(print_multi_reg): Do not generate a type 2 LDM instructions with writeback

enabled.
(output_return_instruction): Likewise.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@64306 138bc75d-0d04-0410-961f-82ee72b054a4

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 2326871..eadd1e8 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,5 +1,9 @@
 2003-03-13  Nick Clifton  <nickc@redhat.com>
 
+       * config/arm/arm.c (print_multi_reg): Do not generate a type 2
+        LDM instructions with writeback enabled.
+        (output_return_instruction): Likewise.
+
        * config/arm/pe.h (FIXED_REGISTERS): Remove definition.
        (CALL_USED_REGISTERS): Remove definition.
        (SUBTARGET_CONDITIONAL_REGISTER_USAGE): Define.

diff --git a/gcc/config/arm/arm.c b/gcc/config/arm/arm.c
index 808fb8c..b7c8591 100644 (file)
--- a/gcc/config/arm/arm.c
+++ b/gcc/config/arm/arm.c
@@ -7204,7 +7204,17 @@ print_multi_reg (stream, instr, reg, mask)
        not_first = TRUE;
       }
 
-  fprintf (stream, "}%s\n", TARGET_APCS_32 ? "" : "^");
+  fprintf (stream, "}");
+
+  /* Add a ^ character for the 26-bit ABI, but only if we were loading
+     the PC or not updating the stack pointer.  Otherwise we generate
+     an UNPREDICTABLE instruction.  */
+  if (! TARGET_APCS_32
+      && (((mask & (1 << PC_REGNUM)) != 0)
+         || strchr (instr, '!') == NULL))
+    fprintf (stream, "^");
+  
+  fprintf (stream, "\n");
 }
 
 /* Output a 'call' insn.  */
@@ -8210,20 +8220,26 @@ output_return_instruction (operand, really_return, reverse)
          
          if (live_regs_mask & (1 << LR_REGNUM))
            {
-             int l = strlen (return_reg);
-
-             if (! first)
-               {
-                 memcpy (p, ", ", 2);
-                 p += 2;
-               }
-
-             memcpy (p, "%|", 2);
-             memcpy (p + 2, return_reg, l);
-             strcpy (p + 2 + l, ((TARGET_APCS_32 
-                                  && !IS_INTERRUPT (func_type)) 
-                                 || !really_return) 
-                     ? "}" : "}^");
+             sprintf (p, "%s%%|%s}", first ? "" : ", ", return_reg);
+             /* Decide if we need to add the ^ symbol to the end of the
+                register list.  This causes the saved condition codes
+                register to be copied into the current condition codes
+                register.  We do the copy if we are conforming to the 32-bit
+                ABI and this is an interrupt function, or if we are
+                conforming to the 26-bit ABI.  There is a special case for
+                the 26-bit ABI however, which is if we are writing back the
+                stack pointer but not loading the PC.  In this case adding
+                the ^ symbol would create a type 2 LDM instruction, where
+                writeback is UNPREDICTABLE.  We are safe in leaving the ^
+                character off in this case however, since the actual return
+                instruction will be a MOVS which will restore the CPSR.  */
+             if ((TARGET_APCS_32 && IS_INTERRUPT (func_type))
+                 || (really_return
+                     && ! frame_pointer_needed
+                     && ((live_regs_mask & (1 << SP_REGNUM)) == 0)
+                     && ((live_regs_mask & (1 << PC_REGNUM)) == 0))
+                 )
+               strcat (p, "^");
            }
          else
            strcpy (p, "}");