Re: [patch tree-optimization]: [2 of 3]: Boolify compares & more

[Richard Guenther <richard.guenther@gmail.com>]

On Fri, Jul 8, 2011 at 1:32 PM, Kai Tietz <ktietz70@googlemail.com> wrote:
> 2011/7/8 Richard Guenther <richard.guenther@gmail.com>:
>> On Thu, Jul 7, 2011 at 6:07 PM, Kai Tietz <ktietz70@googlemail.com> wrote:
>>> Hello,
>>>
>>> This patch - second of series - adds boolification of comparisions in
>>> gimplifier.  For this
>>> casts from/to boolean are marked as not-useless. And in fold_unary_loc
>>> casts to non-boolean integral types are preserved.
>>> The hunk in tree-ssa-forwprop.c in combine_cond-expr_cond is not strictly
>>> necessary - as long as fold-const handles 1-bit precision bitwise-expression
>>> with truth-logic - but it has shown to short-cut some expensier folding. So
>>> I kept it within this patch.
>>
>> Please split it out.  Also ...
>>
>>>
>>> The adjusted testcase gcc.dg/uninit-15.c indicates that due
>>> optimization we loose
>>> in this case variables declaration.  But this might be to be expected.
>>>
>>> In vectorization we have a regression in gcc.dg/vect/vect-cond-3.c
>>> test-case.  It's caused
>>> by always having boolean-type on conditions.  So vectorizer sees
>>> different types, which
>>> aren't handled by vectorizer right now.  Maybe this issue could be
>>> special-cased for
>>> boolean-types in tree-vect-loop, by making operand for used condition
>>> equal to vector-type.
>>> But this is a subject for a different patch and not addressed by this series.
>>>
>>> There is a regressions in tree-ssa/vrp47.c, and the fix is addressed
>>> by the 3rd patch of this
>>> series.
>>>
>>> Bootstrapped and regression tested for all standard-languages (plus
>>> Ada and Obj-C++) on host x86_64-pc-linux-gnu.
>>>
>>> Ok for apply?
>>>
>>> Regards,
>>> Kai
>>>
>>>
>>> ChangeLog
>>>
>>> 2011-07-07  Kai Tietz  <ktietz@redhat.com>
>>>
>>>        * fold-const.c (fold_unary_loc): Preserve
>>>        non-boolean-typed casts.
>>>        * gimplify.c (gimple_boolify): Handle boolification
>>>        of comparisons.
>>>        (gimplify_expr): Boolifiy non aggregate-typed
>>>        comparisons.
>>>        * tree-cfg.c (verify_gimple_comparison): Check result
>>>        type of comparison expression.
>>>        * tree-ssa.c (useless_type_conversion_p): Preserve incompatible
>>>        casts from/to boolean,
>>>        * tree-ssa-forwprop.c (combine_cond_expr_cond): Add simplification
>>>        support for one-bit-precision typed X for cases X != 0 and X == 0.
>>>        (forward_propagate_comparison): Adjust test of condition
>>>        result.
>>>
>>>
>>>        * gcc.dg/tree-ssa/builtin-expect-5.c: Adjusted.
>>>        * gcc.dg/tree-ssa/pr21031.c: Likewise.
>>>        * gcc.dg/tree-ssa/pr30978.c: Likewise.
>>>        * gcc.dg/tree-ssa/ssa-fre-6.c: Likewise.
>>>        * gcc.dg/binop-xor1.c: Mark it as expected fail.
>>>        * gcc.dg/binop-xor3.c: Likewise.
>>>        * gcc.dg/uninit-15.c: Adjust reported message.
>>>
>>> Index: gcc-head/gcc/fold-const.c
>>> ===================================================================
>>> --- gcc-head.orig/gcc/fold-const.c
>>> +++ gcc-head/gcc/fold-const.c
>>> @@ -7665,11 +7665,11 @@ fold_unary_loc (location_t loc, enum tre
>>>             non-integral type.
