Reapply "R600: Add new intrinsic to read work dimensions"

This effectively reverts revert 219707. After fixing the test to work with
new function name format and renamed intrinsic.

Reviewed-by: Tom Stellard <tom@stellard.net>
Signed-off-by: Jan Vesely <jan.vesely@rutgers.edu>
llvm-svn: 219710
diff --git a/llvm/lib/Target/R600/AMDGPUMachineFunction.h b/llvm/lib/Target/R600/AMDGPUMachineFunction.h
index 886fb1b..f5e4694 100644
--- a/llvm/lib/Target/R600/AMDGPUMachineFunction.h
+++ b/llvm/lib/Target/R600/AMDGPUMachineFunction.h
@@ -30,6 +30,9 @@
   /// Number of bytes in the LDS that are being used.
   unsigned LDSSize;
 
+  /// Start of implicit kernel args
+  unsigned ABIArgOffset;
+
   unsigned getShaderType() const {
     return ShaderType;
   }