Hi Guys,
I am applying the patch below to add a couple of peephole
optimizations to the RX backend. It seems that GCC does not cope very
well with the RX's ability to perform either sign-extending loads or
zero-extending loads and so sometimes it can generate an extending
load followed by a register to register extension. The peepholes
match these cases and delete the unnecessary extension where possible.
Cheers
Nick
gcc/ChangeLog
2011-05-17 Nick Clifton <ni...@redhat.com>
* config/rx/rx.md: Add peephole to remove redundant extensions
after loads.
Index: gcc/config/rx/rx.md
===================================================================
--- gcc/config/rx/rx.md (revision 173819)
+++ gcc/config/rx/rx.md (working copy)
@@ -1701,6 +1701,35 @@
(extend_types:SI (match_dup 1))))]
)
+;; Convert:
+;; (set (reg1) (sign_extend (mem))
+;; (set (reg2) (zero_extend (reg1))
+;; into
+;; (set (reg2) (zero_extend (mem)))
+(define_peephole2
+ [(set (match_operand:SI 0 "register_operand")
+ (sign_extend:SI (match_operand:small_int_modes 1 "memory_operand")))
+ (set (match_operand:SI 2 "register_operand")
+ (zero_extend:SI (match_operand:small_int_modes 3 "register_operand")))]
+ "REGNO (operands[0]) == REGNO (operands[3])
+ && (REGNO (operands[0]) == REGNO (operands[2])
+ || peep2_regno_dead_p (2, REGNO (operands[0])))"
+ [(set (match_dup 2)
+ (zero_extend:SI (match_dup 1)))]
+)
+
+;; Remove the redundant sign extension from:
+;; (set (reg) (extend (mem)))
+;; (set (reg) (extend (reg)))
+(define_peephole2
+ [(set (match_operand:SI 0 "register_operand")
+ (extend_types:SI (match_operand:small_int_modes 1 "memory_operand")))
+ (set (match_dup 0)
+ (extend_types:SI (match_operand:small_int_modes 2 "register_operand")))]
+ "REGNO (operands[0]) == REGNO (operands[2])"
+ [(set (match_dup 0) (extend_types:SI (match_dup 1)))]
+)
+
(define_insn "comparesi3_<extend_types:code><small_int_modes:mode>"
[(set (reg:CC CC_REG)
(compare:CC (match_operand:SI 0
"register_operand" "=r")
