https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91329
Bug ID: 91329
Summary: Unnecessary call to __cxa_throw_bad_array_new_length
Product: gcc
Version: 10.0
Status: UNCONFIRMED
Keywords: missed-optimization
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: antoshkka at gmail dot com
Target Milestone: ---
For the code
int* test(int i) {
return new int[i];
}
The following assembly is generated:
test(int):
movsx rdi, edi
sub rsp, 8
movabs rax, 2305843009213693950
cmp rdi, rax
ja .L2
sal rdi, 2
add rsp, 8
jmp operator new[](unsigned long)
test(int) [clone .cold]:
.L2:
call __cxa_throw_bad_array_new_length
However the `i * sizeof(int)` can not be greater than `2305843009213693950`. So
the checks should be skipped.
Optimal assembly should look close to:
test(int):
movsx rdi, edi
sal rdi, 2
jmp operator new[](unsigned long)
