https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96586
Bug ID: 96586
Summary: suboptimal code generated for condition expression
Product: gcc
Version: 10.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: zhongyunde at tom dot com
Target Milestone: ---
For the following case, we can easy known the while loop will execute once, but
with newest gcc 10.2, it still generated suboptimal code with condition
expression.
void Proc_7 (int Int_Par_Ref);
void Proc_2 (int *Int_Par_Ref);
int main ()
{
int Int_1_Loc;
int Int_2_Loc;
int Int_3_Loc;
/* Initializations */
Int_1_Loc = 2;
Int_2_Loc = 3;
while (Int_1_Loc < Int_2_Loc)
{
Proc_7 (0);
Int_1_Loc += 1;
} /* while */
Int_1_Loc = 1;
Proc_2 (&Int_1_Loc);
return 0;
}
============== the key assemble of the while loop ===========
.L2:
.loc 1 18 7 view .LVU10
.loc 1 20 7 view .LVU11
.loc 1 20 14 is_stmt 0 view .LVU12
mov edi, 5
call Proc_7(int)
.LVL1:
.loc 1 22 7 is_stmt 1 view .LVU13
.loc 1 22 17 is_stmt 0 view .LVU14
mov eax, DWORD PTR [rsp+12]
add eax, 1
mov DWORD PTR [rsp+12], eax
.loc 1 16 5 is_stmt 1 view .LVU15
.loc 1 16 22 view .LVU16
cmp eax, 2
jle .L2
