Re: [Patch]: Fix pb in libcall_dead_p

[Stephane Carrez <Stephane dot Carrez at worldnet dot fr>]

Hi!

As requested by Richard, I've used 'single_set' to solve my libcall_dead_p()
problem.

I have two fixes to propose, a simple one that just calls single_set,
and an alternative that is the same with a cleanup: the 'x' parameter is
useless now, the second fix 'flow.c.diff-2' removes it.  You choose the fix
you prefer.

Thanks,
	Stephane


ChangeLog for flow.c.diff

2000-06-28  Stephane Carrez  <Stephane.Carrez@worldnet.fr>

	* flow.c (libcall_dead_p): Use single_set to verify the insn
	has only one set and get for analysis.



ChangeLog for flow.c.diff-2

2000-06-28  Stephane Carrez  <Stephane.Carrez@worldnet.fr>

	* flow.c (libcall_dead_p): Use single_set to verify the insn
	has only one set and get for analysis.
	(propagate_one_insn): Don't pass the PATTERN of the insn.
--- /src/gnu/cygnus/gcc/gcc/flow.c	Sun Jun 25 11:20:05 2000
+++ gcc/gcc/flow.c	Wed Jun 28 10:30:10 2000
@@ -4021,9 +4021,8 @@ libcall_dead_p (pbi, x, note, insn)
      rtx note;
      rtx insn;
 {
-  register RTX_CODE code = GET_CODE (x);
-
-  if (code == SET)
+  x = single_set (insn);
+  if (x)
     {
       register rtx r = SET_SRC (x);
       if (GET_CODE (r) == REG)
--- /src/gnu/cygnus/gcc/gcc/flow.c	Sun Jun 25 11:20:05 2000
+++ gcc/gcc/flow.c	Wed Jun 28 10:39:57 2000
@@ -354,7 +354,7 @@ static rtx propagate_block_delete_libcal
 static int insn_dead_p			PARAMS ((struct propagate_block_info *,
 						 rtx, int, rtx));
 static int libcall_dead_p		PARAMS ((struct propagate_block_info *,
-						 rtx, rtx, rtx));
+						 rtx, rtx));
 static void mark_set_regs		PARAMS ((struct propagate_block_info *,
 						 rtx, rtx));
 static void mark_set_1			PARAMS ((struct propagate_block_info *,
@@ -3417,8 +3417,7 @@ propagate_one_insn (pbi, insn)
       insn_is_dead = insn_dead_p (pbi, PATTERN (insn), 0,
 				  REG_NOTES (insn));
       libcall_is_dead = (insn_is_dead && note != 0
-			 && libcall_dead_p (pbi, PATTERN (insn),
-					    note, insn));
+			 && libcall_dead_p (pbi, note, insn));
     }
 
   /* We almost certainly don't want to delete prologue or epilogue
@@ -4000,30 +3999,30 @@ insn_dead_p (pbi, x, call_ok, notes)
   return 0;
 }
 
-/* If X is the pattern of the last insn in a libcall, and assuming X is dead,
+/* If INSN is the last insn in a libcall, and assuming INSN is dead,
    return 1 if the entire library call is dead.
-   This is true if X copies a register (hard or pseudo)
-   and if the hard return  reg of the call insn is dead.
-   (The caller should have tested the destination of X already for death.)
+   This is true if INSN copies a register (hard or pseudo)
+   and if the hard return reg of the call insn is dead.
+   (The caller should have tested the destination of the SET inside
+   INSN already for death.)
 
    If this insn doesn't just copy a register, then we don't
    have an ordinary libcall.  In that case, cse could not have
    managed to substitute the source for the dest later on,
    so we can assume the libcall is dead.
 
-   NEEDED is the bit vector of pseudoregs live before this insn.
-   NOTE is the REG_RETVAL note of the insn.  INSN is the insn itself.  */
+   PBI is the block info giving pseudoregs live before this insn.
+   NOTE is the REG_RETVAL note of the insn.  */
 
 static int
-libcall_dead_p (pbi, x, note, insn)
+libcall_dead_p (pbi, note, insn)
      struct propagate_block_info *pbi;
-     rtx x;
      rtx note;
      rtx insn;
 {
-  register RTX_CODE code = GET_CODE (x);
+  rtx x = single_set (insn);
 
-  if (code == SET)
+  if (x)
     {
       register rtx r = SET_SRC (x);
       if (GET_CODE (r) == REG)