In order to correctly compile

struct s {
  double x1;
  float x2;
};
__attribute__((regparm(3))) struct s f(int a, int b, int c);
void g(void) {
  f(41, 42, 43);
}

We need to be able to represent passing the address of s to f (sret) in a
register (inreg). Turns out that all that is needed is to not mark them as
mutually incompatible.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160695 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/CodeGen/X86/inreg.ll b/test/CodeGen/X86/inreg.ll
new file mode 100644
index 0000000..8981033
--- /dev/null
+++ b/test/CodeGen/X86/inreg.ll
@@ -0,0 +1,19 @@
+; RUN: llc < %s -march=x86 | FileCheck %s
+
+%struct.s = type { double, float }
+
+define void @g() nounwind {
+entry:
+  %tmp = alloca %struct.s, align 4
+  call void @f(%struct.s* inreg sret %tmp, i32 inreg 41, i32 inreg 42, i32 43)
+  ret void
+  ; CHECK: g:
+  ; CHECK: subl {{.*}}, %esp
+  ; CHECK-NEXT: $43, (%esp)
+  ; CHECK-NEXT: leal    16(%esp), %eax
+  ; CHECK-NEXT: movl    $41, %edx
+  ; CHECK-NEXT: movl    $42, %ecx
+  ; CHECK-NEXT: calll   f
+}
+
+declare void @f(%struct.s* inreg sret, i32 inreg, i32 inreg, i32)