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Date: Fri, 03 Sep 2010 15:58:00 -0000
Subject: [Bug tree-optimization/45522]  New: VRP misses oppurtunity for statement folding.
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From: "hubicka at gcc dot gnu dot org" <gcc-bugzilla@gcc.gnu.org>
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Hi,
compiling the attached testcase (reduced from tree.c) with -O2 leads to vrp
folding:
  if (D.2762_2 == 6)
    goto <bb 3>;
  else
    goto <bb 9>;

<bb 3>:
  D.2766_5 = (int) D.2762_2;
  D.2767_6 = tree_code_type[D.2766_5];

into
  D.2762_2 = type_1(D)->base.code;
  if (D.2762_2 == 6)
    goto <bb 3>;
  else
    goto <bb 9>;

<bb 3>:
  D.2766_5 = 6;
  D.2767_6 = tree_code_type[6];

this is good transform, however tree_code_type is constant initialized array
and we miss possibility to fold it into constant until expansion triggering
code in expr.c I would like to retire.

We can fold tree_code_type[6], so apparently just no one calls fold_gimple_stmt
on it?


-- 
           Summary: VRP misses oppurtunity for statement folding.
           Product: gcc
           Version: 4.6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: hubicka at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45522