On Wed, Jul 13, 2011 at 11:00 AM, Kai Tietz <ktiet...@googlemail.com> wrote:
> Hello,
>
> this patch fixes that for replaced uses, we call fold_stmt_inplace.
> Additionally
> it adds to fold_gimple_assign the canonical form for X !=/== 1 -> X ==/!= 0
> for
> X with one-bit precision type.
>
> ChangeLog gcc/
>
> 2011-07-13 Kai Tietz <kti...@redhat.com>
>
> * gimple-fold.c (fold_gimple_assign): Add normalization
> for compares of 1-bit integer precision operands.
> * tree-ssa-propagate.c (replace_uses_in): Call
> fold_stmt_inplace on modified statement.
err - sure not. The caller already does that.
Breakpoint 5, substitute_and_fold (get_value_fn=0xc269ae <get_value>,
fold_fn=0, do_dce=1 '\001')
at /space/rguenther/src/svn/trunk/gcc/tree-ssa-propagate.c:1134
1134 if (get_value_fn)
D.2696_8 = a_1(D) != D.2704_10;
(gdb) n
1135 did_replace |= replace_uses_in (stmt, get_value_fn);
(gdb)
1138 if (did_replace)
(gdb) call debug_gimple_stmt (stmt)
D.2696_8 = a_1(D) != 1;
(gdb) p did_replace
$1 = 1 '\001'
(gdb) n
1139 fold_stmt (&oldi);
so figure out why fold_stmt does not do its work instead. Which I
quickly checked in gdb and it dispatches to fold_binary with
boolean-typed arguments as a_1 != 1 where you can see the
canonical form for this is !(int) a_1 because of a bug I think.
/* bool_var != 1 becomes !bool_var. */
if (TREE_CODE (TREE_TYPE (arg0)) == BOOLEAN_TYPE && integer_onep (arg1)
&& code == NE_EXPR)
return fold_build1_loc (loc, TRUTH_NOT_EXPR, type,
fold_convert_loc (loc, type, arg0));
at least I don't see why we need to convert arg0 to the type of the
comparison.
You need to improve your debugging skills and see why existing
transformations are not working before adding new ones.
Richard.
> ChangeLog gcc/testsuite
>
> 2011-07-13 Kai Tietz <kti...@redhat.com>
>
> * gcc.dg/tree-ssa/fold-1.c: New test.
>
> Bootstrapped and regression tested for x86_64-pc-linux-gnu. Ok for apply?
>
> Regards,
> Kai
>
> Index: gcc/gcc/gimple-fold.c
> ===================================================================
> --- gcc.orig/gcc/gimple-fold.c 2011-07-13 10:37:32.000000000 +0200
> +++ gcc/gcc/gimple-fold.c 2011-07-13 10:39:05.100843400 +0200
> @@ -815,6 +815,17 @@ fold_gimple_assign (gimple_stmt_iterator
> gimple_assign_rhs2 (stmt));
> }
>
> + if (!result && (subcode == EQ_EXPR || subcode == NE_EXPR)
> + && INTEGRAL_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (stmt)))
> + && TYPE_PRECISION (TREE_TYPE (gimple_assign_rhs1 (stmt))) == 1
> + && integer_onep (gimple_assign_rhs2 (stmt)))
> + result = build2_loc (loc, (subcode == EQ_EXPR ? NE_EXPR : EQ_EXPR),
> + TREE_TYPE (gimple_assign_lhs (stmt)),
> + gimple_assign_rhs1 (stmt),
> + fold_convert_loc (loc,
> + TREE_TYPE (gimple_assign_rhs1 (stmt)),
> + integer_zero_node));
> +
> if (!result)
> result = fold_binary_loc (loc, subcode,
> TREE_TYPE (gimple_assign_lhs (stmt)),
> Index: gcc/gcc/testsuite/gcc.dg/tree-ssa/fold-1.c
> ===================================================================
> --- /dev/null 1970-01-01 00:00:00.000000000 +0000
> +++ gcc/gcc/testsuite/gcc.dg/tree-ssa/fold-1.c 2011-07-13
> 10:50:38.294367800 +0200
> @@ -0,0 +1,9 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O2 -fdump-tree-optimized" } */
> +
> +int foo (_Bool a, _Bool b)
> +{
> + return a != ((b | !b));
> +}
> +/* { dg-final { scan-tree-dump-not " != 1" "optimized" } } */
> +/* { dg-final { cleanup-tree-dump "optimized" } } */
> Index: gcc/gcc/tree-ssa-propagate.c
> ===================================================================
> --- gcc.orig/gcc/tree-ssa-propagate.c 2011-07-13 10:37:42.000000000 +0200
> +++ gcc/gcc/tree-ssa-propagate.c 2011-07-13 10:40:25.688576800 +0200
> @@ -904,6 +904,8 @@ replace_uses_in (gimple stmt, ssa_prop_g
>
> propagate_value (use, val);
>
> + fold_stmt_inplace (stmt);
> +
> replaced = true;
> }
>
