[gcc r14-4349] lowerbitint: Fix 2 bitint lowering bugs [PR111625]

[gcc r14-4349] lowerbitint: Fix 2 bitint lowering bugs [PR111625]

[Jakub Jelinek]

https://gcc.gnu.org/g:09b512466ce302833d1624045fc5fe5afe040f58

commit r14-4349-g09b512466ce302833d1624045fc5fe5afe040f58
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Sat Sep 30 11:28:44 2023 +0200

    lowerbitint: Fix 2 bitint lowering bugs [PR111625]
    
    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.

Diff:
---
 gcc/gimple-lower-bitint.cc | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/gcc/gimple-lower-bitint.cc b/gcc/gimple-lower-bitint.cc
index d1651a06b85..66558594b51 100644
--- a/gcc/gimple-lower-bitint.cc
+++ b/gcc/gimple-lower-bitint.cc
@@ -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);