> Am 09.03.2024 um 09:28 schrieb Jakub Jelinek <ja...@redhat.com>:
>
> Hi!
>
> The following testcase ICEs, because update-address-taken subpass of
> fre5 rewrites
> _BitInt(128) b;
> vector(16) unsigned char _3;
>
> <bb 2> [local count: 1073741824]:
> _3 = MEM <vector(16) unsigned char> [(char * {ref-all})p_2(D)];
> MEM <vector(16) unsigned char> [(char * {ref-all})&b] = _3;
> b ={v} {CLOBBER(eos)};
> to
> _BitInt(128) b;
> vector(16) unsigned char _3;
>
> <bb 2> [local count: 1073741824]:
> _3 = MEM <vector(16) unsigned char> [(char * {ref-all})p_2(D)];
> b_5 = VIEW_CONVERT_EXPR<_BitInt(128)>(_3);
> but we can't have large/huge _BitInt vars in SSA form after the bitint
> lowering except for function arguments loaded from memory, as expansion
> isn't able to deal with those, it relies on bitint lowering to lower
> those operations.
> The following patch fixes that by not clearing TREE_ADDRESSABLE for
> large/huge _BitInt vars after bitint lowering, such that we don't
> rewrite them into SSA form.
>
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
>
Ideally we’d clear TREE_ADDRESSABLE but set DECL_NOT_GIMPLE_REG, I think the
analysis where we check the base would be a more appropriate place to enforce
that.
Richard
> 2024-03-09 Jakub Jelinek <ja...@redhat.com>
>
> PR tree-optimization/114278
> * tree-ssa.cc (maybe_optimize_var): Punt on large/huge _BitInt
> vars after bitint lowering.
>
> * gcc.dg/bitint-99.c: New test.
>
> --- gcc/tree-ssa.cc.jj 2024-01-03 11:51:39.902615009 +0100
> +++ gcc/tree-ssa.cc 2024-03-08 14:24:11.844821915 +0100
> @@ -1753,7 +1753,11 @@ maybe_optimize_var (tree var, bitmap add
> /* Global Variables, result decls cannot be changed. */
> if (is_global_var (var)
> || TREE_CODE (var) == RESULT_DECL
> - || bitmap_bit_p (addresses_taken, DECL_UID (var)))
> + || bitmap_bit_p (addresses_taken, DECL_UID (var))
> + || (TREE_CODE (TREE_TYPE (var)) == BITINT_TYPE
> + /* Don't change large/huge _BitInt vars after _BitInt lowering. */
> + && (cfun->curr_properties & PROP_gimple_lbitint) != 0
> + && TYPE_PRECISION (TREE_TYPE (var)) > MAX_FIXED_MODE_SIZE))
> return;
>
> bool maybe_reg = false;
> --- gcc/testsuite/gcc.dg/bitint-99.c.jj 2024-03-08 14:26:17.658069942 +0100
> +++ gcc/testsuite/gcc.dg/bitint-99.c 2024-03-08 14:25:36.292645965 +0100
> @@ -0,0 +1,26 @@
> +/* PR tree-optimization/114278 */
> +/* { dg-do compile { target bitint } } */
> +/* { dg-options "-O2 -fno-tree-dce -fno-tree-dse -fno-tree-ccp" } */
> +/* { dg-additional-options "-mavx2" { target i?86-*-* x86_64-*-* } } */
> +
> +void
> +foo (void *p)
> +{
> + _BitInt(64) b = *(_BitInt(64) *) __builtin_memmove (&b, p, sizeof
> (_BitInt(64)));
> +}
> +
> +#if __BITINT_MAXWIDTH__ >= 128
> +void
> +bar (void *p)
> +{
> + _BitInt(128) b = *(_BitInt(128) *) __builtin_memmove (&b, p, sizeof
> (_BitInt(128)));
> +}
> +#endif
> +
> +#if __BITINT_MAXWIDTH__ >= 256
> +void
> +baz (void *p)
> +{
> + _BitInt(256) b = *(_BitInt(256) *) __builtin_memmove (&b, p, sizeof
> (_BitInt(256)));
> +}
> +#endif
>
> Jakub
>
