https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111805
Bug ID: 111805
Summary: suboptimal codegen of variant<string, bool>
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: hiraditya at msn dot com
Target Milestone: ---
#include<variant>
#include<string>
std::string foo() {
std::variant<std::string, bool> v {"abc"};
return std::get<0>(v);
}
g++-13.2 -O2 -std=c++20
foo[abi:cxx11]():
lea rdx, [rdi+16]
mov BYTE PTR [rdi+18], 99
mov rax, rdi
mov QWORD PTR [rdi], rdx
mov edx, 25185
mov WORD PTR [rdi+16], dx
mov QWORD PTR [rdi+8], 3
mov BYTE PTR [rdi+19], 0
ret
clang++ -O2 -std=c++20
foo(): # @foo()
mov rax, rdi
mov byte ptr [rdi], 6
mov dword ptr [rdi + 1], 6513249
ret
https://godbolt.org/z/nTv5rYanM
