Makefile.in (emit-rtl.o): Depend on HASHTAB_H.

	* Makefile.in (emit-rtl.o): Depend on HASHTAB_H.
	* alias.c (reg_known_value): Add comments.
	(init_alias_analysis): Likewise.
	* cse.c (exp_equiv_p): CONST_INTs are equal iff they have the same
	address.
	(cse_basic_block): Fix typo in comment.
	* emit-rtl.c: Include hashtab.h.
	(const_int_htab): New variable.
	(const_int_htab_hash): New function.
	(const_int_htab_eq): Likewise.
	(rtx_htab_mark_1): Likewise.
	(rtx_htab_mark): Likewise.
	(gen_rtx_CONST_INT): Cache all CONST_INTs.
	(unshare_all_rtx): Fix formatting.
	(init_emit_once): Initialize const_int_htab.
	* rtl.c (rtx_equal_p): CONST_INTs are equal iff they have the same
	address.
	* rtl.texi: Document the fact that all CONST_INTs with the same
	value are shared.

From-SVN: r32844

7 files changed, 137 insertions, 32 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 57d2bed..0088fd1 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,25 @@
+2000-03-30  Mark Mitchell  <mark@codesourcery.com>
+
+	* Makefile.in (emit-rtl.o): Depend on HASHTAB_H.
+	* alias.c (reg_known_value): Add comments.
+	(init_alias_analysis): Likewise.
+	* cse.c (exp_equiv_p): CONST_INTs are equal iff they have the same
+	address.
+	(cse_basic_block): Fix typo in comment.
+	* emit-rtl.c: Include hashtab.h.
+	(const_int_htab): New variable.
+	(const_int_htab_hash): New function.
+	(const_int_htab_eq): Likewise.
+	(rtx_htab_mark_1): Likewise.
+	(rtx_htab_mark): Likewise.
+	(gen_rtx_CONST_INT): Cache all CONST_INTs.
+	(unshare_all_rtx): Fix formatting.
+	(init_emit_once): Initialize const_int_htab.
+	* rtl.c (rtx_equal_p): CONST_INTs are equal iff they have the same
+	address.
+	* rtl.texi: Document the fact that all CONST_INTs with the same
+	value are shared.
+
 2000-03-30  Richard Henderson  <rth@cygnus.com>
 
 	* alpha.h (FUNCTION_BOUNDARY): Reduce to 128 bits.
diff --git a/gcc/Makefile.in b/gcc/Makefile.in
index 2c0096a..ee53e28 100644
--- a/gcc/Makefile.in
+++ b/gcc/Makefile.in
@@ -1546,7 +1546,8 @@ xcoffout.o : xcoffout.c $(CONFIG_H) system.h $(TREE_H) $(RTL_H) xcoffout.h \
    flags.h toplev.h output.h dbxout.h ggc.h
 emit-rtl.o : emit-rtl.c $(CONFIG_H) system.h $(RTL_H) $(TREE_H) flags.h \
    function.h $(REGS_H) insn-config.h $(RECOG_H) real.h ggc.h \
-   $(EXPR_H) $(srcdir)/../include/obstack.h hard-reg-set.h bitmap.h toplev.h
+   $(EXPR_H) $(srcdir)/../include/obstack.h hard-reg-set.h bitmap.h toplev.h \
+   $(HASHTAB_H)
 real.o : real.c $(CONFIG_H) system.h $(TREE_H) toplev.h
 integrate.o : integrate.c $(CONFIG_H) system.h $(RTL_H) $(TREE_H) flags.h \
    $(INTEGRATE_H) insn-flags.h insn-config.h $(EXPR_H) real.h $(REGS_H) \
diff --git a/gcc/alias.c b/gcc/alias.c
index 8d16330..d413ec2 100644
--- a/gcc/alias.c
+++ b/gcc/alias.c
@@ -153,8 +153,10 @@ static unsigned int reg_base_value_size; /* size of reg_base_value array */
    after reload.  */
 static rtx *alias_invariant;
 
-/* Vector indexed by N giving the initial (unchanging) value known
-   for pseudo-register N.  */
+/* Vector indexed by N giving the initial (unchanging) value known for
+   pseudo-register N.  This array is initialized in
+   init_alias_analysis, and does not change until end_alias_analysis
+   is called.  */
 rtx *reg_known_value;
 
 /* Indicates number of valid entries in reg_known_value.  */
@@ -1570,6 +1572,9 @@ init_alias_once ()
   alias_sets = splay_tree_new (splay_tree_compare_ints, 0, 0);
 }
 
