[Autobackout][FuncReg]Revert of change: 07409ae

Flush L3 for device or cross-device memory fence on global memory.

Change-Id: Ibefed5c1e1b5b5b327779224f3f7b2ab91fdd4f9

Author: weiyu-chen

IGC/BiFModule/Implementation/atomics.cl

@@ -54,15 +54,13 @@ SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 #define FENCE_PRE_OP(Scope, Semantics, isGlobal)                                  \
   if( ( (Semantics) & ( SEMANTICS_PRE_OP_NEED_FENCE ) ) > 0 )                     \
   {                                                                               \
-      bool flushL3 = (isGlobal) && ((Scope) == Device || (Scope) == CrossDevice); \
-      __builtin_IB_memfence(true, flushL3, false, false, false, isGlobal, false); \
+      __builtin_IB_memfence(true, false, false, false, false, isGlobal, false);   \
   }
 
 #define FENCE_POST_OP(Scope, Semantics, isGlobal)                                 \
   if( ( (Semantics) & ( SEMANTICS_POST_OP_NEEDS_FENCE ) ) > 0 )                   \
   {                                                                               \
-      bool flushL3 = (isGlobal) && ((Scope) == Device || (Scope) == CrossDevice); \
-      __builtin_IB_memfence(true, flushL3, false, false, false, isGlobal, false); \
+      __builtin_IB_memfence(true, false, false, false, false, isGlobal, false);   \
   }
 
 // This fencing scheme allows us to obey the memory model when coherency is

IGC/BiFModule/Implementation/barrier.cl

@@ -47,11 +47,11 @@ static void __intel_atomic_work_item_fence( Scope_t Memory, uint Semantics )
         }
         else if( Semantics & ( CrossWorkgroupMemory | WorkgroupMemory ) )
         {
-            // A global/local opencl fence requires a hardware fence
+            // A global/local opencl fence requires a hardware fence,
+            // but no L3 flush needed.
             // We let the code generation decide whether we can elide local fences or not,
             // so we need to pass the CLK_GLOBAL flag forward
-            bool flushL3 = Memory == Device || Memory == CrossDevice;
-            __builtin_IB_memfence(true, flushL3, false, false, false, Semantics & CrossWorkgroupMemory, invalidateL1);
+            __builtin_IB_memfence(true, false, false, false, false, Semantics & CrossWorkgroupMemory, invalidateL1);
         }
     }
 }

IGC/Compiler/CISACodeGen/EmitVISAPass.cpp

@@ -13445,11 +13445,6 @@ void EmitPass::emitMemoryFence(llvm::Instruction* inst)
     bool L3_Flush_Instructions = llvm::cast<llvm::ConstantInt>((inst->getOperand(4)))->getValue().getBoolValue();
     bool Global_Mem_Fence = true;
     bool L1_Invalidate = llvm::cast<llvm::ConstantInt>((inst->getOperand(6)))->getValue().getBoolValue() && ctx->platform.hasL1ReadOnlyCache();
-    if (L3_Flush_RW_Data)
-    {
-        // dont flush L1 if L3 is also being flushed
-        L1_Invalidate = false;
-    }
 
     bool EmitFence = true;
     // If passed a non-constant parameter, be conservative and emit a fence.