https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93081
Bug ID: 93081
Summary: insertation followed by another inseration to the same
location is not optimized away
Product: gcc
Version: 10.0
Status: UNCONFIRMED
Keywords: missed-optimization, TREE
Severity: enhancement
Priority: P3
Component: tree-optimization
Assignee: pinskia at gcc dot gnu.org
Reporter: pinskia at gcc dot gnu.org
Target Milestone: ---
Testcase:
/* { dg-do compile } */
/* { dg-options "-O2 -fdump-tree-optimized" } */
#define vector __attribute__((__vector_size__(16) ))
vector int f(vector int a, int b, int c)
{
a[0] = b;
a[0] = c;
return a;
}
/* { dg-final { scan-tree-dump-times "BIT_INSERT_EXPR" 1 "optimized" } } */
--- CUT ---
Code added to match.pd which will fix it:
/* Inserting into the same location as previously just over writes the
location. */
(simplify
(bit_insert (bit_insert @0 @1 @2) @3 @2)
(bit_insert @0 @3 @2))
