Leslie Zhai via llvm-dev
2017-Dec-24 03:47 UTC
[llvm-dev] BackendUtil's EmitAssemblyHelper::EmitAssembly generated call in wrong order
Hi LLVM developers,
A C++ testcase for PR35737
#include <iostream>
int bar() {
std::cout << "bar" << std::endl;
return 1;
}
int main() {
std::cout << "return: " << bar() << std::endl;
return 0;
}
Actual output:
return: bar
1
Expected output:
bar
return: 1
Workaround to edit LLVM IR:
--- PR35737.ll 2017-12-24 11:20:12.012346163 +0800
+++ PR35737-workaround.ll 2017-12-24 11:42:25.303256968 +0800
@@ -62,8 +62,8 @@
entry:
%retval = alloca i32, align 4
store i32 0, i32* %retval, align 4
- %call = call dereferenceable(272) %"class.std::basic_ostream"*
@_ZStlsISt11char_traitsIcEERSt13basic_ostreamIcT_ES5_PKc(%"class.std::basic_ostream"*
dereferenceable(272) @_ZSt4cout, i8* getelementptr inbounds ([9 x i8],
[9 x i8]* @.str.1, i32 0, i32 0))
%call1 = call i32 @_Z3barv()
+ %call = call dereferenceable(272) %"class.std::basic_ostream"*
@_ZStlsISt11char_traitsIcEERSt13basic_ostreamIcT_ES5_PKc(%"class.std::basic_ostream"*
dereferenceable(272) @_ZSt4cout, i8* getelementptr inbounds ([9 x i8],
[9 x i8]* @.str.1, i32 0, i32 0))
%call2 = call dereferenceable(272) %"class.std::basic_ostream"*
@_ZNSolsEi(%"class.std::basic_ostream"* %call, i32 %call1)
%call3 = call dereferenceable(272) %"class.std::basic_ostream"*
@_ZNSolsEPFRSoS_E(%"class.std::basic_ostream"* %call2,
%"class.std::basic_ostream"* (%"class.std::basic_ostream"*)*
@_ZSt4endlIcSt11char_traitsIcEERSt13basic_ostreamIT_T0_ES6_)
ret i32 0
Then,
$ llc PR35737-workaround.ll
$ clang++ PR35737-workaround.s
$ ./a.out
bar
return: 1
Please give me some advice, thanks a lot!
--
Regards,
Leslie Zhai - https://reviews.llvm.org/p/xiangzhai/