[gcc r17-3558] forwprop: Update comment about the shift

https://gcc.gnu.org/g:e191d71a0627e0ba87c4b002a5fb826f181602ef

commit r17-3558-ge191d71a0627e0ba87c4b002a5fb826f181602ef
Author: Andrea Pinski <[email protected]>
Date:   Sat Aug 22 18:58:11 2026 -0700

    forwprop: Update comment about the shift
    
    This updates about the comment on why tree_to_uhwi
    is safe. To say it is always less than TYPE_PRECISION.
    
    Pushed as obvious.
    
    gcc/ChangeLog:
    
            * tree-ssa-forwprop.cc (long_mul_set_summand): Update
            comment on the shift.
    
    Signed-off-by: Andrea Pinski <[email protected]>

Diff:
---
 gcc/tree-ssa-forwprop.cc | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/gcc/tree-ssa-forwprop.cc b/gcc/tree-ssa-forwprop.cc
index 3433e3d02b9e..c31dd1c94ec0 100644
--- a/gcc/tree-ssa-forwprop.cc
+++ b/gcc/tree-ssa-forwprop.cc
@@ -3891,8 +3891,7 @@ long_mul_set_summand (long_mul_summand *info, long_mul_kind kind,
     info->hilo[i] = res_ops[n_ops + i];
   if (shift_idx >= 0)
     /* The carry atoms (mul_carry_cross_sum, mul_carry_low_sum) capture the
-       shift as an INTEGER_CST already checked with tree_fits_uhwi_p, so this
-       cannot overflow.  */
+       shift since it is always less than TYPE_PRECISION, using tree_to_uhwi is safe.  */
     info->shift = tree_to_uhwi (res_ops[shift_idx]);
 }