sparc.md (ldd peephole2s): Fix final arg to mems_ok_for_ldd_peep when the order…

sparc.md (ldd peephole2s): Fix final arg to mems_ok_for_ldd_peep when the order of the loads being...

2002-04-02  David S. Miller  <davem@redhat.com>

	* config/sparc/sparc.md (ldd peephole2s): Fix final arg to
	mems_ok_for_ldd_peep when the order of the loads being examined
	is reversed.
	* config/sparc/sparc.c (mems_ok_for_ldd_peep): Expand upon
	existing comment to increase comprehension of this situation.

From-SVN: r51796

gcc/ChangeLog

+2002-04-02  David S. Miller  <davem@redhat.com>
+
+	* config/sparc/sparc.md (ldd peephole2s): Fix final arg to
+	mems_ok_for_ldd_peep when the order of the loads being examined
+	is reversed.
+	* config/sparc/sparc.c (mems_ok_for_ldd_peep): Expand upon
+	existing comment to increase comprehension of this situation.
+
 2002-04-02  Zack Weinberg  <zack@codesourcery.com>
 
 	* config/sh/sh.md: Don't use union real_extract.

gcc/config/sparc/sparc.c

@@ -5798,6 +5798,20 @@ registers_ok_for_ldd_peep (reg1, reg2)
 	ld [%o0 + 4], %o1
    to
    	ldd [%o0], %o0
+   nor:
+	ld [%g3 + 4], %g3
+	ld [%g3], %g2
+   to
+        ldd [%g3], %g2
+
+   But, note that the transformation from:
+	ld [%g2 + 4], %g3
+        ld [%g2], %g2
+   to
+	ldd [%g2], %g2
+   is perfectly fine.  Thus, the peephole2 patterns always pass us
+   the destination register of the first load, never the second one.
+
    For stores we don't have a similar problem, so dependent_reg_rtx is
    NULL_RTX.  */
 

gcc/config/sparc/sparc.md

@@ -9062,7 +9062,7 @@
    (set (match_operand:SI 2 "register_operand" "")
         (match_operand:SI 3 "memory_operand" ""))]
   "registers_ok_for_ldd_peep (operands[2], operands[0]) 
-  && mems_ok_for_ldd_peep (operands[3], operands[1], operands[2])"
+  && mems_ok_for_ldd_peep (operands[3], operands[1], operands[0])"
   [(set (match_dup 2)
 	(match_dup 3))]
    "operands[3] = change_address (operands[3], DImode, NULL);
@@ -9087,7 +9087,7 @@
    (set (match_operand:SF 2 "register_operand" "")
         (match_operand:SF 3 "memory_operand" ""))]
   "registers_ok_for_ldd_peep (operands[2], operands[0]) 
-  && mems_ok_for_ldd_peep (operands[3], operands[1], operands[2])"
+  && mems_ok_for_ldd_peep (operands[3], operands[1], operands[0])"
   [(set (match_dup 2)
 	(match_dup 3))]
   "operands[3] = change_address (operands[3], DFmode, NULL);