> Am 03.01.2025 um 09:44 schrieb Jakub Jelinek <ja...@redhat.com>:
>
> Hi!
>
> When touching the function yesterday, I was surprised to see just
> TREE_CODE (something) != INTEGER_CST checks followed by tree_to_shwi.
> That would ICE if the INTEGER_CST doesn't fit.
>
> I have actually not been able to reproduce an ICE for the elt case
> as the caller gives up if the precision of the array type is larger than 32
> bits (but I think it is still cleaner to use it), the idx case can actually
> ICE e.g. on
> static const unsigned long long magic = 0x03f08c5392f756cdULL;
> static const char table[] = {
> 0, [0x8000000000000000ULL] = 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,
> };
>
> int ctz (unsigned long x)
> {
> unsigned long lsb = x & -x;
> return table[(lsb * magic) >> 58];
> }
> ~/src/gcc/obj20/gcc/cc1 -quiet /tmp/1.c -O2 -mbmi
> /tmp/1.c:2:19: warning: size of ‘table’ 9223372036854775871 bytes exceeds
> maximum object size 9223372036854775807 [-Wlarger-than=]
> 2 | static const char table[] = {
> | ^~~~~
> during GIMPLE pass: forwprop
> /tmp/1.c: In function ‘ctz’:
> /tmp/1.c:13:1: internal compiler error: in tree_to_shwi, at tree.cc:6518
> 13 | }
> | ^
> 0x2efa51f internal_error(char const*, ...)
> ../../gcc/diagnostic-global-context.cc:517
> 0xf3c617 fancy_abort(char const*, int, char const*)
> ../../gcc/diagnostic.cc:1722
> 0x949a36 tree_to_shwi(tree_node const*)
> ../../gcc/tree.cc:6518
> 0x949a36 tree_to_shwi(tree_node const*)
> ../../gcc/tree.cc:6516
> 0x18472d5 check_ctz_array
> ../../gcc/tree-ssa-forwprop.cc:2286
> but given the 9223372036854775871 bytes long array
> I'm not sure it is appropriate for the testsuite.
>
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
Ok
> 2025-01-03 Jakub Jelinek <ja...@redhat.com>
>
> * tree-ssa-forwprop.cc (check_ctz_array): Use tree_fits_shwi_p instead
> of just TREE_CODE tests for INTEGER_CST.
>
> --- gcc/tree-ssa-forwprop.cc.jj 2025-01-02 12:29:23.906259521 +0100
> +++ gcc/tree-ssa-forwprop.cc 2025-01-02 13:54:25.077630882 +0100
> @@ -2278,9 +2278,9 @@ check_ctz_array (tree ctor, unsigned HOS
>
> FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (ctor), i, idx, elt)
> {
> - if (TREE_CODE (idx) != INTEGER_CST)
> + if (!tree_fits_shwi_p (idx))
> return false;
> - if (TREE_CODE (elt) != INTEGER_CST && TREE_CODE (elt) != RAW_DATA_CST)
> + if (!tree_fits_shwi_p (elt) && TREE_CODE (elt) != RAW_DATA_CST)
> return false;
>
> unsigned HOST_WIDE_INT index = tree_to_shwi (idx);
>
> Jakub
>