+/* Initialize the aliasing machinery.  Initialize the REG_KNOWN_VALUE
+   array.  */
+
 void
 init_alias_analysis ()
 {
diff --git a/gcc/cse.c b/gcc/cse.c
index 03772b0..c936a15 100644
--- a/gcc/cse.c
+++ b/gcc/cse.c
@@ -2367,10 +2367,8 @@ exp_equiv_p (x, y, validate, equal_values)
     {
     case PC:
     case CC0:
-      return x == y;
-
     case CONST_INT:
-      return INTVAL (x) == INTVAL (y);
+      return x == y;
 
     case LABEL_REF:
       return XEXP (x, 0) == XEXP (y, 0);
@@ -6898,7 +6896,7 @@ cse_basic_block (from, to, next_branch, around_loop)
 
       /* If we have processed 1,000 insns, flush the hash table to
 	 avoid extreme quadratic behavior.  We must not include NOTEs
-	 in the count since there may be more or them when generating
+	 in the count since there may be more of them when generating
 	 debugging information.  If we clear the table at different
 	 times, code generated with -g -O might be different than code
 	 generated with -O but not -g.
diff --git a/gcc/emit-rtl.c b/gcc/emit-rtl.c
index cf8f523..246805c 100644
--- a/gcc/emit-rtl.c
+++ b/gcc/emit-rtl.c
@@ -46,6 +46,7 @@ Boston, MA 02111-1307, USA.  */
 #include "expr.h"
 #include "regs.h"
 #include "hard-reg-set.h"
+#include "hashtab.h"
 #include "insn-config.h"
 #include "recog.h"
 #include "real.h"
@@ -137,6 +138,11 @@ rtx return_address_pointer_rtx;	/* (REG:Pmode RETURN_ADDRESS_POINTER_REGNUM) */
 
 rtx const_int_rtx[MAX_SAVED_CONST_INT * 2 + 1];
 
+/* A hash table storing CONST_INTs whose absolute value is greater
+   than MAX_SAVED_CONST_INT.  */
+
+static htab_t const_int_htab;
+
 /* start_sequence and gen_sequence can make a lot of rtx expressions which are
    shortly thrown away.  We use two mechanisms to prevent this waste:
 
@@ -172,16 +178,67 @@ static rtx make_call_insn_raw		PARAMS ((rtx));
 static rtx find_line_note		PARAMS ((rtx));
 static void mark_sequence_stack         PARAMS ((struct sequence_stack *));
 static void unshare_all_rtl_1		PARAMS ((rtx));
+static hashval_t const_int_htab_hash    PARAMS ((const void *));
+static int const_int_htab_eq            PARAMS ((const void *,
+						 const void *));
+static int rtx_htab_mark_1              PARAMS ((void **, void *));
+static void rtx_htab_mark               PARAMS ((void *));
+
 
+/* Returns a hash code for X (which is a really a CONST_INT).  */
+
+static hashval_t
+const_int_htab_hash (x)
+     const void *x;
+{
+  return (hashval_t) INTVAL ((rtx) x);
+}
+
+/* Returns non-zero if the value represented by X (which is really a
+   CONST_INT) is the same as that given by Y (which is really a
+   HOST_WIDE_INT *).  */
+
+static int
+const_int_htab_eq (x, y)
+     const void *x;
+     const void *y;
+{
+  return (INTVAL ((rtx) x) == *((HOST_WIDE_INT *) y));
+}
+
+/* Mark the hash-table element X (which is really a pointer to an
+   rtx).  */
+
+static int
+rtx_htab_mark_1 (x, data)
+     void **x;
+     void *data ATTRIBUTE_UNUSED;
+{
+  ggc_mark_rtx (*x);
+  return 1;
+}
+
+/* Mark all the elements of HTAB (which is really an htab_t full of
+   rtxs).  */
+
+static void
+rtx_htab_mark (htab)
+     void *htab;
+{
+  htab_traverse (*((htab_t *) htab), rtx_htab_mark_1, NULL);
+}
+
 /* There are some RTL codes that require special attention; the generation
    functions do the raw handling.  If you add to this list, modify
    special_rtx in gengenrtl.c as well.  */
 
 rtx
 gen_rtx_CONST_INT (mode, arg)
-     enum machine_mode mode;
+     enum machine_mode mode ATTRIBUTE_UNUSED;
      HOST_WIDE_INT arg;
 {
+  void **slot;
+
   if (arg >= - MAX_SAVED_CONST_INT && arg <= MAX_SAVED_CONST_INT)
     return const_int_rtx[arg + MAX_SAVED_CONST_INT];
 
@@ -190,7 +247,15 @@ gen_rtx_CONST_INT (mode, arg)
     return const_true_rtx;
 #endif
 
