On Mon, 31 Jul 2023 at 22:39, Andrew Pinski via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
>
> This is a new version of the patch.
> Instead of doing the matching of inversion comparison directly inside
> match, creating a new function (bitwise_inverted_equal_p) to do it.
> It is very similar to bitwise_equal_p that was added in
> r14-2751-g2a3556376c69a1fb
> but instead it says `expr1 == ~expr2`. A follow on patch, will
> use this function in other patterns where we try to match `@0` and `(bit_not
> @0)`.
>
> Changed the name bitwise_not_equal_p to bitwise_inverted_equal_p.
>
> Committed as approved after a Bootstrapped and test on x86_64-linux-gnu with
> no regressions.
Hi Andrew,
Unfortunately, this patch (committed in
2bae476b511dc441bf61da8a49cca655575e7dd6) causes
segmentation fault for pr33133.c on aarch64-linux-gnu because of
infinite recursion.
Running the test under gdb shows:
Program received signal SIGSEGV, Segmentation fault.
operand_compare::operand_equal_p (this=0x29dc680
<default_compare_instance>, arg0=0xfffff7789a68, arg1=0xfffff7789f30,
flags=16) at ../../gcc/gcc/fold-const.cc:3088
3088 {
(gdb) bt
#0 operand_compare::operand_equal_p (this=0x29dc680
<default_compare_instance>, arg0=0xfffff7789a68, arg1=0xfffff7789f30,
flags=16) at ../../gcc/gcc/fold-const.cc:3088
#1 0x0000000000a90394 in operand_compare::verify_hash_value
(this=this@entry=0x29dc680 <default_compare_instance>,
arg0=arg0@entry=0xfffff7789a68, arg1=arg1@entry=0xfffff7789f30,
flags=flags@entry=0, ret=ret@entry=0xfffffc000157)
at ../../gcc/gcc/fold-const.cc:4074
#2 0x0000000000a9351c in operand_compare::verify_hash_value
(ret=0xfffffc000157, flags=0, arg1=0xfffff7789f30,
arg0=0xfffff7789a68, this=0x29dc680 <default_compare_instance>) at
../../gcc/gcc/fold-const.cc:4072
#3 operand_compare::operand_equal_p (this=this@entry=0x29dc680
<default_compare_instance>, arg0=arg0@entry=0xfffff7789a68,
arg1=arg1@entry=0xfffff7789f30, flags=flags@entry=0) at
../../gcc/gcc/fold-const.cc:3090
#4 0x0000000000a9791c in operand_equal_p
(arg0=arg0@entry=0xfffff7789a68, arg1=arg1@entry=0xfffff7789f30,
flags=flags@entry=0) at ../../gcc/gcc/fold-const.cc:4105
#5 0x0000000001d38dd0 in gimple_bitwise_inverted_equal_p
(expr1=0xfffff7789a68, expr2=0xfffff7789f30, valueize=
0x112d698 <rpo_vn_valueize(tree_node*)>) at
../../gcc/gcc/gimple-match-head.cc:284
#6 0x0000000001d38e80 in gimple_bitwise_inverted_equal_p
(expr1=0xfffff7789a68, expr2=0xfffff77d0240,
valueize=0x112d698 <rpo_vn_valueize(tree_node*)>) at
../../gcc/gcc/gimple-match-head.cc:296
#7 0x0000000001d38e80 in gimple_bitwise_inverted_equal_p
(expr1=0xfffff7789a68, expr2=0xfffff7789f30,
valueize=0x112d698 <rpo_vn_valueize(tree_node*)>) at
../../gcc/gcc/gimple-match-head.cc:296
#8 0x0000000001d38e80 in gimple_bitwise_inverted_equal_p
(expr1=0xfffff7789a68, expr2=0xfffff77d0240,
...
It seems to recurse cyclically with expr2=0xfffff7789f30 ->
expr2=0xfffff77d0240 eventually leading to segfault.
while expr1=0xfffff7789a68 remains same throughout the stack frames.
Thanks,
Prathamesh
>
> PR tree-optimization/100864
>
> gcc/ChangeLog:
>
> * generic-match-head.cc (bitwise_inverted_equal_p): New function.
> * gimple-match-head.cc (bitwise_inverted_equal_p): New macro.
> (gimple_bitwise_inverted_equal_p): New function.
> * match.pd ((~x | y) & x): Use bitwise_inverted_equal_p
> instead of direct matching bit_not.
>
> gcc/testsuite/ChangeLog:
>
> * gcc.dg/tree-ssa/bitops-3.c: New test.
