reload1.c (reload): Make all entries in reg_equiv_memory_loc unshared.

	* reload1.c (reload): Make all entries in reg_equiv_memory_loc
	unshared.
	* reload.c (make_memloc): Copy result if it is still
	reg_equiv_memory_loc[regno] on return.
	(subst_reloads) [ENABLE_CHECKING]: Check that none of
	reg_equiv_constant, reg_equiv_memory_loc, reg_equiv_address and
	reg_equiv_mem are modified by the substitutions.

From-SVN: r45177

3 files changed, 47 insertions, 7 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 4b32717..f85e3d2 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,13 @@
+2001-08-25  Hans-Peter Nilsson  <hp@bitrange.com>
+
+	* reload1.c (reload): Make all entries in reg_equiv_memory_loc
+	unshared.
+	* reload.c (make_memloc): Copy result if it is still
+	reg_equiv_memory_loc[regno] on return.
+	(subst_reloads) [ENABLE_CHECKING]: Check that none of
+	reg_equiv_constant, reg_equiv_memory_loc, reg_equiv_address and
+	reg_equiv_mem are modified by the substitutions.
+
 Sat Aug 25 23:07:35 CEST 2001  Jan Hubicka  <jh@suse.cz>
 
 	* predict.c (expensive_function_p): New.
diff --git a/gcc/reload.c b/gcc/reload.c
index 73f8b21..0cf5a0e 100644
--- a/gcc/reload.c
+++ b/gcc/reload.c
@@ -4486,7 +4486,13 @@ make_memloc (ad, regno)
     tem = copy_rtx (tem);
 
   tem = replace_equiv_address_nv (reg_equiv_memory_loc[regno], tem);
-  return adjust_address_nv (tem, GET_MODE (ad), 0);
+  tem = adjust_address_nv (tem, GET_MODE (ad), 0);
+
+  /* Copy the result if it's still the same as the equivalence, to avoid
+     modifying it when we do the substitution for the reload.  */
+  if (tem == reg_equiv_memory_loc[regno])
+    tem = copy_rtx (tem);
+  return tem;
 }
 
 /* Record all reloads needed for handling memory address AD
@@ -5769,6 +5775,32 @@ subst_reloads (insn)
       register rtx reloadreg = rld[r->what].reg_rtx;
       if (reloadreg)
 	{
+#ifdef ENABLE_CHECKING
+	  /* Internal consistency test.  Check that we don't modify
+	     anything in the equivalence arrays.  Whenever something from
+	     those arrays needs to be reloaded, it must be unshared before
+	     being substituted into; the equivalence must not be modified.
+	     Otherwise, if the equivalence is used after that, it will
+	     have been modified, and the thing substituted (probably a
+	     register) is likely overwritten and not a usable equivalence.  */
+	  int check_regno;
+
+	  for (check_regno = 0; check_regno < max_regno; check_regno++)
+	    {
+#define CHECK_MODF(ARRAY)						\
+	      if (ARRAY[check_regno]					\
+		  && loc_mentioned_in_p (r->where,			\
+					 ARRAY[check_regno]))		\
+		abort ()
+
+	      CHECK_MODF (reg_equiv_constant);
+	      CHECK_MODF (reg_equiv_memory_loc);
+	      CHECK_MODF (reg_equiv_address);
+	      CHECK_MODF (reg_equiv_mem);
+#undef CHECK_MODF
+	    }
+#endif /* ENABLE_CHECKING */
+
 	  /* If we're replacing a LABEL_REF with a register, add a
 	     REG_LABEL note to indicate to flow which label this
 	     register refers to.  */
diff --git a/gcc/reload1.c b/gcc/reload1.c
index 51a2ba9..8370840 100644
--- a/gcc/reload1.c
+++ b/gcc/reload1.c
@@ -782,12 +782,10 @@ reload (first, global)
 		{
 		  if (GET_CODE (x) == MEM)
 		    {
-		      /* If the operand is a PLUS, the MEM may be shared,
-			 so make sure we have an unshared copy here.  */
-		      if (GET_CODE (XEXP (x, 0)) == PLUS)
-			x = copy_rtx (x);
-
-		      reg_equiv_memory_loc[i] = x;
+		      /* Always unshare the equivalence, so we can
+			 substitute into this insn without touching the
+			 equivalence. */
+		      reg_equiv_memory_loc[i] = copy_rtx (x);
 		    }
 		  else if (function_invariant_p (x))
 		    {