re PR rtl-optimization/13424 (gcc.dg/20031202-1.c is miscompiled)

	PR optimization/13424
	* expr.c (store_constructor): Revert 2003-12-03 change.

	* emit-rtl.c (change_address): Check also if MEM_ATTRS is set as
	expected before returning early.  Avoid sharing RTL if they
	need to be changed.

	* config/i386/i386.c (ix86_expand_movstr): Rework rep_mov and strmov
	handling so that memory attributes are preserved.  Don't call
	ix86_set_move_mem_attrs.
	(ix86_set_move_mem_attrs_1, ix86_set_move_mem_attrs): Removed.
	(ix86_expand_clrstr): Rename src argument to
	dst.  Rework rep_stos and strset handling so that memory attributes
	are preserved.
	(ix86_expand_strlen): Pass src argument to
	ix86_expand_strlensi_unroll_1.  Rework strlenqi_1 handling so that
	memory attributes are preserved.
	(ix86_expand_strlensi_unroll_1): Add src argument.  Use
	change_address instead of gen_rtx_MEM.
	* config/i386/i386.md (strmov, strmov_singleop, rep_mov): New
	expanders.
	(strmovdi_rex64, strmovsi, strmovsi_rex64, strmovhi, strmovhi_rex64,
	strmovqi, strmovqi_rex64): Remove.
	(rep_mov*, strmov*): Prefix insn names with *.
	(strset, strset_singleop, rep_stos): New expanders.
	(strsetdi_rex64, strsetsi, strsetsi_rex64, strsethi, strsethi_rex64,
	strsetqi, strsetqi_rex64): Remove.
	(rep_stos*, strset*): Prefix insn names with *.
	(rep_stosqi_rex64): Likewise.  Fix mode of dirflag reg from DImode
	to SImode.
	(cmpstrsi): Rework cmpstrqi_1 handling so that memory attributes
	are preserved.
	(cmpstrqi_nz_1, cmpstrqi_nz_rex_1, cmpstrqi_1, cmpstrqi_rex_1):
	Prefix insn names with *.
	(cmpstrqi_nz_1, cmpstrqi_1): New expanders.
	(strlenqi_1, strlenqi_rex_1): Prefix insn names with *.
	(strlenqi_1): New expander.
	* config/i386/i386.h (ix86_set_move_mem_attrs): Remove prototype.

From-SVN: r76852

gcc/ChangeLog

+2004-01-29  Jakub Jelinek  <jakub@redhat.com>
+
+	PR optimization/13424
+	* expr.c (store_constructor): Revert 2003-12-03 change.
+
+	* emit-rtl.c (change_address): Check also if MEM_ATTRS is set as
+	expected before returning early.  Avoid sharing RTL if they
+	need to be changed.
+
+	* config/i386/i386.c (ix86_expand_movstr): Rework rep_mov and strmov
+	handling so that memory attributes are preserved.  Don't call
+	ix86_set_move_mem_attrs.
+	(ix86_set_move_mem_attrs_1, ix86_set_move_mem_attrs): Removed.
+	(ix86_expand_clrstr): Rename src argument to
+	dst.  Rework rep_stos and strset handling so that memory attributes
+	are preserved.
+	(ix86_expand_strlen): Pass src argument to
+	ix86_expand_strlensi_unroll_1.  Rework strlenqi_1 handling so that
+	memory attributes are preserved.
+	(ix86_expand_strlensi_unroll_1): Add src argument.  Use
+	change_address instead of gen_rtx_MEM.
+	* config/i386/i386.md (strmov, strmov_singleop, rep_mov): New
+	expanders.
+	(strmovdi_rex64, strmovsi, strmovsi_rex64, strmovhi, strmovhi_rex64,
+	strmovqi, strmovqi_rex64): Remove.
+	(rep_mov*, strmov*): Prefix insn names with *.
+	(strset, strset_singleop, rep_stos): New expanders.
+	(strsetdi_rex64, strsetsi, strsetsi_rex64, strsethi, strsethi_rex64,
+	strsetqi, strsetqi_rex64): Remove.
+	(rep_stos*, strset*): Prefix insn names with *.
+	(rep_stosqi_rex64): Likewise.  Fix mode of dirflag reg from DImode
+	to SImode.
+	(cmpstrsi): Rework cmpstrqi_1 handling so that memory attributes
+	are preserved.
+	(cmpstrqi_nz_1, cmpstrqi_nz_rex_1, cmpstrqi_1, cmpstrqi_rex_1):
+	Prefix insn names with *.
+	(cmpstrqi_nz_1, cmpstrqi_1): New expanders.
+	(strlenqi_1, strlenqi_rex_1): Prefix insn names with *.
+	(strlenqi_1): New expander.
+	* config/i386/i386.h (ix86_set_move_mem_attrs): Remove prototype.
+
 2004-01-29  Zdenek Dvorak  <rakdver@atrey.karlin.mff.cuni.cz>
 
