On Wed, 14 Sep 2022, Jakub Jelinek wrote:
> Hi!
>
> My change to match.pd (that added the two simplifications this patch
> touches) results in more |/^/& assignments with pointer arguments,
> but since r12-1608 we reject pointer operands for BIT_NOT_EXPR.
>
> Disallowing them for BIT_NOT_EXPR and allowing for BIT_{IOR,XOR,AND}_EXPR
> leads to a match.pd maintainance nightmare (see one of the patches in the
> PR), so either we want to allow pointer operand on BIT_NOT_EXPR (but then
> we run into issues e.g. with the ranger which expects it can emulate
> BIT_NOT_EXPR ~X as - 1 - X which doesn't work for pointers which don't
> support MINUS_EXPR), or the following patch disallows pointer arguments
> for all of BIT_{IOR,XOR,AND}_EXPR with the exception of BIT_AND_EXPR
> with INTEGER_CST last operand (for simpler pointer realignment).
> I had to tweak one reassoc optimization and the two match.pd
> simplifications.
>
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
OK.
Did you check what breaks when we reverse the decision to allow
BIT_AND_EXPR to align pointers alltogether? I think we don't
have any
(T')(((T)ptr) & CST) -> ptr & CST
folding at least. But I guess some passes that build pointer
re-alignments might need adjustment.
> P.S.: I know it would be better for the verifiers to have positive
> set of types it wants to allow for each operation, but I have no idea
> what exactly we use there right now.
I think for BIT_*_EXPR we want ANY_INTEGRAL_TYPE_P (well, likely
not complex int, but ...). So if a patch to check that passes
bootstrap that would be nice to have.
Richard.
> 2022-09-14 Jakub Jelinek <ja...@redhat.com>
>
> PR tree-optimization/106878
> * tree-cfg.cc (verify_gimple_assign_binary): Disallow pointer,
> reference or OFFSET_TYPE BIT_IOR_EXPR, BIT_XOR_EXPR or, unless
> the second argument is INTEGER_CST, BIT_AND_EXPR.
> * match.pd ((type) X op CST -> (type) (X op ((type-x) CST)),
> (type) (((type2) X) op Y) -> (X op (type) Y)): Punt for
> POINTER_TYPE_P or OFFSET_TYPE.
> * tree-ssa-reassoc.cc (optimize_range_tests_cmp_bitwise): For
> pointers cast them to pointer sized integers first.
>
> * gcc.c-torture/compile/pr106878.c: New test.
>
> --- gcc/tree-cfg.cc.jj 2022-09-08 20:22:07.788184491 +0200
> +++ gcc/tree-cfg.cc 2022-09-13 09:28:53.563243962 +0200
> @@ -4167,6 +4167,8 @@ verify_gimple_assign_binary (gassign *st
> case ROUND_MOD_EXPR:
> case RDIV_EXPR:
> case EXACT_DIV_EXPR:
> + case BIT_IOR_EXPR:
> + case BIT_XOR_EXPR:
> /* Disallow pointer and offset types for many of the binary gimple. */
> if (POINTER_TYPE_P (lhs_type)
> || TREE_CODE (lhs_type) == OFFSET_TYPE)
> @@ -4182,9 +4184,23 @@ verify_gimple_assign_binary (gassign *st
>
> case MIN_EXPR:
> case MAX_EXPR:
> - case BIT_IOR_EXPR:
> - case BIT_XOR_EXPR:
> + /* Continue with generic binary expression handling. */
> + break;
> +
> case BIT_AND_EXPR:
> + if (POINTER_TYPE_P (lhs_type)
> + && TREE_CODE (rhs2) == INTEGER_CST)
> + break;
> + /* Disallow pointer and offset types for many of the binary gimple. */
> + if (POINTER_TYPE_P (lhs_type)
> + || TREE_CODE (lhs_type) == OFFSET_TYPE)
> + {
> + error ("invalid types for %qs", code_name);
> + debug_generic_expr (lhs_type);
> + debug_generic_expr (rhs1_type);
> + debug_generic_expr (rhs2_type);
> + return true;
> + }
> /* Continue with generic binary expression handling. */
> break;
>
