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[Bug c++/84824] DCE fails to remove dead code of std::function constructor
- From: "manjian2006 at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Mon, 12 Mar 2018 08:56:19 +0000
- Subject: [Bug c++/84824] DCE fails to remove dead code of std::function constructor
- Auto-submitted: auto-generated
- References: <bug-84824-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84824
--- Comment #5 from linzj <manjian2006 at gmail dot com> ---
Change the function call to printf to asm like:
int main() {
// printf("%d", getFunc(1)(1, 1));
asm volatile(""
:
: "r"(getFunc(1)(1, 1)));
return 0;
}
Will generate the concise code.
I think
# USE = anything
# CLB = anything
printfD.984 ("%d", _1);
Force the artifact anonymous auto variable to escape the current scope.