https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110479
Bug ID: 110479
Summary: Unnecessary register move
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: enhancement
Priority: P3
Component: rtl-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: tkoenig at gcc dot gnu.org
Target Milestone: ---
May be related to / a dup of PR110240.
The function
unsigned int bar(unsigned int a)
{
return 1u << (((a >> 10) & 3) + 3);
}
is compiled, with a relatively recent trunk and -O3, to
bar:
.LFB12:
.cfi_startproc
shrl $10, %edi
movl $1, %eax
movl %edi, %ecx
andl $3, %ecx
addl $3, %ecx
sall %cl, %eax
ret
where the register move seems unnecessary.
