https://gcc.gnu.org/bugzilla/show_bug.cgi?id=118267
Bug ID: 118267
Summary: Suboptimal code for bool bitfield tests
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: law at gcc dot gnu.org
Target Milestone: ---
This is extracted from bz99918 where someone added a testcase that likely is
unrelated to Martin's and where we don't know if that additional testcase is a
regression or not.
Another simple example:
#include <cstdint>
struct SomeClass {
bool cfg1 : 1;
bool cfg2 : 1;
bool cfg3 : 1;
bool check() const noexcept { return cfg1 || cfg2 || cfg3; }
};
bool check(const SomeClass& rt) {
return rt.check();
}
Emits:
check(SomeClass const&):
movzx edx, BYTE PTR [rdi]
mov eax, edx
and eax, 1
jne .L1
mov eax, edx
shr al
and eax, 1
je .L4
.L1:
ret
.L4:
mov eax, edx
shr al, 2
and eax, 1
ret
While it should:
check(SomeClass const&):
test byte ptr [rdi], 7
setne al
ret
