Revert "Set 128 grf size by default"

.

Author: AnBodrova

IGC/VectorCompiler/lib/GenXCodeGen/GenXCisaBuilder.cpp

@@ -949,8 +949,7 @@ static void addKernelAttrsFromMetadata(VISAKernel &Kernel,
     Kernel.AddKernelAttribute("NBarrierCnt", sizeof(BarrierCnt), &BarrierCnt);
   }
 
-  // Default number of registers.
-  unsigned NumGRF = 128;
+  int NumGRF = -1;
   // Set by compile option.
   if (BC->isAutoLargeGRFMode())
     NumGRF = 0;
@@ -962,7 +961,9 @@ static void addKernelAttrsFromMetadata(VISAKernel &Kernel,
     if (NumGRFPerKernel == 0 || Subtarget->isValidGRFSize(NumGRFPerKernel))
       NumGRF = NumGRFPerKernel;
   }
-  Kernel.AddKernelAttribute("NumGRF", sizeof(NumGRF), &NumGRF);
+
+  if (NumGRF != -1)
+    Kernel.AddKernelAttribute("NumGRF", sizeof(NumGRF), &NumGRF);
 }
 
 // Legalize name for using as filename or in visa asm

IGC/VectorCompiler/test/CisaBuilder/grf_size.ll

@@ -27,12 +27,12 @@ define dllexport spir_kernel void @test_auto(i32 %arg) #0 {
   ret void
 }
 
-; CHECK: .kernel_attr NumGRF=128
+; CHECK-NOT: .kernel_attr NumGRF
 define dllexport spir_kernel void @test_default(i32 %arg) #0 {
   ret void
 }
 
-; CHECK: .kernel_attr NumGRF=128
+; CHECK-NOT: .kernel_attr NumGRF
 define dllexport spir_kernel void @test_invalid(i32 %arg) #0 {
   ret void
 }