R600/SI: Add some mubuf testcases.

[arsenm]

Summary

I noticed some odd looking cases where addr64 wasn't set
when storing to a pointer in an SGPR. This seems to be intentional,
and partially tested already.

The documentation seems to describe addr64 in terms of which registers
addressing modifiers come from, but I would expect to always need
addr64 when using 64-bit pointers. If no offset is applied,
it makes sense to not need to worry about doing a 64-bit add
for the final address. A small immediate offset can be applied,
so is it OK to not have addr64 set if a carry is necessary when adding
the base pointer in the resource to the offset?

[arsenm]

r217785

test/CodeGen/R600/mubuf.ll

 ; RUN: llc -march=r600 -mcpu=SI -show-mc-encoding -verify-machineinstrs < %s | FileCheck %s
 
+declare i32 @llvm.r600.read.tidig.x() readnone
+
 ;;;==========================================================================;;;
 ;;; MUBUF LOAD TESTS
 ;;;==========================================================================;;;

   store i32 0, i32 addrspace(1)* %1
   ret void
 }
+
+; CHECK-LABEL: @store_sgpr_ptr
+; CHECK: BUFFER_STORE_DWORD v{{[0-9]+}}, s{{\[[0-9]+:[0-9]+\]}}, 0
+define void @store_sgpr_ptr(i32 addrspace(1)* %out) #0 {
+  store i32 99, i32 addrspace(1)* %out, align 4
+  ret void
+}
+
+; CHECK-LABEL: @store_sgpr_ptr_offset
+; CHECK: BUFFER_STORE_DWORD v{{[0-9]+}}, s{{\[[0-9]+:[0-9]+\]}}, 0 offset:0x28
+define void @store_sgpr_ptr_offset(i32 addrspace(1)* %out) #0 {
+  %out.gep = getelementptr i32 addrspace(1)* %out, i32 10
+  store i32 99, i32 addrspace(1)* %out.gep, align 4
+  ret void
+}
+
+; CHECK-LABEL: @store_sgpr_ptr_large_offset
+; CHECK: BUFFER_STORE_DWORD v{{[0-9]+}}, v{{\[[0-9]+:[0-9]+\]}}, s{{\[[0-9]+:[0-9]+\]}}, 0 addr64
+define void @store_sgpr_ptr_large_offset(i32 addrspace(1)* %out) #0 {
+  %out.gep = getelementptr i32 addrspace(1)* %out, i32 32768
+  store i32 99, i32 addrspace(1)* %out.gep, align 4
+  ret void
+}
+
+; CHECK-LABEL: @store_vgpr_ptr
+; CHECK: BUFFER_STORE_DWORD v{{[0-9]+}}, v{{\[[0-9]+:[0-9]+\]}}, s{{\[[0-9]+:[0-9]+\]}}, 0 addr64
+define void @store_vgpr_ptr(i32 addrspace(1)* %out) #0 {
+  %tid = call i32 @llvm.r600.read.tidig.x() readnone
+  %out.gep = getelementptr i32 addrspace(1)* %out, i32 %tid
+  store i32 99, i32 addrspace(1)* %out.gep, align 4
+  ret void
+}