1 files changed, 56 insertions, 0 deletions
diff --git a/test/CodeGen/X86/use-add-flags.ll b/test/CodeGen/X86/use-add-flags.ll
new file mode 100644
index 0000000..8252030
--- /dev/null
+++ b/test/CodeGen/X86/use-add-flags.ll
@@ -0,0 +1,56 @@
+; RUN: llc < %s -march=x86-64 -o - | FileCheck %s
+
+; Reuse the flags value from the add instructions instead of emitting separate
+; testl instructions.
+
+; Use the flags on the add.
+
+; CHECK: add_zf:
+;      CHECK: addl    (%rdi), %esi
+; CHECK-NEXT: movl    %edx, %eax
+; CHECK-NEXT: cmovnsl %ecx, %eax
+; CHECK-NEXT: ret
+
+define i32 @add_zf(i32* %x, i32 %y, i32 %a, i32 %b) nounwind {
+	%tmp2 = load i32* %x, align 4		; <i32> [#uses=1]
+	%tmp4 = add i32 %tmp2, %y		; <i32> [#uses=1]
+	%tmp5 = icmp slt i32 %tmp4, 0		; <i1> [#uses=1]
+	%tmp.0 = select i1 %tmp5, i32 %a, i32 %b		; <i32> [#uses=1]
+	ret i32 %tmp.0
+}
+
+declare void @foo(i32)
+
+; Don't use the flags result of the and here, since the and has no
+; other use. A simple test is better.
+
+; CHECK: bar:
+; CHECK: testb   $16, %dil
+
+define void @bar(i32 %x) nounwind {
+  %y = and i32 %x, 16
+  %t = icmp eq i32 %y, 0
+  br i1 %t, label %true, label %false
+true:
+  call void @foo(i32 %x)
+  ret void
+false:
+  ret void
+}
+
+; Do use the flags result of the and here, since the and has another use.
+
+; CHECK: qux:
+;      CHECK: andl    $16, %edi
+; CHECK-NEXT: jne     .LBB3_2
+
+define void @qux(i32 %x) nounwind {
+  %y = and i32 %x, 16
+  %t = icmp eq i32 %y, 0
+  br i1 %t, label %true, label %false
+true:
+  call void @foo(i32 %y)
+  ret void
+false:
+  ret void
+}