[patch gimplify]: Make sure comparison using boolean-type after gimplification
Richard Guenther
richard.guenther@gmail.com
Thu May 26 12:00:00 GMT 2011
On Thu, May 26, 2011 at 1:05 PM, Kai Tietz <ktietz70@googlemail.com> wrote:
> 2011/5/26 Richard Guenther <richard.guenther@gmail.com>:
>> On Thu, May 26, 2011 at 12:20 PM, Kai Tietz <ktietz@redhat.com> wrote:
>>> Hello,
>>>
>>> this patch ensures that after gimplification also comparison expressions using FE's boolean_type_node. As we need to deal here with C/C++'s (obj-c/c++ and java's), Ada's, and Fortran's specific boolean types, this patch alters some checks in tree-cfg for Ada's sake, and we need to deal in fold-const about type-conversion of comparisons special.
>>> Additionally it takes care that in forwprop pass we don't do type hoising for boolean types.
>>>
>>> ChangeLog
>>>
>>> 2011-05-26 Kai Tietz
>>>
>>> * gimplify.c (gimple_boolify): Boolify all comparison
>>> expressions.
>>> (gimplify_expr): Use 'useless_type_conversion_p' for comparing
>>> org_type with boolean_type_node for TRUTH-expressions and comparisons.
>>> * fold-const.c (fold_unary_loc): Handle comparison conversions with
>>> boolean-type special.
>>> * tree-cfg.c (verify_gimple_comparison): Adjust check for boolean
>>> or compatible types.
>>> (verify_gimple_assign_unary): Likewise.
>>> * tree-ssa-forwprop.c (forward_propagate_comparison): Handle
>>> boolean case special.
>>>
>>> Tested on x86_64-pc-linux-gnu (multilib) with regression test for all standard languages (C, C++, Obj-C, Fortran, Java) plus Obj-C++ and Ada. Ok for apply?
>>
>> It obviously isn't ok to apply before a patch has gone in that will resolve
>> all of the FAILs you specify. Comments on the patch:
>>
>> @@ -7281,9 +7284,28 @@ gimplify_expr (tree *expr_p, gimple_seq
>> plain wrong if bitfields are involved. */
>> {
>> tree type = TREE_TYPE (TREE_OPERAND (*expr_p, 1));
>> + tree org_type = TREE_TYPE (*expr_p);
>> +
>> + if (!useless_type_conversion_p (org_type, boolean_type_node))
>> + {
>> + TREE_TYPE (*expr_p) = boolean_type_node;
>> + *expr_p = fold_convert_loc (saved_location, org_type, *expr_p);
>> + ret = GS_OK;
>> + goto dont_recalculate;
>> + }
>>
>> The above should be only done for !AGGREGATE_TYPE_P. Probably then
>> the strange dont_recalcuate goto can go away as well.
>
> I thought so too, but boolification is required for all kind of
> comparisons. This goto is a bit hacky, but the best way to prevent
> here an useless recalculation. Without doing this, we get
> bootstrap/regression test failures, as in tree-cfg we check that
> comparison type is of boolean (or compatible kind).
That doesn't make sense if you look at the other two cases which
both will return GS_OK and thus re-enter this. The aggregate
variable size path also will use memcmp which returns int,so
first boolifying doesn't make sense.
>> if (!AGGREGATE_TYPE_P (type))
>> - goto expr_2;
>> + {
>> + enum gimplify_status r0, r1;
>> +
>> + r0 = gimplify_expr (&TREE_OPERAND (*expr_p, 0), pre_p,
>> + post_p, is_gimple_val, fb_rvalue);
>> + r1 = gimplify_expr (&TREE_OPERAND (*expr_p, 1), pre_p,
>> + post_p, is_gimple_val, fb_rvalue);
>> +
>> + ret = MIN (r0, r1);
>> + }
>> +
>>
>> why change this?
>
> This part can be reverted to the goto expr_2 again.