>>>             Do not fold the result as that would not simplify further, also
>>>             folding again results in recursions.  */
>>> -         if (INTEGRAL_TYPE_P (type))
>>> +         if (TREE_CODE (type) == BOOLEAN_TYPE)
>>>            return build2_loc (loc, TREE_CODE (op0), type,
>>>                               TREE_OPERAND (op0, 0),
>>>                               TREE_OPERAND (op0, 1));
>>> -         else
>>> +         else if (!INTEGRAL_TYPE_P (type))
>>>            return build3_loc (loc, COND_EXPR, type, op0,
>>>                               fold_convert (type, boolean_true_node),
>>>                               fold_convert (type, boolean_false_node));
>>> Index: gcc-head/gcc/gimplify.c
>>> ===================================================================
>>> --- gcc-head.orig/gcc/gimplify.c
>>> +++ gcc-head/gcc/gimplify.c
>>> @@ -2842,18 +2842,23 @@ gimple_boolify (tree expr)
>>>
>>>     case TRUTH_NOT_EXPR:
>>>       TREE_OPERAND (expr, 0) = gimple_boolify (TREE_OPERAND (expr, 0));
>>> -      /* FALLTHRU */
>>>
>>> -    case EQ_EXPR: case NE_EXPR:
>>> -    case LE_EXPR: case GE_EXPR: case LT_EXPR: case GT_EXPR:
>>>       /* These expressions always produce boolean results.  */
>>> -      TREE_TYPE (expr) = boolean_type_node;
>>> +      if (TREE_CODE (type) != BOOLEAN_TYPE)
>>> +       TREE_TYPE (expr) = boolean_type_node;
>>>       return expr;
>>>
>>>     default:
>>> +      if (COMPARISON_CLASS_P (expr))
>>> +       {
>>> +         /* There expressions always prduce boolean results.  */
>>> +         if (TREE_CODE (type) != BOOLEAN_TYPE)
>>> +           TREE_TYPE (expr) = boolean_type_node;
>>> +         return expr;
>>> +       }
>>>       /* Other expressions that get here must have boolean values, but
>>>         might need to be converted to the appropriate mode.  */
>>> -      if (type == boolean_type_node)
>>> +      if (TREE_CODE (type) == BOOLEAN_TYPE)
>>>        return expr;
>>>       return fold_convert_loc (loc, boolean_type_node, expr);
>>>     }
>>> @@ -6763,7 +6768,7 @@ gimplify_expr (tree *expr_p, gimple_seq
>>>            tree org_type = TREE_TYPE (*expr_p);
>>>
>>>            *expr_p = gimple_boolify (*expr_p);
>>> -           if (org_type != boolean_type_node)
>>> +           if (!useless_type_conversion_p (org_type, TREE_TYPE (*expr_p)))
>>>              {
>>>                *expr_p = fold_convert (org_type, *expr_p);
>>
>> Use fold_convert_loc with saved_location
>
> Oh, good catch. Yes, I will adjust that.
>
>>>                ret = GS_OK;
>>> @@ -7208,7 +7213,7 @@ gimplify_expr (tree *expr_p, gimple_seq
>>>               fold_truth_not_expr) happily uses operand type and doesn't
>>>               automatically uses boolean_type as result, we need to keep
>>>               orignal type.  */
>>> -           if (org_type != boolean_type_node)
>>> +           if (!useless_type_conversion_p (org_type, TREE_TYPE (*expr_p)))
>>>              {
>>>                *expr_p = fold_convert (org_type, *expr_p);
>>
>> Likewise.  Maybe this fixes the diagnostic regression.
>>
>>>                ret = GS_OK;
>>> @@ -7288,7 +7293,19 @@ gimplify_expr (tree *expr_p, gimple_seq
>>>                  tree type = TREE_TYPE (TREE_OPERAND (*expr_p, 1));
>>>
>>>                  if (!AGGREGATE_TYPE_P (type))
>>> -                   goto expr_2;
>>> +                   {
>>> +                     tree org_type = TREE_TYPE (*expr_p);
>>> +                     *expr_p = gimple_boolify (*expr_p);
>>> +                     if (!useless_type_conversion_p (org_type,
>>> +                                                     TREE_TYPE (*expr_p)))
>>> +                       {
>>> +                         *expr_p = fold_convert_loc (saved_location,
>>> +                                                     org_type, *expr_p);
>>> +                         ret = GS_OK;
>>> +                       }
>>> +                     else
>>> +                       goto expr_2;
>>> +                   }
>>>                  else if (TYPE_MODE (type) != BLKmode)
>>>                    ret = gimplify_scalar_mode_aggregate_compare (expr_p);
>>>                  else
>>> Index: gcc-head/gcc/tree-cfg.c
>>> ===================================================================
>>> --- gcc-head.orig/gcc/tree-cfg.c
>>> +++ gcc-head/gcc/tree-cfg.c
>>> @@ -3203,7 +3203,9 @@ verify_gimple_comparison (tree type, tre
>>>        && (!POINTER_TYPE_P (op0_type)
>>>           || !POINTER_TYPE_P (op1_type)
>>>           || TYPE_MODE (op0_type) != TYPE_MODE (op1_type)))
>>> -      || !INTEGRAL_TYPE_P (type))
>>> +      || !INTEGRAL_TYPE_P (type)
>>> +      || (TREE_CODE (type) != BOOLEAN_TYPE
>>> +         && TYPE_PRECISION (type) != 1))
>>>     {
>>>       error ("type mismatch in comparison expression");
>>>       debug_generic_expr (type);
>>> Index: gcc-head/gcc/tree-ssa.c
>>> ===================================================================
>>> --- gcc-head.orig/gcc/tree-ssa.c
>>> +++ gcc-head/gcc/tree-ssa.c
>>> @@ -1306,10 +1306,10 @@ useless_type_conversion_p (tree outer_ty
>>>          || TYPE_PRECISION (inner_type) != TYPE_PRECISION (outer_type))
>>>        return false;
>>>
>>> -      /* Preserve conversions to BOOLEAN_TYPE if it is not of precision
>>> -         one.  */
>>> -      if (TREE_CODE (inner_type) != BOOLEAN_TYPE
>>> -         && TREE_CODE (outer_type) == BOOLEAN_TYPE
>>> +      /* Preserve conversions to/from BOOLEAN_TYPE if types are not
>>> +        of precision one.  */
>>> +      if (((TREE_CODE (inner_type) == BOOLEAN_TYPE)
>>> +          != (TREE_CODE (outer_type) == BOOLEAN_TYPE))
>>>          && TYPE_PRECISION (outer_type) != 1)
>>>        return false;
>>>
>>> Index: gcc-head/gcc/testsuite/gcc.dg/tree-ssa/builtin-expect-5.c
>>> ===================================================================
>>> --- gcc-head.orig/gcc/testsuite/gcc.dg/tree-ssa/builtin-expect-5.c
>>> +++ gcc-head/gcc/testsuite/gcc.dg/tree-ssa/builtin-expect-5.c
>>> @@ -11,5 +11,5 @@ f (int i, float j)
>>>
>>>  /* { 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-not {builtin_expect[^\n]*,
>>> 1\);\n[^\n]*if} "forwprop1"} } */
>>
>> Hm?  Why that?
