Re: delete LIBCALL note after split

[Sa Liu <SALIU at de dot ibm dot com>]

Ian Lance Taylor <iant@google.com> wrote on 30.07.2007 18:59:28:

> If the compiler splits an insn with a REG_LIBCALL note, it needs to
> remove the corresponding REG_RETVAL note, or it needs to relink the
> insns.  This looks like a compiler bug, in that try_split doesn't
> handle REG_LIBCALL notes at all.  It's quite unusual to be able to
> split a libcall insn, so it's not surprising that this has not been
> noticed previously.
> 
> Ian

Thanks for replying, Ian!

I have added a piece of code in try_split to handle the links. Not sure 
whether this is O.K. for the other platforms.

Index: gcc/emit-rtl.c
===================================================================
--- gcc.orig/emit-rtl.c
+++ gcc/emit-rtl.c
@@ -3121,7 +3121,7 @@ try_split (rtx pat, rtx trial, int last)
   rtx before = PREV_INSN (trial);
   rtx after = NEXT_INSN (trial);
   int has_barrier = 0;
-  rtx tem;
+  rtx tem, note_libcall, note_retval;
   rtx note, seq;
   int probability;
   rtx insn_last, insn;
@@ -3257,6 +3257,17 @@ try_split (rtx pat, rtx trial, int last)
          break;
 #endif
 
+       case REG_LIBCALL:
+       /* Relink the insns with REG_LIBCALL note and with REG_RETVAL note 

+          after split.  */
+           note_libcall 
+                = find_reg_note (trial, REG_LIBCALL, NULL); 
+           REG_NOTES (insn_last) = note_libcall;
+           note_retval 
+                = find_reg_note (XEXP (note_libcall, 0), REG_RETVAL, 
NULL);
+           XEXP (note_retval, 0) = insn_last;
+         break;
+
        default:
          break;
        }

Thanks,
Sa