>
>> @@ -7641,6 +7641,12 @@ fold_unary_loc (location_t loc, enum tre
>> }
>> else if (COMPARISON_CLASS_P (arg0))
>> {
>> + /* Don't optimize type change, if op0 is of kind boolean_type_node.
>> + Otherwise this will lead to race-condition on gimplification
>> + trying to boolify comparison expression. */
>> + if (TREE_TYPE (op0) == boolean_type_node)
>> + return NULL_TREE;
>> +
>> if (TREE_CODE (type) == BOOLEAN_TYPE)
>> {
>> arg0 = copy_node (arg0);
>>
>> The code leading here looks quite strange to me ...
>
> Issue is that Fortran (and this is the cause for this
> boolean_type_node check) has more then one boolean type. Gimplifier
> normalizes to boolean_type_node. If now a different boolean-type
> (with different mode) of Fortran is used, it leads to an endless-loop
> in type conversion. An example boolean-kind(mode-size=1) and
> boolean-kind(mode-size=2) are no useless type conversion. So by
> gimplifier type gets set to boolean-kind(mode-size=1) (if this is
> default boolean_type_node's definition), and then casted to
> boolean-kind(mode-size=2) expression.
I said the whole code looks strange, it should be reworked instead
of addign this kind of other non-obviousness.
Richard.
>
>> tree
>> fold_unary_loc (location_t loc, enum tree_code code, tree type, tree op0)
>> {
>> ...
>> if (TREE_CODE_CLASS (code) == tcc_unary)
>> {
>> ...
>> else if (COMPARISON_CLASS_P (arg0))
>> {
>> if (TREE_CODE (type) == BOOLEAN_TYPE)
>> {
>> arg0 = copy_node (arg0);
>> TREE_TYPE (arg0) = type;
>> return arg0;
>> }
>> else if (TREE_CODE (type) != INTEGER_TYPE)
>> return fold_build3_loc (loc, COND_EXPR, type, arg0,
>> fold_build1_loc (loc, code, type,
>> integer_one_node),
>> fold_build1_loc (loc, code, type,
>> integer_zero_node));
>> }
>>
>> so, for any tcc_unary, like NEGATE_EXPR, with BOOLEAN_TYPE,
>> return arg0 ... sure. Same for the 2nd case. ~ (a == b) isn't
>> the same as a == b ? ~1 : ~0. I _suppose_ those cases were
>> ment for CONVERT_EXPR_CODE_P (code) instead of all of tcc_unary,
>> in which case they should be dropped or moved below where we
>> handle conversions explicitly.
>>
>> That said - does anyone remember anything about that above code?
>> Trying to do some svn blame history tracking now ...
>>
>> Richard.
>>
>>> The following tests are failing due this change (what is to be expected here and needs some additional handling in forwprop).
>>> FAIL: gcc.dg/binop-xor1.c scan-tree-dump-times optimized "<bb[^>]*>" 5
>>> FAIL: gcc.dg/binop-xor1.c scan-tree-dump-times optimized "\^" 1
>>> FAIL: gcc.dg/binop-xor3.c scan-tree-dump-times optimized "<bb[^>]*>" 1
>>> FAIL: gcc.dg/binop-xor3.c scan-tree-dump-times optimized "\^" 1
>>> XPASS: gcc.dg/tree-ssa/20030807-7.c scan-tree-dump-times vrp1 "if " 1
>>> FAIL: gcc.dg/tree-ssa/builtin-expect-5.c scan-tree-dump forwprop1 "builtin_expect[^\n]*, 1\);\n[^\n]*if"
>>> FAIL: gcc.dg/tree-ssa/pr21031.c scan-tree-dump-times forwprop1 "Replaced" 2
>>> FAIL: gcc.dg/tree-ssa/pr30978.c scan-tree-dump optimized "e_. = a_..D. > 0;"
>>> FAIL: gcc.dg/tree-ssa/ssa-fre-6.c scan-tree-dump-times fre1 "Replaced " 5
>>> FAIL: gcc.dg/tree-ssa/vrp47.c scan-tree-dump-times dom1 "x[^ ]* & y" 1
>>> FAIL: gcc.dg/tree-ssa/vrp47.c scan-tree-dump-times vrp1 "x[^ ]* \^ 1" 1
>>> FAIL: gcc.dg/vect/pr49038.c execution test
>>> FAIL: gcc.dg/vect/pr49038.c -flto execution test
>>> FAIL: gcc.target/i386/andor-2.c scan-assembler-not sete
>>>
>>> The Ada, Obj-C, Obj-C++, C++, Fortran, and Java testsuite don't show any new regressions by this.
