re PR middle-end/19551 (pure (complex types) function call removed as dead (LAPACK routine claic1.f bug))

	* flow.c (propagate_one_insn): Formatting.

	PR middle-end/19551
	* flow.c (libcall_dead_p): Be more conservative if unsure.
	If there are any instructions between insn and call, see if they are
	all dead before saying the libcall is dead.

	* gcc.c-torture/execute/20050121-1.c: New test.
	* gcc.dg/20050121-2.c: New test.

From-SVN: r94145

1 files changed, 14 insertions, 4 deletions

diff --git a/gcc/flow.c b/gcc/flow.c
index 36232e9..0aa23c0 100644
--- a/gcc/flow.c
+++ b/gcc/flow.c
@@ -1581,7 +1581,7 @@ propagate_one_insn (struct propagate_block_info *pbi, rtx insn)
       pbi->cc0_live = 0;
 
       if (libcall_is_dead)
-	prev = propagate_block_delete_libcall ( insn, note);
+	prev = propagate_block_delete_libcall (insn, note);
       else
 	{
 
@@ -2284,7 +2284,7 @@ libcall_dead_p (struct propagate_block_info *pbi, rtx note, rtx insn)
     {
       rtx r = SET_SRC (x);
 
-      if (REG_P (r))
+      if (REG_P (r) || GET_CODE (r) == SUBREG)
 	{
 	  rtx call = XEXP (note, 0);
 	  rtx call_pat;
@@ -2318,10 +2318,20 @@ libcall_dead_p (struct propagate_block_info *pbi, rtx note, rtx insn)
 	      call_pat = XVECEXP (call_pat, 0, i);
 	    }
 
-	  return insn_dead_p (pbi, call_pat, 1, REG_NOTES (call));
+	  if (! insn_dead_p (pbi, call_pat, 1, REG_NOTES (call)))
+	    return 0;
+
+	  while ((insn = PREV_INSN (insn)) != call)
+	    {
+	      if (! INSN_P (insn))
+		continue;
+	      if (! insn_dead_p (pbi, PATTERN (insn), 0, REG_NOTES (insn)))
+		return 0;
+	    }
+	  return 1;
 	}
     }
-  return 1;
+  return 0;
 }
 
 /* 1 if register REGNO was alive at a place where `setjmp' was called