llvm-project/llvm/test/Analysis/GlobalsModRef/purecse.ll

28 lines
942 B
LLVM

; Test that pure functions are cse'd away
; RUN: opt < %s -globalsmodref-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, i32* %P) {
; CHECK: %A = call i32 @pure(i32 %X)
; CHECK-NEXT: store i32 %X, i32* %P
; CHECK-NEXT: ret i32 0
%A = call i32 @pure( i32 %X ) ; <i32> [#uses=1]
store i32 %X, i32* %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
}