> Am 02.01.2025 um 10:36 schrieb Jakub Jelinek <ja...@redhat.com>:
>
> Hi!
>
> In order to stress test RAW_DATA_CST handling, I've tested trunk gcc with
> r15-6339 reapplied and a hack where I've changed
> const unsigned int raw_data_min_len = 128;
> to
> const unsigned int raw_data_min_len = 2;
> in cp_lexer_new_main and 64 to 4 several times in c_parser_initval
> and c_maybe_optimize_large_byte_initializer, so that RAW_DATA_CST doesn't
> trigger just on very large initializers, but even quite small ones.
>
> One of the regressions (will work on the others next) was that pr90838.c
> testcase regressed, check_ctz_array needs to handle RAW_DATA_CST, otherwise
> on larger initializers or if those come from #embed just won't trigger.
> The new testcase shows when it doesn't trigger anymore (regression from 14).
>
> The patch just handles RAW_DATA_CST in the CONSTRUCTOR_ELTS the same as is
> it was a series of INTEGER_CSTs.
>
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
Ok
Richard
> 2025-01-02 Jakub Jelinek <ja...@redhat.com>
>
> * tree-ssa-forwprop.cc (check_ctz_array): Handle also RAW_DATA_CST
> in the CONSTRUCTOR_ELTS.
>
> * gcc.dg/pr90838-2.c: New test.
>
> --- gcc/tree-ssa-forwprop.cc.jj 2024-12-28 00:12:11.185146287 +0100
> +++ gcc/tree-ssa-forwprop.cc 2024-12-31 12:45:33.512434253 +0100
> @@ -2269,7 +2269,7 @@ check_ctz_array (tree ctor, unsigned HOS
> HOST_WIDE_INT &zero_val, unsigned shift, unsigned bits)
> {
> tree elt, idx;
> - unsigned HOST_WIDE_INT i, mask;
> + unsigned HOST_WIDE_INT i, mask, raw_idx = 0;
> unsigned matched = 0;
>
> mask = ((HOST_WIDE_INT_1U << (bits - shift)) - 1) << shift;
> @@ -2278,13 +2278,34 @@ check_ctz_array (tree ctor, unsigned HOS
>
> FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (ctor), i, idx, elt)
> {
> - if (TREE_CODE (idx) != INTEGER_CST || TREE_CODE (elt) != INTEGER_CST)
> + if (TREE_CODE (idx) != INTEGER_CST)
> return false;
> - if (i > bits * 2)
> + if (TREE_CODE (elt) != INTEGER_CST && TREE_CODE (elt) != RAW_DATA_CST)
> return false;
>
> unsigned HOST_WIDE_INT index = tree_to_shwi (idx);
> - HOST_WIDE_INT val = tree_to_shwi (elt);
> + HOST_WIDE_INT val;
> +
> + if (TREE_CODE (elt) == INTEGER_CST)
> + val = tree_to_shwi (elt);
> + else
> + {
> + if (raw_idx == (unsigned) RAW_DATA_LENGTH (elt))
> + {
> + raw_idx = 0;
> + continue;
> + }
> + if (TYPE_UNSIGNED (TREE_TYPE (elt)))
> + val = RAW_DATA_UCHAR_ELT (elt, raw_idx);
> + else
> + val = RAW_DATA_SCHAR_ELT (elt, raw_idx);
> + index += raw_idx;
> + raw_idx++;
> + i--;
> + }
> +
> + if (index > bits * 2)
> + return false;
>
> if (index == 0)
> {
> --- gcc/testsuite/gcc.dg/pr90838-2.c.jj 2024-12-31 12:50:10.548568029 +0100
> +++ gcc/testsuite/gcc.dg/pr90838-2.c 2024-12-31 12:52:41.944455198 +0100
> @@ -0,0 +1,39 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O2 -fdump-tree-forwprop2-details" } */
> +/* { dg-additional-options "-mbmi" { target { { i?86-*-* x86_64-*-* } && { !
> { ia32 } } } } } */
> +/* { dg-additional-options "-march=rv64gc_zbb" { target { rv64 } } } */
> +/* { dg-additional-options "-march=rv32gc_zbb" { target { rv32 } } } */
> +/* { dg-require-effective-target int32plus } */
> +
> +static const unsigned long long magic = 0x03f08c5392f756cdULL;
> +
> +static const char table[128] = {
> + 0, 1, 12, 2, 13, 22, 17, 3,
> + 14, 33, 23, 36, 18, 58, 28, 4,
> + 62, 15, 34, 26, 24, 48, 50, 37,
> + 19, 55, 59, 52, 29, 44, 39, 5,
> + 63, 11, 21, 16, 32, 35, 57, 27,
> + 61, 25, 47, 49, 54, 51, 43, 38,
> + 10, 20, 31, 56, 60, 46, 53, 42,
> + 9, 30, 45, 41, 8, 40, 7, 6,
> + 1, 2, 3, 4, 5, 6, 7, 8,
> + 9, 10, 11, 12, 13, 14, 15, 16,
> + 17, 18, 19, 20, 21, 22, 23, 24,
> + 25, 26, 27, 28, 29, 30, 31, 32,
> + 33, 34, 35, 36, 37, 38, 39, 40,
> + 41, 42, 43, 44, 45, 46, 47, 48,
> + 49, 50, 51, 52, 53, 54, 55, 56,
> + 57, 58, 59, 60, 61, 62, 63, 64
> +};
> +
> +int ctz4 (unsigned long x)
> +{
> + unsigned long lsb = x & -x;
> + return table[(lsb * magic) >> 58];
> +}
> +
> +/* { dg-final { scan-tree-dump {= \.CTZ} "forwprop2" { target { { i?86-*-*
> x86_64-*-* } && { ! { ia32 } } } } } } */
> +/* { dg-final { scan-tree-dump {= \.CTZ} "forwprop2" { target aarch64*-*-* }
> } } */
> +/* { dg-final { scan-tree-dump {= \.CTZ} "forwprop2" { target { rv64 } } } }
> */
> +/* { dg-final { scan-tree-dump {= \.CTZ} "forwprop2" { target { rv32 } } } }
> */
> +/* { dg-final { scan-tree-dump {= \.CTZ} "forwprop2" { target {
> loongarch64*-*-* } } } } */
>
> Jakub
>
