diff mbox

m68k: add missing early clobber in beq0_di, bne0_di patterns

Message ID 871tvagnb9.fsf@igel.home
State New
Headers show

Commit Message

Andreas Schwab May 31, 2014, 12:11 p.m. UTC 
This is a wrong code bug that appeared in netcdf when compiling with gcc
4.8.  Due to difference in register allocation this doesn't trigger in
4.9 or trunk, but it is obvious that the bug is only dormant.  The issue
is that if the first operand matches "o" it may contain the same
register as operand 2 as part of the address.  Clearly the register
overlap checks only make sense if the first operand matches "d".  So for
an "o" operand we need to mark the scratch register as early clobber.

Bootstrapped on m68k-suse-linux and installed in trunk.

Andreas.

	* config/m68k/m68k.md (beq0_di, bne0_di): Make the "o" constraint
	a separate alternative where the scratch operand 2 is marked as
	early clobber.
---
 gcc/config/m68k/m68k.md | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)
diff mbox

Patch

diff --git a/gcc/config/m68k/m68k.md b/gcc/config/m68k/m68k.md
index c4ebb0e..9729624 100644
--- a/gcc/config/m68k/m68k.md
+++ b/gcc/config/m68k/m68k.md
@@ -5961,15 +5961,15 @@ 
 
 (define_insn "beq0_di"
   [(set (pc)
-    (if_then_else (eq (match_operand:DI 0 "general_operand" "d*ao,<>")
+    (if_then_else (eq (match_operand:DI 0 "general_operand" "d*a,o,<>")
             (const_int 0))
-        (label_ref (match_operand 1 "" ","))
+        (label_ref (match_operand 1 "" ",,"))
         (pc)))
-   (clobber (match_scratch:SI 2 "=d,d"))]
+   (clobber (match_scratch:SI 2 "=d,&d,d"))]
   ""
 {
   CC_STATUS_INIT;
-  if (which_alternative == 1)
+  if (which_alternative == 2)
     return "move%.l %0,%2\;or%.l %0,%2\;jeq %l1";
   if ((cc_prev_status.value1
       && rtx_equal_p (cc_prev_status.value1, operands[0]))
@@ -6006,11 +6006,11 @@ 
 
 (define_insn "bne0_di"
   [(set (pc)
-    (if_then_else (ne (match_operand:DI 0 "general_operand" "do,*a")
+    (if_then_else (ne (match_operand:DI 0 "general_operand" "d,o,*a")
             (const_int 0))
-        (label_ref (match_operand 1 "" ","))
+        (label_ref (match_operand 1 "" ",,"))
         (pc)))
-   (clobber (match_scratch:SI 2 "=d,X"))]
+   (clobber (match_scratch:SI 2 "=d,&d,X"))]
   ""
 {
   if ((cc_prev_status.value1