[NFC] [DirectX] Make DirectX codegen test CBufferAccess/gep-ce-two-uses.ll more strict (llvm#169855)

Continuation of PR llvm#169848 to address PR comments.

This PR makes the test more strict by adding CHECKs to ensure the loads
are indeed using the same or different GEPs.

Author: Icohedron

llvm/test/CodeGen/DirectX/CBufferAccess/gep-ce-two-uses.ll

@@ -17,7 +17,8 @@
 define void @f(ptr %dst) {
 entry:
   ; CHECK: [[PTR:%.*]] = call ptr addrspace(2) @llvm.dx.resource.getpointer.{{.*}}(target("dx.CBuffer", %__cblayout_CB) {{%.*}}, i32 0)
-  ; CHECK: getelementptr inbounds nuw i8, ptr addrspace(2) [[PTR]], i32 16
+  ; CHECK: [[GEP:%.*]] = getelementptr inbounds nuw i8, ptr addrspace(2) [[PTR]], i32 16
+  ; CHECK-COUNT-2: load float, ptr addrspace(2) [[GEP]]
   %a1 = load float, ptr addrspace(2) getelementptr inbounds nuw (i8, ptr addrspace(2) @a1, i32 16), align 4
   store float %a1, ptr %dst, align 32
 
@@ -30,15 +31,17 @@ entry:
 ; CHECK: define void @g
 define void @g(ptr %dst) {
 entry:
-  ; CHECK: [[PTR:%.*]] = call ptr addrspace(2) @llvm.dx.resource.getpointer.{{.*}}(target("dx.CBuffer", %__cblayout_CB) {{%.*}}, i32 0)
-  ; CHECK: getelementptr inbounds nuw i8, ptr addrspace(2) [[PTR]], i32 16
+  ; CHECK: [[PTR1:%.*]] = call ptr addrspace(2) @llvm.dx.resource.getpointer.{{.*}}(target("dx.CBuffer", %__cblayout_CB) {{%.*}}, i32 0)
+  ; CHECK: [[GEP1:%.*]] = getelementptr inbounds nuw i8, ptr addrspace(2) [[PTR1]], i32 16
+  ; CHECK: load float, ptr addrspace(2) [[GEP1]]
   %a1 = load float, ptr addrspace(2) getelementptr inbounds nuw (i8, ptr addrspace(2) @a1, i32 16), align 4
   store float %a1, ptr %dst, align 32
   br label %next
 
 next:
-  ; CHECK: [[PTR:%.*]] = call ptr addrspace(2) @llvm.dx.resource.getpointer.{{.*}}(target("dx.CBuffer", %__cblayout_CB) {{%.*}}, i32 0)
-  ; CHECK: getelementptr inbounds nuw i8, ptr addrspace(2) [[PTR]], i32 16
+  ; CHECK: [[PTR2:%.*]] = call ptr addrspace(2) @llvm.dx.resource.getpointer.{{.*}}(target("dx.CBuffer", %__cblayout_CB) {{%.*}}, i32 0)
+  ; CHECK: [[GEP2:%.*]] = getelementptr inbounds nuw i8, ptr addrspace(2) [[PTR2]], i32 16
+  ; CHECK: load float, ptr addrspace(2) [[GEP2]]
   %a2 = load float, ptr addrspace(2) getelementptr inbounds nuw (i8, ptr addrspace(2) @a1, i32 16), align 4
   store float %a2, ptr %dst, align 32