1; RUN: llc -mtriple=x86_64-apple-darwin -o - %s | FileCheck %s 2 3; Simple case: completely identical returns, even with extensions, shouldn't be 4; a barrier to tail calls. 5declare zeroext i1 @give_bool() 6define zeroext i1 @test_bool() { 7; CHECK-LABEL: test_bool: 8; CHECK: jmp 9 %call = tail call zeroext i1 @give_bool() 10 ret i1 %call 11} 12 13; Here, there's more zero extension to be done between the call and the return, 14; so a tail call is impossible (well, according to current Clang practice 15; anyway. The AMD64 ABI isn't crystal clear on the matter). 16; FIXME: The high 24 bits returned from test_i32 are undefined; do tail call! 17declare zeroext i32 @give_i32() 18define zeroext i8 @test_i32() { 19; CHECK-LABEL: test_i32: 20; CHECK: callq _give_i32 21; CHECK: ret 22 23 %call = tail call zeroext i32 @give_i32() 24 %val = trunc i32 %call to i8 25 ret i8 %val 26} 27 28; Here, one function is zeroext and the other is signext. To the extent that 29; these both mean something they are incompatible so no tail call is possible. 30; FIXME: The high 16 bits returned are undefined; do tail call! 31declare zeroext i16 @give_unsigned_i16() 32define signext i16 @test_incompatible_i16() { 33; CHECK-LABEL: test_incompatible_i16: 34; CHECK: callq _give_unsigned_i16 35; CHECK: ret 36 37 %call = tail call zeroext i16 @give_unsigned_i16() 38 ret i16 %call 39} 40 41declare inreg i32 @give_i32_inreg() 42define i32 @test_inreg_to_normal() { 43; CHECK-LABEL: test_inreg_to_normal: 44; CHECK: callq _give_i32_inreg 45; CHECK: ret 46 %val = tail call inreg i32 @give_i32_inreg() 47 ret i32 %val 48} 49 50define inreg i32 @test_normal_to_inreg() { 51; CHECK-LABEL: test_normal_to_inreg: 52; CHECK: callq _give_i32 53; CHECK: ret 54 %val = tail call i32 @give_i32() 55 ret i32 %val 56} 57