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/input-mods.ll b/llvm/test/CodeGen/AMDGPU/input-mods.ll
index 1c4d285..c098d23 100644
--- a/llvm/test/CodeGen/AMDGPU/input-mods.ll
+++ b/llvm/test/CodeGen/AMDGPU/input-mods.ll
@@ -9,7 +9,7 @@
 ;CM: EXP_IEEE T{{[0-9]+}}.Z (MASKED), -|T{{[0-9]+}}.X|
 ;CM: EXP_IEEE * T{{[0-9]+}}.W (MASKED), -|T{{[0-9]+}}.X|
 
-define void @test(<4 x float> inreg %reg0) #0 {
+define amdgpu_ps void @test(<4 x float> inreg %reg0) {
    %r0 = extractelement <4 x float> %reg0, i32 0
    %r1 = call float @llvm.fabs.f32(float %r0)
    %r2 = fsub float -0.000000e+00, %r1
@@ -22,5 +22,3 @@
 declare float @llvm.exp2.f32(float) readnone
 declare float @llvm.fabs.f32(float) readnone
 declare void @llvm.R600.store.swizzle(<4 x float>, i32, i32)
-
-attributes #0 = { "ShaderType"="0" }