>>>
>>> Some failing testcases are simply caused by different folding behavior and producing simplier code. The binop-xor tests 1 and 3 might be better removed for now, or marked as being expect to fail. The cause for their failing is in doing tree-analysis via fold-const on gimplified trees, which now don't allow folding here to look through.
>>> To illustrate required changes for other tests, I attach here some required changes for testsuite
>>>
>>> Index: gcc.dg/tree-ssa/pr30978.c
>>> ===================================================================
>>> --- gcc.dg/tree-ssa/pr30978.c (revision 174264)
>>> +++ gcc.dg/tree-ssa/pr30978.c (working copy)
>>> @@ -10,5 +10,5 @@
>>> return e;
>>> }
>>>
>>> -/* { dg-final { scan-tree-dump "e_. = a_..D. > 0;" "optimized" } } */
>>> +/* { dg-final { scan-tree-dump " = a_..D. > 0;\n[^\n]*e_. = \\\(int\\\)" "optimized" } } */
>>> /* { dg-final { cleanup-tree-dump "optimized" } } */
>>>
>>> Index: gcc.dg/tree-ssa/builtin-expect-5.c
>>> ===================================================================
>>> --- gcc.dg/tree-ssa/builtin-expect-5.c (revision 174264)
>>> +++ gcc.dg/tree-ssa/builtin-expect-5.c (working copy)
>>> @@ -11,5 +11,5 @@
>>>
>>> /* { dg-final { scan-tree-dump-times { if } 2 "forwprop1"} } */
>>> /* { dg-final { scan-tree-dump {builtin_expect[^\n]*, 0\);\n[^\n]*if} "forwprop1"} } */
>>> -/* { dg-final { scan-tree-dump {builtin_expect[^\n]*, 1\);\n[^\n]*if} "forwprop1"} } */
>>> +/* { dg-final { scan-tree-dump {builtin_expect[^\n]*, 1\);} "forwprop1"} } */
>>> /* { dg-final { cleanup-tree-dump "forwprop?" } } */
>>>
>>> Index: gcc.dg/tree-ssa/pr21031.c
>>> ===================================================================
>>> --- gcc.dg/tree-ssa/pr21031.c (revision 174264)
>>> +++ gcc.dg/tree-ssa/pr21031.c (working copy)
>>> @@ -16,5 +16,5 @@
>>> return 0;
>>> }
>>>
>>> -/* { dg-final { scan-tree-dump-times "Replaced" 2 "forwprop1"} } */
>>> +/* { dg-final { scan-tree-dump-times "Replaced" 1 "forwprop1"} } */
>>> /* { dg-final { cleanup-tree-dump "forwprop1" } } */
>>>
>>> Index: gcc.dg/tree-ssa/ssa-fre-6.c
>>> ===================================================================
>>> --- gcc.dg/tree-ssa/ssa-fre-6.c (revision 174264)
>>> +++ gcc.dg/tree-ssa/ssa-fre-6.c (working copy)
>>> @@ -2,5 +2,5 @@
>>> /* { dg-options "-O -fdump-tree-fre1-details" } */
>>>
>>> int i; int foo(void) { i = 2; int j = i * 2; int k = i + 2; return j == k; }
>>> -/* { dg-final { scan-tree-dump-times "Replaced " 5 "fre1" } } */
>>> +/* { dg-final { scan-tree-dump-times "Replaced " 6 "fre1" } } */
>>> /* { dg-final { cleanup-tree-dump "fre1" } } */
>>>
>>> Regards,
>>> Kai
>>>
>
> Regards,
> Kai
>
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