File: purecse.ll

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llvm-toolchain-20 1%3A20.1.6-1~exp1
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; Test that pure functions are cse'd away
; RUN: opt < %s -aa-pipeline=globals-aa,basic-aa -passes='require<globals-aa>,gvn,instcombine' -S | FileCheck %s

define i32 @pure(i32 %X) {
        %Y = add i32 %X, 1              ; <i32> [#uses=1]
        ret i32 %Y
}

define i32 @test1(i32 %X) {
; CHECK:      %A = call i32 @pure(i32 %X)
; CHECK-NEXT: ret i32 0
        %A = call i32 @pure( i32 %X )           ; <i32> [#uses=1]
        %B = call i32 @pure( i32 %X )           ; <i32> [#uses=1]
        %C = sub i32 %A, %B             ; <i32> [#uses=1]
        ret i32 %C
}

define i32 @test2(i32 %X, ptr %P) {
; CHECK:      %A = call i32 @pure(i32 %X)
; CHECK-NEXT: store i32 %X, ptr %P
; CHECK-NEXT: ret i32 0
        %A = call i32 @pure( i32 %X )           ; <i32> [#uses=1]
        store i32 %X, ptr %P ;; Does not invalidate 'pure' call.
        %B = call i32 @pure( i32 %X )           ; <i32> [#uses=1]
        %C = sub i32 %A, %B             ; <i32> [#uses=1]
        ret i32 %C
}