2006-12-12 Andrew Macleod <amacleod@redhat.com>

[pf3gnuchains/gcc-fork.git] / gcc / cselib.c

diff --git a/gcc/cselib.c b/gcc/cselib.c
index edfc328..4605388 100644 (file)
--- a/gcc/cselib.c
+++ b/gcc/cselib.c
@@ -630,14 +630,28 @@ cselib_hash_rtx (rtx x, int create)
 
       /* Assume there is only one rtx object for any given label.  */
     case LABEL_REF:
-      hash
-       += ((unsigned) LABEL_REF << 7) + (unsigned long) XEXP (x, 0);
+      /* We don't hash on the address of the CODE_LABEL to avoid bootstrap
+        differences and differences between each stage's debugging dumps.  */
+      hash += (((unsigned int) LABEL_REF << 7)
+              + CODE_LABEL_NUMBER (XEXP (x, 0)));
       return hash ? hash : (unsigned int) LABEL_REF;
 
     case SYMBOL_REF:
-      hash
-       += ((unsigned) SYMBOL_REF << 7) + (unsigned long) XSTR (x, 0);
-      return hash ? hash : (unsigned int) SYMBOL_REF;
+      {
+       /* Don't hash on the symbol's address to avoid bootstrap differences.
+          Different hash values may cause expressions to be recorded in
+          different orders and thus different registers to be used in the
+          final assembler.  This also avoids differences in the dump files
+          between various stages.  */
+       unsigned int h = 0;
+       const unsigned char *p = (const unsigned char *) XSTR (x, 0);
+
+       while (*p)
+         h += (h << 7) + *p++; /* ??? revisit */
+
+       hash += ((unsigned int) SYMBOL_REF << 7) + h;
+       return hash ? hash : (unsigned int) SYMBOL_REF;
+      }
 
     case PRE_DEC:
     case PRE_INC:
@@ -1459,9 +1473,11 @@ cselib_init (bool record_memory)
                                       sizeof (cselib_val), 10);
   value_pool = create_alloc_pool ("value", RTX_CODE_SIZE (VALUE), 100);
   cselib_record_memory = record_memory;
-  /* This is only created once.  */
+
+  /* (mem:BLK (scratch)) is a special mechanism to conflict with everything,
+     see canon_true_dependence.  This is only created once.  */
   if (! callmem)
-    callmem = gen_rtx_MEM (BLKmode, const0_rtx);
+    callmem = gen_rtx_MEM (BLKmode, gen_rtx_SCRATCH (VOIDmode));
 
   cselib_nregs = max_reg_num ();