> ---
> gcc/generic-match-head.cc | 42 ++++++++++++++
> gcc/gimple-match-head.cc | 71 ++++++++++++++++++++++++
> gcc/match.pd | 5 +-
> gcc/testsuite/gcc.dg/tree-ssa/bitops-3.c | 67 ++++++++++++++++++++++
> 4 files changed, 183 insertions(+), 2 deletions(-)
> create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/bitops-3.c
>
> diff --git a/gcc/generic-match-head.cc b/gcc/generic-match-head.cc
> index a71c0727b0b..ddaf22f2179 100644
> --- a/gcc/generic-match-head.cc
> +++ b/gcc/generic-match-head.cc
> @@ -121,3 +121,45 @@ bitwise_equal_p (tree expr1, tree expr2)
> return wi::to_wide (expr1) == wi::to_wide (expr2);
> return operand_equal_p (expr1, expr2, 0);
> }
> +
> +/* Return true if EXPR1 and EXPR2 have the bitwise opposite value,
> + but not necessarily same type.
> + The types can differ through nop conversions. */
> +
> +static inline bool
> +bitwise_inverted_equal_p (tree expr1, tree expr2)
> +{
> + STRIP_NOPS (expr1);
> + STRIP_NOPS (expr2);
> + if (expr1 == expr2)
> + return false;
> + if (!tree_nop_conversion_p (TREE_TYPE (expr1), TREE_TYPE (expr2)))
> + return false;
> + if (TREE_CODE (expr1) == INTEGER_CST && TREE_CODE (expr2) == INTEGER_CST)
> + return wi::to_wide (expr1) == ~wi::to_wide (expr2);
> + if (operand_equal_p (expr1, expr2, 0))
> + return false;
> + if (TREE_CODE (expr1) == BIT_NOT_EXPR
> + && bitwise_equal_p (TREE_OPERAND (expr1, 0), expr2))
> + return true;
> + if (TREE_CODE (expr2) == BIT_NOT_EXPR
> + && bitwise_equal_p (expr1, TREE_OPERAND (expr2, 0)))
> + return true;
> + if (COMPARISON_CLASS_P (expr1)
> + && COMPARISON_CLASS_P (expr2))
> + {
> + tree op10 = TREE_OPERAND (expr1, 0);
> + tree op20 = TREE_OPERAND (expr2, 0);
> + if (!operand_equal_p (op10, op20))
> + return false;
> + tree op11 = TREE_OPERAND (expr1, 1);
> + tree op21 = TREE_OPERAND (expr2, 1);
> + if (!operand_equal_p (op11, op21))
> + return false;
> + if (invert_tree_comparison (TREE_CODE (expr1),
> + HONOR_NANS (op10))
> + == TREE_CODE (expr2))
> + return true;
> + }
> + return false;
> +}
> diff --git a/gcc/gimple-match-head.cc b/gcc/gimple-match-head.cc
> index 5d6d26d009b..0265e55be93 100644
> --- a/gcc/gimple-match-head.cc
> +++ b/gcc/gimple-match-head.cc
> @@ -263,3 +263,74 @@ gimple_bitwise_equal_p (tree expr1, tree expr2, tree
> (*valueize) (tree))
> return true;
> return false;
> }
> +
> +/* Return true if EXPR1 and EXPR2 have the bitwise opposite value,
> + but not necessarily same type.
> + The types can differ through nop conversions. */
> +#define bitwise_inverted_equal_p(expr1, expr2) \
> + gimple_bitwise_inverted_equal_p (expr1, expr2, valueize)
> +
> +/* Helper function for bitwise_equal_p macro. */
> +
> +static inline bool
> +gimple_bitwise_inverted_equal_p (tree expr1, tree expr2, tree (*valueize)
> (tree))
> +{
> + if (expr1 == expr2)
> + return false;
> + if (!tree_nop_conversion_p (TREE_TYPE (expr1), TREE_TYPE (expr2)))
> + return false;
> + if (TREE_CODE (expr1) == INTEGER_CST && TREE_CODE (expr2) == INTEGER_CST)
> + return wi::to_wide (expr1) == ~wi::to_wide (expr2);
> + if (operand_equal_p (expr1, expr2, 0))
> + return false;
> +
> + tree other;
> + if (gimple_nop_convert (expr1, &other, valueize)
> + && gimple_bitwise_inverted_equal_p (other, expr2, valueize))
> + return true;
> +
> + if (gimple_nop_convert (expr2, &other, valueize)
> + && gimple_bitwise_inverted_equal_p (expr1, other, valueize))
> + return true;
> +
> + if (TREE_CODE (expr1) != SSA_NAME
> + || TREE_CODE (expr2) != SSA_NAME)
> + return false;
> +
> + gimple *d1 = get_def (valueize, expr1);
> + gassign *a1 = safe_dyn_cast <gassign *> (d1);
> + gimple *d2 = get_def (valueize, expr2);
> + gassign *a2 = safe_dyn_cast <gassign *> (d2);
> + if (a1
> + && gimple_assign_rhs_code (a1) == BIT_NOT_EXPR
