1 files changed, 23 insertions, 0 deletions
diff --git a/test/CodeGen/X86/remat-phys-dead.ll b/test/CodeGen/X86/remat-phys-dead.ll
new file mode 100644
index 0000000000000..4d7ee622a37e0
--- /dev/null
+++ b/test/CodeGen/X86/remat-phys-dead.ll
@@ -0,0 +1,23 @@
+; REQUIRES: asserts
+; RUN: llc -mtriple=x86_64-apple-darwin -debug -o /dev/null < %s 2>&1 | FileCheck %s
+
+; We need to make sure that rematerialization into a physical register marks the
+; super- or sub-register as dead after this rematerialization since only the
+; original register is actually used later. Largely irrelevant for a trivial
+; example like this, since EAX is never used again, but easy to test.
+
+define i8 @test_remat() {
+  ret i8 0
+; CHECK: REGISTER COALESCING
+; CHECK: Remat: %EAX<def,dead> = MOV32r0 %EFLAGS<imp-def,dead>, %AL<imp-def>
+}
+
+; On the other hand, if it's already the correct width, we really shouldn't be
+; marking the definition register as dead.
+
+define i32 @test_remat32() {
+  ret i32 0
+; CHECK: REGISTER COALESCING
+; CHECK: Remat: %EAX<def> = MOV32r0 %EFLAGS<imp-def,dead>
+}
+