[Bug tree-optimization/27497] New: store ccp does not handle constant aggregate refs of STRING_CSTs

["rguenth at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>]

Testcase:

/* { dg-do compile } */
/* { dg-options "-O2 -fdump-tree-optimized" } */

static const char f[3] = "?";

int foo()
{
  int i = 0;
  return f[i] != '?';
}

/* { dg-final { scan-tree-dump "return 0;" "optimized" } } */
/* { dg-final { cleanup-tree-dump "optimized" } } */

Problem is two-fold, for once, fold_const_aggregate_ref does not handle
STRING_CST, second, evaluate_stmt triggers the likelyvalue == CONSTANT
path only, and ccp_fold does not call fold_const_aggregate_ref.

RTL handles this.  I have a patch.


-- 
           Summary: store ccp does not handle constant aggregate refs of
                    STRING_CSTs
           Product: gcc
           Version: 4.2.0
            Status: UNCONFIRMED
          Keywords: missed-optimization, TREE
          Severity: enhancement
          Priority: P3
         Component: tree-optimization
        AssignedTo: rguenth at gcc dot gnu dot org
        ReportedBy: rguenth at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27497