Change swift/vldm test case to be less dependent on allocation order

'Force' values in registers using the calling convention. Now, we only depend on
the calling convention and that the allocator performs copy coalescing.

llvm-svn: 189985

llvm/test/CodeGen/ARM/swift-vldm.ll

@@ -4,25 +4,25 @@
 ; so that there usage becomes unbeneficial on swift.
 
 ; CHECK-LABEL: test_vldm
-; CHECK: vldmia  r1, {d18, d19, d20}
-; CHECK-NOT: vldmia  r1, {d17, d18, d19, d20}
+; CHECK: vldmia r{{[0-9]+}}, {d2, d3, d4}
+; CHECK-NOT: vldmia r{{[0-9]+}}, {d1, d2, d3, d4}
 
-define double @test_vldm(double %a, double %b, double* nocapture %x) {
+declare fastcc void @force_register(double %d0, double %d1, double %d2, double %d3, double %d4) 
+
+define void @test_vldm(double* %x, double * %y) {
 entry:
-  %mul73 = fmul double %a, %b
   %addr1 = getelementptr double * %x, i32 1
   %addr2 = getelementptr double * %x, i32 2
   %addr3 = getelementptr double * %x, i32 3
-  %load0 = load double * %x
-  %load1 = load double * %addr1
-  %load2 = load double * %addr2
-  %load3 = load double * %addr3
-  %sub = fsub double %mul73, %load1
-  %mul = fmul double %mul73, %load0
-  %add = fadd double %mul73, %load2
-  %div = fdiv double %mul73, %load3
-  %red = fadd double %sub, %mul
-  %red2 = fadd double %div, %add
-  %red3 = fsub double %red, %red2
-  ret double %red3
+  %d0 = load double * %y
+  %d1 = load double * %x
+  %d2 = load double * %addr1
+  %d3 = load double * %addr2
+  %d4 = load double * %addr3
+  ; We are trying to force x[0-3] in register d1 to d4 so that we can test we
+  ; don't form a "vldmia rX, {d1, d2, d3, d4}".
+  ; We are relying on the calling convention and that register allocation
+  ; properly coalesces registers.
+  call fastcc void @force_register(double %d0, double %d1, double %d2, double %d3, double %d4)
+  ret void
 }