http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33512
--- Comment #14 from Kai Tietz <ktietz at gcc dot gnu.org> 2012-04-24 08:30:49
UTC ---
Hmm, I have right now in my tree
Index: tree-ssa-forwprop.c
===================================================================
--- tree-ssa-forwprop.c (revision 186753)
+++ tree-ssa-forwprop.c (working copy)
@@ -1912,17 +1912,25 @@
/* Simplify (A & B) OP0 (C & B) to (A OP0 C) & B. */
if (def1_code == def2_code
- && def1_code == BIT_AND_EXPR
- && operand_equal_for_phi_arg_p (gimple_assign_rhs2 (def1),
- gimple_assign_rhs2 (def2)))
+ && def1_code == BIT_AND_EXPR)
{
- tree b = gimple_assign_rhs2 (def1);
- tree a = def1_arg1;
- tree c = def2_arg1;
- tree inner = fold_build2 (code, TREE_TYPE (arg2), a, c);
+ tree inner, a = NULL_TREE, b = NULL_TREE, c = NULL_TREE;
+
+ if (operand_equal_for_phi_arg_p (def1_arg2, def2_arg2))
+ { b = def1_arg2; a = def1_arg1; c = def2_arg1; }
+ else if (operand_equal_for_phi_arg_p (def1_arg1, def2_arg1))
+ { b = def1_arg1; a = def1_arg2; c = def2_arg2; }
+ else if (operand_equal_for_phi_arg_p (def1_arg1, def2_arg2))
+ { b = def1_arg1; a = def1_arg2; c = def2_arg1; }
+ else if (operand_equal_for_phi_arg_p (def1_arg2, def2_arg1))
+ { b = def1_arg2; a = def1_arg1; c = def2_arg2; }
+ if (a && c)
+ inner = fold_build2 (code, TREE_TYPE (arg2), a, c);
+ if (!a || !b || !c)
+ ;
/* If A OP0 C (this usually means C is the same as A) is 0
then fold it down correctly. */
- if (integer_zerop (inner))
+ else if (integer_zerop (inner))
{
gimple_assign_set_rhs_from_tree (gsi, inner);
update_stmt (stmt);
It has the advantage of handling also cases for (A & B) OP0 (C & B) to (A OP0
C) & B, (B & A) OP0 (C & B) to (A OP0 C) & B, (A & B) OP0 (B & C) to (A OP0 C)
& B, and (B & A) OP0 (B & C) to (A OP0 C) & B.
It bootstraps fine.