 	* Makefile.in (cfghooks.o): Add TIMEVAR_H and toplev.h dependency.

gcc/config/i386/i386-protos.h

@@ -178,7 +178,6 @@ extern int ix86_secondary_memory_needed (enum reg_class, enum reg_class,
 					 enum machine_mode, int);
 extern enum reg_class ix86_preferred_reload_class (rtx, enum reg_class);
 extern int ix86_memory_move_cost (enum machine_mode, enum reg_class, int);
-extern void ix86_set_move_mem_attrs (rtx, rtx, rtx, rtx, rtx);
 extern void emit_i387_cw_initialization (rtx, rtx);
 extern bool ix86_fp_jump_nontrivial_p (enum rtx_code);
 extern void x86_order_regs_for_local_alloc (void);

gcc/emit-rtl.c

@@ -1869,19 +1869,29 @@ change_address_1 (rtx memref, enum machine_mode mode, rtx addr, int validate)
 rtx
 change_address (rtx memref, enum machine_mode mode, rtx addr)
 {
-  rtx new = change_address_1 (memref, mode, addr, 1);
+  rtx new = change_address_1 (memref, mode, addr, 1), size;
   enum machine_mode mmode = GET_MODE (new);
+  unsigned int align;
+
+  size = mmode == BLKmode ? 0 : GEN_INT (GET_MODE_SIZE (mmode));
+  align = mmode == BLKmode ? BITS_PER_UNIT : GET_MODE_ALIGNMENT (mmode);
 
   /* If there are no changes, just return the original memory reference.  */
   if (new == memref)
-    return new;
+    {
+      if (MEM_ATTRS (memref) == 0
+	  || (MEM_EXPR (memref) == NULL
+	      && MEM_OFFSET (memref) == NULL
+	      && MEM_SIZE (memref) == size
+	      && MEM_ALIGN (memref) == align))
+	return new;
+
+      new = gen_rtx_MEM (mmode, addr);
+      MEM_COPY_ATTRIBUTES (new, memref);
+    }
 
   MEM_ATTRS (new)
-    = get_mem_attrs (MEM_ALIAS_SET (memref), 0, 0,
-		     mmode == BLKmode ? 0 : GEN_INT (GET_MODE_SIZE (mmode)),
-		     (mmode == BLKmode ? BITS_PER_UNIT
-		      : GET_MODE_ALIGNMENT (mmode)),
-		     mmode);
+    = get_mem_attrs (MEM_ALIAS_SET (memref), 0, 0, size, align, mmode);
 
   return new;
 }

gcc/expr.c

@@ -4619,10 +4619,7 @@ store_constructor (tree exp, rtx target, int cleared, HOST_WIDE_INT size)
 				       highest_pow2_factor (offset));
 	    }
 
-	  /* If the constructor has been cleared, setting RTX_UNCHANGING_P
-	     on the MEM might lead to scheduling the clearing after the
-	     store.  */
-	  if (TREE_READONLY (field) && !cleared)
+	  if (TREE_READONLY (field))
 	    {
 	      if (GET_CODE (to_rtx) == MEM)
 		to_rtx = copy_rtx (to_rtx);