--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/CodeGen/Mips/cconv/reserved-space.ll	Mon Sep 08 22:06:00 2014 +0900
@@ -0,0 +1,39 @@
+; RUN: llc -march=mips < %s | FileCheck --check-prefix=ALL --check-prefix=O32 %s
+; RUN: llc -march=mipsel < %s | FileCheck --check-prefix=ALL --check-prefix=O32 %s
+
+; RUN-TODO: llc -march=mips64 -mattr=-n64,+o32 < %s | FileCheck --check-prefix=ALL --check-prefix=O32 %s
+; RUN-TODO: llc -march=mips64el -mattr=-n64,+o32 < %s | FileCheck --check-prefix=ALL --check-prefix=O32 %s
+
+; RUN: llc -march=mips64 -mattr=-n64,+n32 < %s | FileCheck --check-prefix=ALL --check-prefix=N32 %s
+; RUN: llc -march=mips64el -mattr=-n64,+n32 < %s | FileCheck --check-prefix=ALL --check-prefix=N32 %s
+
+; RUN: llc -march=mips64 -mattr=-n64,+n64 < %s | FileCheck --check-prefix=ALL --check-prefix=N64 %s
+; RUN: llc -march=mips64el -mattr=-n64,+n64 < %s | FileCheck --check-prefix=ALL --check-prefix=N64 %s
+
+; Test that O32 correctly reserved space for the four arguments, even when
+; there aren't any as per section 5 of MD00305 (MIPS ABIs Described).
+
+declare void @foo() nounwind;
+
+define void @reserved_space() nounwind {
+entry:
+        tail call void @foo()
+        ret void
+}
+
+; ALL-LABEL: reserved_space:
+; O32:           addiu $sp, $sp, -24
+; O32:           sw $ra, 20($sp)
+; O32:           lw $ra, 20($sp)
+; O32:           addiu $sp, $sp, 24
+; Despite pointers being 32-bit wide on N32, the return pointer is saved as a
+; 64-bit pointer. I've yet to find a documentation reference for this quirk but
+; this behaviour matches GCC so I have considered it to be correct.
+; N32:           addiu $sp, $sp, -16
+; N32:           sd $ra, 8($sp)
+; N32:           ld $ra, 8($sp)
+; N32:           addiu $sp, $sp, 16
+; N64:           daddiu $sp, $sp, -16
+; N64:           sd $ra, 8($sp)
+; N64:           ld $ra, 8($sp)
+; N64:           daddiu $sp, $sp, 16