I have added the proper doc. OK to commit?
Kenny
On 10/08/2012 05:06 AM, Richard Guenther wrote:
On Sat, Oct 6, 2012 at 12:48 AM, Kenneth Zadeck
<zad...@naturalbridge.com> wrote:
This patch adds machinery to genmodes.c so that largest possible sizes of
various data structures can be determined at gcc build time. These
functions create 3 symbols that are available in insn-modes.h:
MAX_BITSIZE_MODE_INT - the bitsize of the largest int.
MAX_BITSIZE_MODE_PARTIAL_INT - the bitsize of the largest partial int.
MAX_BITSIZE_MODE_ANY_INT - the largest bitsize of any kind of int.
Ok. Please document these macros in rtl.texi.
Richard.
2012-11-8 Kenneth Zadeck <zad...@naturalbridge.com>
* genmodes.c (emit_max_int): New function.
(emit_insn_modes_h): Added call to emit_max_function.
* doc/rtl.texi (MAX_BITSIZE_MODE_INT, MAX_BITSIZE_MODE_PARTIAL_INT,
MAX_BITSIZE_MODE_ANY_INT, MAX_BITSIZE_MODE_ANY_MODE): Added doc.
diff --git a/gcc/doc/rtl.texi b/gcc/doc/rtl.texi
index 07c480d..6842cb8 100644
--- a/gcc/doc/rtl.texi
+++ b/gcc/doc/rtl.texi
@@ -1458,6 +1458,28 @@ Returns the number of units contained in a mode, i.e.,
Returns the narrowest mode in mode class @var{c}.
@end table
+The following 4 variables are defined on every target. They can be
+used to allocate buffers that are guaranteed to be large enough to
+hold any value that can be represented on the target.
+
+@table @code
+@findex MAX_BITSIZE_MODE_INT
+@item MAX_BITSIZE_MODE_INT
+The bitsize of the largest integer mode defined on the target.
+
+@findex MAX_BITSIZE_MODE_PARTIAL_INT
+@item MAX_BITSIZE_MODE_PARTIAL_INT
+The bitsize of the largest partial integer mode defined on the target.
+
+@findex MAX_BITSIZE_MODE_ANY_INT
+@item MAX_BITSIZE_MODE_ANY_INT
+The maximum of MAX_BITSIZE_MODE_INT and MAX_BITSIZE_MODE_PARTIAL_INT.
+
+@findex MAX_BITSIZE_MODE_ANY_MODE
+@item MAX_BITSIZE_MODE_ANY_MODE
+The bitsize of the largest mode on the target.
+@end table
+
@findex byte_mode
@findex word_mode
The global variables @code{byte_mode} and @code{word_mode} contain modes
diff --git a/gcc/genmodes.c b/gcc/genmodes.c
index d0095c3..3e63cc7 100644
--- a/gcc/genmodes.c
+++ b/gcc/genmodes.c
@@ -849,6 +849,38 @@ calc_wider_mode (void)
#define print_closer() puts ("};")
+/* Compute the max bitsize of some of the classes of integers. It may
+ be that there are needs for the other integer classes, and this
+ code is easy to extend. */
+static void
+emit_max_int (void)
+{
+ unsigned int max, mmax;
+ struct mode_data *i;
+ int j;
+
+ puts ("");
+ for (max = 1, i = modes[MODE_INT]; i; i = i->next)
+ if (max < i->bytesize)
+ max = i->bytesize;
+ printf ("#define MAX_BITSIZE_MODE_INT %d*BITS_PER_UNIT\n", max);
+ mmax = max;
+ for (max = 1, i = modes[MODE_PARTIAL_INT]; i; i = i->next)
+ if (max < i->bytesize)
+ max = i->bytesize;
+ printf ("#define MAX_BITSIZE_MODE_PARTIAL_INT %d*BITS_PER_UNIT\n", max);
+ if (max > mmax)
+ mmax = max;
+ printf ("#define MAX_BITSIZE_MODE_ANY_INT %d*BITS_PER_UNIT\n", mmax);
+
+ mmax = 0;
+ for (j = 0; j < MAX_MODE_CLASS; j++)
+ for (i = modes[j]; i; i = i->next)
+ if (mmax < i->bytesize)
+ mmax = i->bytesize;
+ printf ("#define MAX_BITSIZE_MODE_ANY_MODE %d*BITS_PER_UNIT\n", mmax);
+}
+
static void
emit_insn_modes_h (void)
{
@@ -913,6 +945,7 @@ enum machine_mode\n{");
#endif
printf ("#define CONST_MODE_IBIT%s\n", adj_ibit ? "" : " const");
printf ("#define CONST_MODE_FBIT%s\n", adj_fbit ? "" : " const");
+ emit_max_int ();
puts ("\
\n\
#endif /* insn-modes.h */");
diff --git a/gcc/machmode.def b/gcc/machmode.def
index 631015f..7186cb4 100644
--- a/gcc/machmode.def
+++ b/gcc/machmode.def
@@ -180,8 +180,11 @@ RANDOM_MODE (BLK);
FRACTIONAL_INT_MODE (BI, 1, 1);
/* Basic integer modes. We go up to TI in generic code (128 bits).
- The name OI is reserved for a 256-bit type (needed by some back ends).
- FIXME TI shouldn't be generically available either. */
+ TImode is needed here because the some front ends now genericly
+ support __int128. If the front ends decide to generically support
+ larger types, then corresponding modes must be added here. The
+ name OI is reserved for a 256-bit type (needed by some back ends).
+ */
INT_MODE (QI, 1);
INT_MODE (HI, 2);
INT_MODE (SI, 4);
