/src/llvm/llvm_scalarize.cpp b/backend/src/llvm/llvm_scalarize.cpp
index 9efb8975..414bbac9 100644
--- a/backend/src/llvm/llvm_scalarize.cpp
+++ b/backend/src/llvm/llvm_scalarize.cpp
@@ -269,6 +269,7 @@ namespace gbe {
           case Intrinsic::sqrt:
           case Intrinsic::ceil:
           case Intrinsic::trunc:
+          case Intrinsic::fmuladd:
               return true;
         }
     }