Quoting Zdenek Dvorak <rakd...@iuuk.mff.cuni.cz>:
no -- you should also test that latch contains no active insns.
I.e., factorize
out whatever forwarder_block_p does except for the test
"(dest->loop_father->header == dest)" test,
Like this?
* basic-block.h (forwarder_block_p_1): Declare.
* cfgrtl.c (orwarder_block_p_1): New function, factored out of ...
(orwarder_block_p): ... here.
--- cfgrtl.c-old 2012-10-16 15:21:06.025532573 +0100
+++ cfgrtl.c 2012-10-16 15:23:23.135529867 +0100
@@ -541,10 +541,9 @@ flow_active_insn_p (const_rtx insn)
/* Return true if the block has no effect and only forwards control flow to
its single destination. */
-/* FIXME: Make this a cfg hook. */
bool
-forwarder_block_p (const_basic_block bb)
+forwarder_block_p_1 (const_basic_block bb)
{
rtx insn;
@@ -552,6 +551,24 @@ forwarder_block_p (const_basic_block bb)
|| !single_succ_p (bb))
return false;
+ for (insn = BB_HEAD (bb); insn != BB_END (bb); insn = NEXT_INSN (insn))
+ if (INSN_P (insn) && flow_active_insn_p (insn))
+ return false;
+
+ return (!INSN_P (insn)
+ || (JUMP_P (insn) && simplejump_p (insn))
+ || !flow_active_insn_p (insn));
+}
+
+/* Likewise, but protect loop latches, headers and preheaders. */
+/* FIXME: Make this a cfg hook. */
+
+bool
+forwarder_block_p (const_basic_block bb)
+{
+ if (!forwarder_block_p_1 (bb))
+ return false;
+
/* Protect loop latches, headers and preheaders. */
if (current_loops)
{
@@ -563,13 +580,7 @@ forwarder_block_p (const_basic_block bb)
return false;
}
- for (insn = BB_HEAD (bb); insn != BB_END (bb); insn = NEXT_INSN (insn))
- if (INSN_P (insn) && flow_active_insn_p (insn))
- return false;
-
- return (!INSN_P (insn)
- || (JUMP_P (insn) && simplejump_p (insn))
- || !flow_active_insn_p (insn));
+ return true;
}
/* Return nonzero if we can reach target from src by falling through. */
