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Re: patch to fix constant math - second small patch -patch ping for next stage 1


Here is the second of my wide int patches with the patch rot removed.

I would like to get these pre approved for the next stage 1.
On 10/05/2012 06:48 PM, Kenneth Zadeck 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.

Attachment: p2-3.clog
Description: Text document

diff --git a/gcc/doc/rtl.texi b/gcc/doc/rtl.texi
index b0b0723..095a642 100644
--- a/gcc/doc/rtl.texi
+++ b/gcc/doc/rtl.texi
@@ -1456,6 +1456,28 @@ 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 9907d69..f822dcd 100644
--- a/gcc/genmodes.c
+++ b/gcc/genmodes.c
@@ -848,6 +848,38 @@ 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)
 {
@@ -912,6 +944,7 @@ 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 4b58150..1062f18 100644
--- a/gcc/machmode.def
+++ b/gcc/machmode.def
@@ -179,8 +179,11 @@ 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);

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