AMDGPU: Add a shader calling convention

This makes it possible to distinguish between mesa shaders
and other kernels even in the presence of compute shaders.

Patch By: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>

Differential Revision: http://reviews.llvm.org/D18559

llvm-svn: 265589
diff --git a/llvm/test/CodeGen/AMDGPU/pv-packing.ll b/llvm/test/CodeGen/AMDGPU/pv-packing.ll
index abeae56..75091c4 100644
--- a/llvm/test/CodeGen/AMDGPU/pv-packing.ll
+++ b/llvm/test/CodeGen/AMDGPU/pv-packing.ll
@@ -3,7 +3,7 @@
 ;CHECK: DOT4  T{{[0-9]\.X}}
 ;CHECK: MULADD_IEEE * T{{[0-9]\.W}}
 
-define void @main(<4 x float> inreg %reg0, <4 x float> inreg %reg1, <4 x float> inreg %reg2, <4 x float> inreg %reg3) #0 {
+define amdgpu_vs void @main(<4 x float> inreg %reg0, <4 x float> inreg %reg1, <4 x float> inreg %reg2, <4 x float> inreg %reg3) {
 main_body:
   %0 = extractelement <4 x float> %reg1, i32 0
   %1 = extractelement <4 x float> %reg1, i32 1
@@ -41,5 +41,4 @@
 
 declare void @llvm.R600.store.swizzle(<4 x float>, i32, i32)
 
-attributes #0 = { "ShaderType"="1" }
 attributes #1 = { readnone }