https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114508
Bug ID: 114508
Summary: Missed optimization of Dead Code Elimination
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 noticed that the code below can be optimized by Dead Code
Elimination, but gcc -O3 missed it.
Reduced code:
https://godbolt.org/z/j9a3Mza3d
int a, b;
void func(int g, int d){
int x=g+d;
if(x>0){
d--;
int t=g+d;
if(t<0){ //false
b=1; //dead code
}
}
}
GCC -O3:
func(int, int):
lea eax, [rdi+rsi]
test eax, eax
jle .L1
lea eax, [rdi-1+rsi]
test eax, eax
js .L4
.L1:
ret
.L4:
mov DWORD PTR b[rip], 1
ret
Expected code (Clang):
func(int, int): # @func(int, int)
ret
Thank you very much for your time and effort! We look forward to hearing from
you.