> + && gimple_bitwise_equal_p (do_valueize (valueize,
> + gimple_assign_rhs1 (a1)),
> + expr2, valueize))
> + return true;
> + if (a2
> + && gimple_assign_rhs_code (a2) == BIT_NOT_EXPR
> + && gimple_bitwise_equal_p (expr1,
> + do_valueize (valueize,
> + gimple_assign_rhs1 (a2)),
> + valueize))
> + return true;
> +
> + if (a1 && a2
> + && TREE_CODE_CLASS (gimple_assign_rhs_code (a1)) == tcc_comparison
> + && TREE_CODE_CLASS (gimple_assign_rhs_code (a2)) == tcc_comparison)
> + {
> + tree op10 = gimple_assign_rhs1 (a1);
> + tree op20 = gimple_assign_rhs1 (a2);
> + if (!operand_equal_p (op10, op20))
> + return false;
> + tree op11 = gimple_assign_rhs2 (a1);
> + tree op21 = gimple_assign_rhs2 (a2);
> + if (!operand_equal_p (op11, op21))
> + return false;
> + if (invert_tree_comparison (gimple_assign_rhs_code (a1),
> + HONOR_NANS (op10))
> + == gimple_assign_rhs_code (a2))
> + return true;
> + }
> + return false;
> +}
> diff --git a/gcc/match.pd b/gcc/match.pd
> index ee6cef6b09d..5fc6f517ab9 100644
> --- a/gcc/match.pd
> +++ b/gcc/match.pd
> @@ -1943,8 +1943,9 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
> /* (~x | y) & x -> x & y */
> /* (~x & y) | x -> x | y */
> (simplify
> - (bitop:c (rbitop:c (bit_not @0) @1) @0)
> - (bitop @0 @1)))
> + (bitop:c (rbitop:c @2 @1) @0)
> + (if (bitwise_inverted_equal_p (@0, @2))
> + (bitop @0 @1))))
>
> /* ((x | y) & z) | x -> (z & y) | x */
> (simplify
> diff --git a/gcc/testsuite/gcc.dg/tree-ssa/bitops-3.c
> b/gcc/testsuite/gcc.dg/tree-ssa/bitops-3.c
> new file mode 100644
> index 00000000000..bf11a129b69
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/tree-ssa/bitops-3.c
> @@ -0,0 +1,67 @@
> +/* PR tree-optimization/100864 */
> +
> +/* { dg-do run } */
> +/* { dg-options "-O1 -fdump-tree-optimized-raw" } */
> +
> +#define op_ne !=
> +#define op_eq ==
> +#define op_lt <
> +#define op_le <=
> +#define op_gt >
> +#define op_ge >=
> +
> +#define operators(t) \
> +t(ne) \
> +t(eq) \
> +t(lt) \
> +t(le) \
> +t(gt) \
> +t(ge)
> +
> +#define cmpfunc(v, op) \
> +__attribute__((noipa)) \
> +_Bool func_##op##_##v(v int a, v int b, v _Bool e) \
> +{ \
> + v _Bool c = (a op_##op b); \
> + v _Bool d = !c; \
> + return (e & d) | c; \
> +}
> +
> +#define cmp_funcs(op) \
> +cmpfunc(, op) \
> +cmpfunc(volatile , op)
> +
> +operators(cmp_funcs)
> +
> +#define test(op) \
> +if (func_##op##_ (a, b, e) != func_##op##_volatile (a, b, e)) \
> + __builtin_abort();
> +
> +int main()
> +{
> + for(int a = -3; a <= 3; a++)
> + for(int b = -3; b <= 3; b++)
> + {
> + _Bool e = 0;
> + operators(test)
> + e = 1;
> + operators(test)
> + }
> + return 0;
> +}
> +
> +/* Check to make sure we optimize `(a&!b) | b` -> `a | b`. */
> +/* There are 6 different comparison operators testing here. */
> +/* bit_not_expr and bit_and_expr should show up for each one (volatile). */
> +/* Each operator should show up twice
> + (except for `!=` which shows up 2*6 (each tester) + 2 (the 2 loops) extra
> = 16). */
> +/* bit_ior_expr will show up for each operator twice (non-volatile and
> volatile). */
> +/* { dg-final { scan-tree-dump-times "ne_expr," 16 "optimized"} } */
> +/* { dg-final { scan-tree-dump-times "eq_expr," 2 "optimized"} } */
> +/* { dg-final { scan-tree-dump-times "lt_expr," 2 "optimized"} } */
> +/* { dg-final { scan-tree-dump-times "le_expr," 2 "optimized"} } */
> +/* { dg-final { scan-tree-dump-times "gt_expr," 2 "optimized"} } */
> +/* { dg-final { scan-tree-dump-times "ge_expr," 2 "optimized"} } */
> +/* { dg-final { scan-tree-dump-times "bit_not_expr," 6 "optimized"} } */
> +/* { dg-final { scan-tree-dump-times "bit_and_expr," 6 "optimized"} } */
> +/* { dg-final { scan-tree-dump-times "bit_ior_expr," 12 "optimized"} } */
> --
> 2.31.1
>
