re PR rtl-optimization/15068 (ICE in elim_reg_cond)

	PR rtl-optimization/15068
	* flow.c (init_propagate_block_info): Check condition is reversible.

From-SVN: r85439

gcc/ChangeLog

+2004-08-02  Paul Brook  <paul@codesourcery.com>
+
+	PR rtl-optimization/15068
+	* flow.c (init_propagate_block_info): Check condition is reversible.
+
 2004-08-02  Gabriel Dos Reis  <gdr@integrable-solutions.net>
 
 	* gengtype.h (options::info): Change type to const char *.

gcc/flow.c

@@ -1865,19 +1865,22 @@ init_propagate_block_info (basic_block bb, regset live, regset local_set,
 	  rtx set_src = SET_SRC (pc_set (BB_END (bb)));
 	  rtx cond_true = XEXP (set_src, 0);
 	  rtx reg = XEXP (cond_true, 0);
+ 	  enum rtx_code inv_cond;
 
 	  if (GET_CODE (reg) == SUBREG)
 	    reg = SUBREG_REG (reg);
 
 	  /* We can only track conditional lifetimes if the condition is
-	     in the form of a comparison of a register against zero.  
-	     If the condition is more complex than that, then it is safe
-	     not to record any information.  */
-	  if (REG_P (reg)
+ 	     in the form of a reversible comparison of a register against
+ 	     zero.  If the condition is more complex than that, then it is
+ 	     safe not to record any information.  */
+ 	  inv_cond = reversed_comparison_code (cond_true, BB_END (bb));
+ 	  if (inv_cond != UNKNOWN
+ 	      && REG_P (reg)
 	      && XEXP (cond_true, 1) == const0_rtx)
 	    {
 	      rtx cond_false
-		= gen_rtx_fmt_ee (reverse_condition (GET_CODE (cond_true)),
+		= gen_rtx_fmt_ee (inv_cond,
 				  GET_MODE (cond_true), XEXP (cond_true, 0),
 				  XEXP (cond_true, 1));
 	      if (GET_CODE (XEXP (set_src, 1)) == PC)