2011/7/20 Richard Guenther <richard.guent...@gmail.com>:
> On Wed, Jul 20, 2011 at 3:05 PM, Kai Tietz <ktiet...@googlemail.com> wrote:
>> Hello,
>>
>> this is the revised version of the partial pre-approved patch for preserving
>> type-casts from/to boolean-types. It fixes additionally the regression in
>> tree-ssa/builtin-expect-5.c testcase, which was caused by
>> fold_builtin_expect.
>> Additionally there was a regression in gcc.dg/pr28685-1.c, which is fixed by
>> the change in tree-ssa-forwprop.c's function simplify_bitwise_binary. This
>> is just temporary necessary. As soon as we are boolifying comparisons in
>> gimplifier, the pattern-matching in tree-ssa-reassoc will match for 2
>> branched cases
>> again and we can remove the hunk from forward-propagation again.
>
> Hm, if we can't apply this pieces without regressions we shouldn't. They
> can then wait for the boolification patch.
>
> Can you explain the fold_builtin_expect change? I'm lost in the maze
> of inner/inner_arg0/arg0 renaming game. It looks as if the patch only
> moves stuff - but that can't possibly be the case. So, what's going on
> there?
Well, the issue is here that fold_builtin_expect checks here for a
comparison. If this comparison was created initially with a
boolean-type, the cast to 'long' will be in tree arg0 = (long)
CMP-with-boolean-type, as we are preserving here casts from
boolean-types (see the fold-const change). So we need to see through
this casts to match the compare and call cases. So I moved this "see
through" part before first pattern-match and introduced here a
helper-variable inner_arg0 to avoid double while-loop. The "inner"
variable might get invalid
...
if (COMPARISON_CLASS_P (inner)
&& TREE_CODE (TREE_OPERAND (inner, 1)) == INTEGER_CST)
inner = TREE_OPERAND (inner, 0);
...
These are those "prefixed casts" you were asking in the other patch about.
Regards,
Kai
