Tail duplication still needs to iterate. Duplicating new instructions onto
the tail of a block may make that block a new candidate for duplication.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@89264 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/CodeGen/ARM/tail-opts.ll b/test/CodeGen/ARM/tail-opts.ll
new file mode 100644
index 0000000..c0651ba
--- /dev/null
+++ b/test/CodeGen/ARM/tail-opts.ll
@@ -0,0 +1,64 @@
+; RUN: llc < %s -march=arm -mcpu=cortex-a8 -asm-verbose=false | FileCheck %s
+
+declare void @bar(i32)
+declare void @car(i32)
+declare void @dar(i32)
+declare void @ear(i32)
+declare void @far(i32)
+declare i1 @qux()
+
+@GHJK = global i32 0
+
+declare i8* @choose(i8*, i8*);
+
+; BranchFolding should tail-duplicate the indirect jump to avoid
+; redundant branching.
+
+; CHECK: tail_duplicate_me:
+; CHECK: qux
+; CHECK: qux
+; CHECK: ldr r{{.}}, LCPI
+; CHECK: str r
+; CHECK-NEXT: bx r
+; CHECK: ldr r{{.}}, LCPI
+; CHECK: str r
+; CHECK-NEXT: bx r
+; CHECK: ldr r{{.}}, LCPI
+; CHECK: str r
+; CHECK-NEXT: bx r
+
+define void @tail_duplicate_me() nounwind {
+entry:
+ %a = call i1 @qux()
+ %c = call i8* @choose(i8* blockaddress(@tail_duplicate_me, %return),
+ i8* blockaddress(@tail_duplicate_me, %altret))
+ br i1 %a, label %A, label %next
+next:
+ %b = call i1 @qux()
+ br i1 %b, label %B, label %C
+
+A:
+ call void @bar(i32 0)
+ store i32 0, i32* @GHJK
+ br label %M
+
+B:
+ call void @car(i32 1)
+ store i32 0, i32* @GHJK
+ br label %M
+
+C:
+ call void @dar(i32 2)
+ store i32 0, i32* @GHJK
+ br label %M
+
+M:
+ indirectbr i8* %c, [label %return, label %altret]
+
+return:
+ call void @ear(i32 1000)
+ ret void
+altret:
+ call void @far(i32 1001)
+ ret void
+}