-  return gen_rtx_raw_CONST_INT (mode, arg);
+  /* Look up the CONST_INT in the hash table.  */
+  slot = htab_find_slot_with_hash (const_int_htab, 
+				   &arg,
+				   (hashval_t) arg,
+				   /*insert=*/1);
+  if (!*slot)
+    *slot = gen_rtx_raw_CONST_INT (VOIDmode, arg);
+
+  return (rtx) *slot;
 }
 
 /* CONST_DOUBLEs needs special handling because its length is known
@@ -1627,9 +1692,7 @@ unshare_all_rtl (fndecl, insn)
 
   /* Make sure that virtual parameters are not shared.  */
   for (decl = DECL_ARGUMENTS (fndecl); decl; decl = TREE_CHAIN (decl))
-    {
-      copy_rtx_if_shared (DECL_RTL (decl));
-    }
+    copy_rtx_if_shared (DECL_RTL (decl));
 
   /* Unshare just about everything else.  */
   unshare_all_rtl_1 (insn);
@@ -4083,6 +4146,14 @@ init_emit_once (line_numbers)
   ggc_add_rtx_root (&static_chain_rtx, 1);
   ggc_add_rtx_root (&static_chain_incoming_rtx, 1);
   ggc_add_rtx_root (&return_address_pointer_rtx, 1);
+
+  /* Initialize the CONST_INT hash table.  */
+  const_int_htab = htab_create (37, 
+				const_int_htab_hash, 
+				const_int_htab_eq, 
+				NULL);
+  ggc_add_root (&const_int_htab, 1, sizeof (const_int_htab), 
+		rtx_htab_mark);
 }
 
 /* Query and clear/ restore no_line_numbers.  This is used by the
diff --git a/gcc/rtl.c b/gcc/rtl.c
index 5f0073d..bfe3806 100644
--- a/gcc/rtl.c
+++ b/gcc/rtl.c
@@ -613,22 +613,32 @@ rtx_equal_p (x, y)
   if (GET_MODE (x) != GET_MODE (y))
     return 0;
 
-  /* REG, LABEL_REF, and SYMBOL_REF can be compared nonrecursively.  */
-
-  if (code == REG)
-    /* Until rtl generation is complete, don't consider a reference to the
-       return register of the current function the same as the return from a
-       called function.  This eases the job of function integration.  Once the
-       distinction is no longer needed, they can be considered equivalent.  */
-    return (REGNO (x) == REGNO (y)
-	    && (! rtx_equal_function_value_matters
-		|| REG_FUNCTION_VALUE_P (x) == REG_FUNCTION_VALUE_P (y)));
-  else if (code == LABEL_REF)
-    return XEXP (x, 0) == XEXP (y, 0);
-  else if (code == SYMBOL_REF)
-    return XSTR (x, 0) == XSTR (y, 0);
-  else if (code == SCRATCH || code == CONST_DOUBLE)
-    return 0;
+  /* Some RTL can be compared nonrecursively.  */
+  switch (code)
+    {
+    case REG:
+      /* Until rtl generation is complete, don't consider a reference to the
+	 return register of the current function the same as the return from a
+	 called function.  This eases the job of function integration.  Once the
+	 distinction is no longer needed, they can be considered equivalent.  */
+      return (REGNO (x) == REGNO (y)
+	      && (! rtx_equal_function_value_matters
+		  || REG_FUNCTION_VALUE_P (x) == REG_FUNCTION_VALUE_P (y)));
+
+    case LABEL_REF:
+      return XEXP (x, 0) == XEXP (y, 0);
+
+    case SYMBOL_REF:
+      return XSTR (x, 0) == XSTR (y, 0);
+
+    case SCRATCH:
+    case CONST_DOUBLE:
+    case CONST_INT:
+      return 0;
+
+    default:
+      break;
+    }
 
   /* Compare the elements.  If any pair of corresponding elements
      fail to match, return 0 for the whole things.  */
diff --git a/gcc/rtl.texi b/gcc/rtl.texi
index 06fe383..55208ae 100644
--- a/gcc/rtl.texi
+++ b/gcc/rtl.texi
@@ -1,4 +1,4 @@
-@c Copyright (C) 1988, 89, 92, 94, 97, 1998, 1999 Free Software Foundation, Inc.
+@c Copyright (C) 1988, 89, 92, 94, 97, 1998, 1999, 2000 Free Software Foundation, Inc.
 @c This is part of the GCC manual.
 @c For copying conditions, see the file gcc.texi.
 
@@ -2917,9 +2917,7 @@ referring to it.
 
 @cindex @code{const_int}, RTL sharing
 @item
-There is only one @code{const_int} expression with value 0, only
-one with value 1, and only one with value @minus{}1.
-Some other integer values are also stored uniquely.
+All @code{const_int} expressions with equal values are shared.
 
 @cindex @code{pc}, RTL sharing
 @item