[AMDGPU] Pre-commit global-isel test case for D106451

This test case shows the scheduler wrongly reordering two buffer
accesses that might alias.

llvm/test/CodeGen/AMDGPU/GlobalISel/buffer-schedule.ll

@@ -0,0 +1,22 @@
+; RUN: llc -global-isel -mtriple=amdgcn-amd-amdpal -mcpu=gfx900 -verify-machineinstrs < %s | FileCheck -check-prefixes=GCN %s
+
+; FIXME: the first load and store should not be reordered because they might
+; alias depending on the value of %off
+; GCN-LABEL: {{^}}test1:
+; GCN: buffer_load_dword
+; GCN: buffer_store_dword
+; GCN: buffer_store_dword
+define amdgpu_cs void @test1(<4 x i32> inreg %buf, i32 %off) {
+.entry:
+  call void @llvm.amdgcn.raw.buffer.store.i32(i32 0, <4 x i32> %buf, i32 8, i32 0, i32 0)
+  %val = call i32 @llvm.amdgcn.raw.buffer.load.i32(<4 x i32> %buf, i32 %off, i32 0, i32 0)
+  call void @llvm.amdgcn.raw.buffer.store.i32(i32 %val, <4 x i32> %buf, i32 0, i32 0, i32 0)
+  ret void
+}
+
+declare i32 @llvm.amdgcn.raw.buffer.load.i32(<4 x i32>, i32, i32, i32) #2
+
+declare void @llvm.amdgcn.raw.buffer.store.i32(i32, <4 x i32>, i32, i32, i32) #3
+
+attributes #2 = { nounwind readonly }
+attributes #3 = { nounwind writeonly }