re PR target/49903 ([avr] Redundant comparisons in binary-search switch/case expansion)

	
	* PR target/49903
	* config/avr/avr.md (UNSPEC_IDENTITY): New c_enum.
	(branch_unspec): New insn.
	(branch): Beauty farm.
	* config/avr/avr.c (compare_condition): Use JUMP_P.  Test SET_SRC
	to be IF_THEN_ELSE.
	(avr_compare_pattern, avr_reorg_remove_redundant_compare):
	New static functions.
	(avr_reorg): Use them.  Use next_real_insn instead of NEXT_INSN.
	Use CONST_INT_P.  Beauty.

From-SVN: r177744

gcc/ChangeLog

+2011-08-14  Georg-Johann Lay  <avr@gjlay.de>
+	
+	* PR target/49903
+	* config/avr/avr.md (UNSPEC_IDENTITY): New c_enum.
+	(branch_unspec): New insn.
+	(branch): Beauty farm.
+	* config/avr/avr.c (compare_condition): Use JUMP_P.  Test SET_SRC
+	to be IF_THEN_ELSE.
+	(avr_compare_pattern, avr_reorg_remove_redundant_compare):
+	New static functions.
+	(avr_reorg): Use them.  Use next_real_insn instead of NEXT_INSN.
+	Use CONST_INT_P.  Beauty.
+
 2011-08-12  David Li  <davidxl@google.com>
 
 	* cp/class.c (update_vtable_entry_for_fn): Set

gcc/config/avr/avr.md

@@ -56,6 +56,7 @@
    UNSPEC_FMULS
    UNSPEC_FMULSU
    UNSPEC_COPYSIGN
+   UNSPEC_IDENTITY
    ])
 
 (define_c_enum "unspecv"
@@ -3339,16 +3340,36 @@
 (define_insn "branch"
   [(set (pc)
         (if_then_else (match_operator 1 "simple_comparison_operator"
-                        [(cc0)
-                         (const_int 0)])
+                                      [(cc0)
+                                       (const_int 0)])
                       (label_ref (match_operand 0 "" ""))
                       (pc)))]
   ""
-  "*
-   return ret_cond_branch (operands[1], avr_jump_mode (operands[0],insn), 0);"
+  {
+    return ret_cond_branch (operands[1], avr_jump_mode (operands[0], insn), 0);
+  }
   [(set_attr "type" "branch")
    (set_attr "cc" "clobber")])
 
+
+;; Same as above but wrap SET_SRC so that this branch won't be transformed
+;; or optimized in the remainder.
+
+(define_insn "branch_unspec"
+  [(set (pc)
+        (unspec [(if_then_else (match_operator 1 "simple_comparison_operator"
+                                               [(cc0)
+                                                (const_int 0)])
+                               (label_ref (match_operand 0 "" ""))
+                               (pc))
+                 ] UNSPEC_IDENTITY))]
+  ""
+  {
+    return ret_cond_branch (operands[1], avr_jump_mode (operands[0], insn), 0);
+  }
+  [(set_attr "type" "branch")
+   (set_attr "cc" "none")])
+
 ;; ****************************************************************
 ;; AVR does not have following conditional jumps: LE,LEU,GT,GTU.
 ;; Convert them all to proper jumps.