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. 5 declare zeroext i1 @give_bool() 6 define 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 declare zeroext i32 @give_i32() 17 define zeroext i8 @test_i32() { 18 ; CHECK-LABEL: test_i32: 19 ; CHECK: callq _give_i32 20 ; CHECK: movzbl %al, %eax 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 declare zeroext i16 @give_unsigned_i16() 31 define signext i16 @test_incompatible_i16() { 32 ; CHECK-LABEL: test_incompatible_i16: 33 ; CHECK: callq _give_unsigned_i16 34 ; CHECK: cwtl 35 ; CHECK: ret 36 37 %call = tail call zeroext i16 @give_unsigned_i16() 38 ret i16 %call 39 } 40 41 declare inreg i32 @give_i32_inreg() 42 define 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 50 define 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
