DirectXShaderCompiler/test/Transforms/TailCallElim/dup_tail.ll

; REQUIRES: asserts
; Duplicate the return into if.end to enable TCE.
; RUN: opt -tailcallelim -stats -disable-output < %s 2>&1 | FileCheck %s

; CHECK: Number of return duplicated

define i32 @fib(i32 %n) nounwind ssp {
entry:
  %cmp = icmp slt i32 %n, 2
  br i1 %cmp, label %if.then, label %if.end

if.then:                                          ; preds = %entry
  br label %return

if.end:                                           ; preds = %entry
  %sub = add nsw i32 %n, -2
  %call = call i32 @fib(i32 %sub)
  %sub3 = add nsw i32 %n, -1
  %call4 = call i32 @fib(i32 %sub3)
  %add = add nsw i32 %call, %call4
  br label %return

return:                                           ; preds = %if.end, %if.then
  %retval.0 = phi i32 [ 1, %if.then ], [ %add, %if.end ]
  ret i32 %retval.0
}