https://gcc.gnu.org/g:568e1b4823b076235497e8fc790ded7629e472a4

commit r17-510-g568e1b4823b076235497e8fc790ded7629e472a4
Author: Alex Coplan <[email protected]>
Date:   Tue May 12 10:22:09 2026 +0100

    doc: Fix description of GET_MODE_MASK
    
    This updates the description of GET_MODE_MASK in the GCC internals
    manual.  Currently it says that the macro can only be used for modes
    whose bitsize is less than or equal to HOST_BITS_PER_INT.  That may have
    once been correct, but these days it seems to work for modes up to
    HOST_BITS_PER_WIDE_INT in size.  The code in genmodes.cc:emit_mode_mask
    seems to support this.  It has:
    
      print_maybe_const_decl ("%sunsigned HOST_WIDE_INT", "mode_mask_array",
                              "NUM_MACHINE_MODES", adj_nunits);
      puts ("\
      ((m) >= HOST_BITS_PER_WIDE_INT)             \\\n\
       ? HOST_WIDE_INT_M1U                        \\\n\
       : (HOST_WIDE_INT_1U << (m)) - 1\n");
    
    gcc/ChangeLog:
    
            * doc/rtl.texi (Machine Modes): Update description of
            GET_MODE_MASK to use HOST_BITS_PER_WIDE_INT instead of
            HOST_BITS_PER_INT as the upper limit of the input mode's bitsize.

Diff:
---
 gcc/doc/rtl.texi | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/gcc/doc/rtl.texi b/gcc/doc/rtl.texi
index 4fa4d27506cf..7fd656b70dc3 100644
--- a/gcc/doc/rtl.texi
+++ b/gcc/doc/rtl.texi
@@ -1577,9 +1577,9 @@ Returns the number of fractional bits of a datum of 
fixed-point mode @var{m}.
 
 @findex GET_MODE_MASK
 @item GET_MODE_MASK (@var{m})
-Returns a bitmask containing 1 for all bits in a word that fit within
-mode @var{m}.  This macro can only be used for modes whose bitsize is
-less than or equal to @code{HOST_BITS_PER_INT}.
+Returns a bitmask containing 1 for all bits in a @code{HOST_WIDE_INT}
+that fit within mode @var{m}.  This macro can only be used for modes
+whose bitsize is less than or equal to @code{HOST_BITS_PER_WIDE_INT}.
 
 @findex GET_MODE_ALIGNMENT
 @item GET_MODE_ALIGNMENT (@var{m})

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