>>
>>>  /* { dg-final { cleanup-tree-dump "forwprop?" } } */
>>> Index: gcc-head/gcc/testsuite/gcc.dg/tree-ssa/pr21031.c
>>> ===================================================================
>>> --- gcc-head.orig/gcc/testsuite/gcc.dg/tree-ssa/pr21031.c
>>> +++ gcc-head/gcc/testsuite/gcc.dg/tree-ssa/pr21031.c
>>> @@ -16,5 +16,5 @@ foo (int a)
>>>     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-head/gcc/testsuite/gcc.dg/tree-ssa/pr30978.c
>>> ===================================================================
>>> --- gcc-head.orig/gcc/testsuite/gcc.dg/tree-ssa/pr30978.c
>>> +++ gcc-head/gcc/testsuite/gcc.dg/tree-ssa/pr30978.c
>>> @@ -10,5 +10,5 @@ int foo(int a)
>>>   return e;
>>>  }
>>>
>>> -/* { dg-final { scan-tree-dump "e_. = a_..D. > 0;" "optimized" } } */
>>> +/* { dg-final { scan-tree-dump " = a_..D. > 0;" "optimized" } } */
>>>  /* { dg-final { cleanup-tree-dump "optimized" } } */
>>> Index: gcc-head/gcc/testsuite/gcc.dg/tree-ssa/ssa-fre-6.c
>>> ===================================================================
>>> --- gcc-head.orig/gcc/testsuite/gcc.dg/tree-ssa/ssa-fre-6.c
>>> +++ gcc-head/gcc/testsuite/gcc.dg/tree-ssa/ssa-fre-6.c
>>> @@ -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" } } */
>>> Index: gcc-head/gcc/tree-ssa-forwprop.c
>>> ===================================================================
>>> --- gcc-head.orig/gcc/tree-ssa-forwprop.c
>>> +++ gcc-head/gcc/tree-ssa-forwprop.c
>>> @@ -367,9 +367,61 @@ combine_cond_expr_cond (location_t loc,
>>>   gcc_assert (TREE_CODE_CLASS (code) == tcc_comparison);
>>>
>>>   t = fold_binary_loc (loc, code, type, op0, op1);
>>> +
>>> +  if (!t && INTEGRAL_TYPE_P (TREE_TYPE (op1))
>>> +      && TYPE_PRECISION (TREE_TYPE (op1)) == 1
>>> +      && (code == EQ_EXPR || code == NE_EXPR))
>>> +    {
>>> +      if (TREE_CODE (op1) == INTEGER_CST)
>>> +        {
>>> +         if (integer_onep (op1))
>>> +           {
>>> +             op1 = fold_convert_loc (loc, TREE_TYPE (op1), integer_zero_node);
>>> +             code = (code == NE_EXPR ? EQ_EXPR : NE_EXPR);
>>
>> So you change truthvalue !=/== 1 to truthvalue ==/!= 0 and then
>> recurse ... that doesn't make sense to me and is super-ugly.
>> What's the testcase that made you add all this code?
>
> Well, the convert from truthvalue !=/== 1 to !=/== 0 limits the amount
> of cases to handle. As for truthvalued X the we have then just to
> handle two cases. X != 0 -> X, and X == 0 -> (X ^ 1).
> The recursion is someting I saw as existing pattern (for the same
> thing) in truth-op folding in fold-const.
>
> Actual I can remove this optimization here, as it should be convered
> by VRP already (when VRP handles 1-bit precision bitwise ops proper).

We should have a canonical form for those compares and change
them accordingly, best in fold_stmt.

Richard.