re PR rtl-optimization/50833 (ICE: in maybe_record_trace_start, at…

re PR rtl-optimization/50833 (ICE: in maybe_record_trace_start, at dwarf2cfi.c:2243 with -fshrink-wrap)

	PR rtl-optimization/50833
	* function.c (thread_prologue_and_epilogue_insns): Expect the
	return insn optimization only if optimize.

From-SVN: r180377

gcc/ChangeLog

@@ -3,6 +3,10 @@
 	PR bootstrap/50836
 	* rtlanal.c: Swap includes of "hard-reg-set.h" and "rtl.h".
 
+	PR rtl-optimization/50833
+	* function.c (thread_prologue_and_epilogue_insns): Expect the
+	return insn optimization only if optimize.
+
 2011-10-24  Georg-Johann Lay  <avr@gjlay.de>
 
 	* config/avr/avr.c: Break long lines.

gcc/function.c

@@ -5791,7 +5791,7 @@ thread_prologue_and_epilogue_insns (void)
 	 to convert jumps to it to (potentially conditional) return
 	 insns later.  This means we don't necessarily need a prologue
 	 for paths reaching it.  */
-      if (last_bb)
+      if (last_bb && optimize)
 	{
 	  if (!last_bb_active)
 	    bitmap_clear_bit (&bb_flags, last_bb->index);