1 files changed, 53 insertions, 0 deletions
diff --git a/llvm/test/CodeGen/X86/tail-dup-repeat.ll b/llvm/test/CodeGen/X86/tail-dup-repeat.ll
new file mode 100644
index 00000000000..21b48e16efb
--- /dev/null
+++ b/llvm/test/CodeGen/X86/tail-dup-repeat.ll
@@ -0,0 +1,53 @@
+; RUN: llc -O2 -tail-dup-placement-threshold=4 -o - %s | FileCheck %s
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+; Function Attrs: uwtable
+; When tail-duplicating during placement, we work backward from blocks with
+; multiple successors. In this case, the block dup1 gets duplicated into dup2
+; and if.then64, and then the block dup2 gets duplicated into land.lhs.true
+; and if.end70
+; CHECK-LABEL: repeated_tail_dup:
+define void @repeated_tail_dup(i1 %a1, i1 %a2, i32* %a4, i32* %a5, i8* %a6) #0 align 2 {
+entry:
+  br label %for.cond
+
+; CHECK: {{^}}.[[HEADER:LBB0_[1-9]]]: # %for.cond
+for.cond:                                         ; preds = %dup1, %entry
+  br i1 %a1, label %land.lhs.true, label %if.end56
+
+land.lhs.true:                                    ; preds = %for.cond
+  store i32 10, i32* %a4, align 8
+  br label %dup2
+
+if.end56:                                         ; preds = %for.cond
+  br i1 %a2, label %if.then64, label %if.end70
+
+if.then64:                                        ; preds = %if.end56
+  store i8 1, i8* %a6, align 1
+  br label %dup1
+
+; CHECK:      # %if.end70
+; CHECK-NEXT: # in Loop:
+; CHECK-NEXT: movl $12, (%rdx)
+; CHECK-NEXT: movl $2, (%rcx)
+; CHECK-NEXT: testl %eax, %eax
+; CHECK-NEXT: je .[[HEADER]]
+if.end70:                                         ; preds = %if.end56
+  store i32 12, i32* %a4, align 8
+  br label %dup2
+
+dup2:                                             ; preds = %if.end70, %land.lhs.true
+  store i32 2, i32* %a5, align 4
+  br label %dup1
+
+dup1:                                             ; preds = %dup2, %if.then64
+  %val = load i32, i32* %a4, align 8
+  %switch = icmp ult i32 undef, 1
+  br i1 %switch, label %for.cond, label %for.end
+
+for.end:                                          ; preds = %dup1
+  ret void
+}
+
+attributes #0 = { uwtable }