[Bug middle-end/43182] New: gcc could not vectorize this simple loop (un-handled data-ref)
changpeng dot fang at amd dot com
gcc-bugzilla@gcc.gnu.org
Thu Feb 25 23:37:00 GMT 2010
gcc 4.5 can not vectorize this simple loop:
void foo(int a[], int n) {
int i;
for(i=1; i< n; i++)
a[i] = a[0];
}
"gcc -O3 -fdump-tree-vect-all -c foo.c" shows:
foo.c:3: note: not vectorized: unhandled data-ref
foo.c:3: note: bad data references.
foo.c:1: note: vectorized 0 loops in function.
It seems gcc gets confused at a[0] and gives up vectorization. There
is no dependence in this loop, and we should teach gcc to handle a[0]
to vectorize it.
--
Summary: gcc could not vectorize this simple loop (un-handled
data-ref)
Product: gcc
Version: 4.5.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: middle-end
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: changpeng dot fang at amd dot com
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43182
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