https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111718
Bug ID: 111718
Summary: Missed optimization of '(a+a)/a'
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: 652023330028 at smail dot nju.edu.cn
Target Milestone: ---
Hello, we found some optimizations (regarding Arithmetic optimization) that GCC
may have missed. We would greatly appreicate if you can take a look and let us
know what you think.
Given the following code:
https://godbolt.org/z/5de17zvz9
unsigned n1,n2;
void func1(unsigned a){
if(a>10&&a<20){
n1=a+a;
n2=(a+a)/a;
}
}
We note that `(a+a)/a` should be optimized to `2`, but gcc-trunk -O3 does not:
func1(unsigned int):
lea eax, [rdi-11]
cmp eax, 8
ja .L1
lea eax, [rdi+rdi]
xor edx, edx
mov DWORD PTR n1[rip], eax
div edi
mov DWORD PTR n2[rip], eax
.L1:
ret
Thank you very much for your time and effort! We look forward to hearing from
you.