> --- gcc/match.pd.jj 2022-09-08 20:22:00.836276502 +0200
> +++ gcc/match.pd 2022-09-13 10:21:04.567853941 +0200
> @@ -1763,6 +1763,8 @@ (define_operator_list SYNC_FETCH_AND_AND
> && (int_fits_type_p (@1, TREE_TYPE (@0))
> || tree_nop_conversion_p (TREE_TYPE (@0), type)))
> || types_match (@0, @1))
> + && !POINTER_TYPE_P (TREE_TYPE (@0))
> + && TREE_CODE (TREE_TYPE (@0)) != OFFSET_TYPE
> /* ??? This transform conflicts with fold-const.cc doing
> Convert (T)(x & c) into (T)x & (T)c, if c is an integer
> constants (if x has signed type, the sign bit cannot be set
> @@ -1799,7 +1801,9 @@ (define_operator_list SYNC_FETCH_AND_AND
> (if (GIMPLE
> && TREE_CODE (@1) != INTEGER_CST
> && tree_nop_conversion_p (type, TREE_TYPE (@2))
> - && types_match (type, @0))
> + && types_match (type, @0)
> + && !POINTER_TYPE_P (TREE_TYPE (@0))
> + && TREE_CODE (TREE_TYPE (@0)) != OFFSET_TYPE)
> (bitop @0 (convert @1)))))
>
> (for bitop (bit_and bit_ior)
> --- gcc/tree-ssa-reassoc.cc.jj 2022-06-28 13:03:31.292684917 +0200
> +++ gcc/tree-ssa-reassoc.cc 2022-09-13 10:18:27.466085947 +0200
> @@ -3608,10 +3608,14 @@ optimize_range_tests_cmp_bitwise (enum t
> tree type2 = NULL_TREE;
> bool strict_overflow_p = false;
> candidates.truncate (0);
> + if (POINTER_TYPE_P (type1))
> + type1 = pointer_sized_int_node;
> for (j = i; j; j = chains[j - 1])
> {
> tree type = TREE_TYPE (ranges[j - 1].exp);
> strict_overflow_p |= ranges[j - 1].strict_overflow_p;
> + if (POINTER_TYPE_P (type))
> + type = pointer_sized_int_node;
> if ((b % 4) == 3)
> {
> /* For the signed < 0 cases, the types should be
> @@ -3642,6 +3646,8 @@ optimize_range_tests_cmp_bitwise (enum t
> tree type = TREE_TYPE (ranges[j - 1].exp);
> if (j == k)
> continue;
> + if (POINTER_TYPE_P (type))
> + type = pointer_sized_int_node;
> if ((b % 4) == 3)
> {
> if (!useless_type_conversion_p (type1, type))
> @@ -3671,7 +3677,7 @@ optimize_range_tests_cmp_bitwise (enum t
> op = r->exp;
> continue;
> }
> - if (id == l)
> + if (id == l || POINTER_TYPE_P (TREE_TYPE (op)))
> {
> code = (b % 4) == 3 ? BIT_NOT_EXPR : NOP_EXPR;
> g = gimple_build_assign (make_ssa_name (type1), code, op);
> @@ -3695,6 +3701,14 @@ optimize_range_tests_cmp_bitwise (enum t
> gimple_seq_add_stmt_without_update (&seq, g);
> op = gimple_assign_lhs (g);
> }
> + type1 = TREE_TYPE (ranges[k - 1].exp);
> + if (POINTER_TYPE_P (type1))
> + {
> + gimple *g
> + = gimple_build_assign (make_ssa_name (type1), NOP_EXPR, op);
> + gimple_seq_add_stmt_without_update (&seq, g);
> + op = gimple_assign_lhs (g);
> + }
> candidates.pop ();
> if (update_range_test (&ranges[k - 1], NULL, candidates.address (),
> candidates.length (), opcode, ops, op,
> --- gcc/testsuite/gcc.c-torture/compile/pr106878.c.jj 2022-09-13
> 10:21:04.567853941 +0200
> +++ gcc/testsuite/gcc.c-torture/compile/pr106878.c 2022-09-13
> 10:21:04.567853941 +0200
> @@ -0,0 +1,15 @@
> +/* PR tree-optimization/106878 */
> +
> +typedef __INTPTR_TYPE__ intptr_t;
> +typedef __UINTPTR_TYPE__ uintptr_t;
> +int a;
> +
> +int
> +foo (const int *c)
> +{
> + uintptr_t d = ((intptr_t) c | (intptr_t) &a) & 65535 << 16;
> + intptr_t e = (intptr_t) c;
> + if (d != (e & 65535 << 16))
> + return 1;
> + return 0;
> +}
>
> Jakub
>
>
--
Richard Biener <rguent...@suse.de>
SUSE Software Solutions Germany GmbH, Frankenstrasse 146, 90461 Nuernberg,
Germany; GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman;
HRB 36809 (AG Nuernberg)
