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; RUN: opt < %s -ipsccp -S | FileCheck %s
; PR36485
; musttail call result can\'t be replaced with a constant, unless the call
; can be removed
declare i32 @external()
define i8* @start(i8 %v) {
%c1 = icmp eq i8 %v, 0
br i1 %c1, label %true, label %false
true:
; CHECK: %ca = musttail call i8* @side_effects(i8 0)
; CHECK: ret i8* %ca
%ca = musttail call i8* @side_effects(i8 %v)
ret i8* %ca
false:
%c2 = icmp eq i8 %v, 1
br i1 %c2, label %c2_true, label %c2_false
c2_true:
%ca1 = musttail call i8* @no_side_effects(i8 %v)
; CHECK: ret i8* null
ret i8* %ca1
c2_false:
; CHECK: %ca2 = musttail call i8* @dont_zap_me(i8 %v)
; CHECK: ret i8* %ca2
%ca2 = musttail call i8* @dont_zap_me(i8 %v)
ret i8* %ca2
}
define internal i8* @side_effects(i8 %v) {
%i1 = call i32 @external()
; since this goes back to `start` the SCPP should be see that the return value
; is always `null`.
; The call can't be removed due to `external` call above, though.
; CHECK: %ca = musttail call i8* @start(i8 0)
%ca = musttail call i8* @start(i8 %v)
; Thus the result must be returned anyway
; CHECK: ret i8* %ca
ret i8* %ca
}
define internal i8* @no_side_effects(i8 %v) readonly nounwind {
; The call to this function is removed, so the return value must be zapped
; CHECK: ret i8* undef
ret i8* null
}
define internal i8* @dont_zap_me(i8 %v) {
%i1 = call i32 @external()
; The call to this function cannot be removed due to side effects. Thus the
; return value should stay as it is, and should not be zapped.
; CHECK: ret i8* null
ret i8* null
}
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