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; RUN: llc -mtriple=x86_64-apple-darwin -o - %s | FileCheck %s
; Simple case: completely identical returns, even with extensions, shouldn't be
; a barrier to tail calls.
declare zeroext i1 @give_bool()
define zeroext i1 @test_bool() {
; CHECK-LABEL: test_bool:
; CHECK: jmp
%call = tail call zeroext i1 @give_bool()
ret i1 %call
}
; Here, there's more zero extension to be done between the call and the return,
; so a tail call is impossible (well, according to current Clang practice
; anyway. The AMD64 ABI isn't crystal clear on the matter).
declare zeroext i32 @give_i32()
define zeroext i8 @test_i32() {
; CHECK-LABEL: test_i32:
; CHECK: callq _give_i32
; CHECK: movzbl %al, %eax
; CHECK: ret
%call = tail call zeroext i32 @give_i32()
%val = trunc i32 %call to i8
ret i8 %val
}
; Here, one function is zeroext and the other is signext. To the extent that
; these both mean something they are incompatible so no tail call is possible.
declare zeroext i16 @give_unsigned_i16()
define signext i16 @test_incompatible_i16() {
; CHECK-LABEL: test_incompatible_i16:
; CHECK: callq _give_unsigned_i16
; CHECK: cwtl
; CHECK: ret
%call = tail call zeroext i16 @give_unsigned_i16()
ret i16 %call
}
declare inreg i32 @give_i32_inreg()
define i32 @test_inreg_to_normal() {
; CHECK-LABEL: test_inreg_to_normal:
; CHECK: callq _give_i32_inreg
; CHECK: ret
%val = tail call inreg i32 @give_i32_inreg()
ret i32 %val
}
define inreg i32 @test_normal_to_inreg() {
; CHECK-LABEL: test_normal_to_inreg:
; CHECK: callq _give_i32
; CHECK: ret
%val = tail call i32 @give_i32()
ret i32 %val
}
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