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lowerbitint: Fix 2 bitint lowering bugs [PR111625]

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This patch fixes 2 issues.  One is when we want to get address of
an uninitialized large/huge bitint SSA_NAME for multiplication/division/modulo
or conversion to floating point (binary or decimal), the code just creates
an uninitialized limb sized variable and passes address of that, but I forgot
to initialize *prec in that case, so it invoked UB at compile time rather
than at runtime.  As it is UB, we could use anything valid as precision there,
say 2 bits for signed, 1 bit for unsigned as smallest possible set of values,
or full bitint precision as full random value.  Though, because we only pass
address to a single limb, I think it is best to pass the bitsize of the limb.

And the other issue is that when ranger in range_to_prec finds some range
is undefined_p (), it will assert {lower,upper}_bound () method isn't called
on it, but we were.  So, the patch adjusts range_to_proc to treat it like
the !optimized case, full bitint precision.

2023-09-30  Jakub Jelinek  <jakub@redhat.com>

	PR middle-end/111625
	PR middle-end/111637
	* gimple-lower-bitint.cc (range_to_prec): Use prec or -prec if
	r.undefined_p ().
	(bitint_large_huge::handle_operand_addr): For uninitialized operands
	use limb_prec or -limb_prec precision.
This commit is contained in:
Jakub Jelinek 2023-09-30 11:28:44 +02:00
parent 9d249b7e31
commit 09b512466c
1 changed files with 5 additions and 1 deletions
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6
gcc/gimple-lower-bitint.cc
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@ -1932,7 +1932,8 @@ range_to_prec (tree op, gimple *stmt)
unsigned int prec = TYPE_PRECISION (type);
if (!optimize
|| !get_range_query (cfun)->range_of_expr (r, op, stmt))
|| !get_range_query (cfun)->range_of_expr (r, op, stmt)
|| r.undefined_p ())
{
if (TYPE_UNSIGNED (type))
return prec;
@ -2066,6 +2067,9 @@ bitint_large_huge::handle_operand_addr (tree op, gimple *stmt,
}
else if (gimple_code (g) == GIMPLE_NOP)
{
*prec = TYPE_UNSIGNED (TREE_TYPE (op)) ? limb_prec : -limb_prec;
if (prec_stored)
*prec_stored = *prec;
tree var = create_tmp_var (m_limb_type);
TREE_ADDRESSABLE (var) = 1;
ret = build_fold_addr_expr (var);