Hi DJ,
This patch contains two small improvements for the RL78 compiler:
1. A peephole to match:
movw ax, !<function_name>
movw bc, ax
call bc
with:
movw ax, !<function_name>
call ax
2. A change to avoid pushing the frame pointer register in an
interrupt handler if the handler never uses or corrupts the
frame pointer.
Tested with no regressions using an rx-elf toolchain.
OK to apply ?
Cheers
Nick
gcc/ChangeLog
2015-06-02 Nick Clifton <ni...@redhat.com>
* config/rl78/rl78-real.md: Add peepholes to avoid a register
copy when calling a function.
* config/rl78/rl78.c (need_to_save): Do not push the frame
pointer in an interrupt handler prologue if it is never used.
Index: gcc/config/rl78/rl78-real.md
===================================================================
--- gcc/config/rl78/rl78-real.md (revision 224011)
+++ gcc/config/rl78/rl78-real.md (working copy)
@@ -342,6 +342,25 @@
[(set (attr "update_Z") (const_string "clobber"))]
)
+;; Peephole to match:
+;;
+;; (set (reg1) (reg2))
+;; (call (mem (reg1)))
+;;
+;; and replace it with:
+;;
+;; (call (mem (reg2)))
+
+(define_peephole2
+ [(set (match_operand:HI 0 "register_operand") (match_operand:HI 1
"register_operand"))
+ (call (mem:HI (match_dup 0))(const_int 0))
+ ]
+ "peep2_regno_dead_p (2, REGNO (operands[0]))
+ && REGNO (operands[1]) < 8"
+ [(call (mem:HI (match_dup 1))(const_int 0))
+ ]
+)
+
(define_insn "*call_value_real"
[(set (match_operand 0 "register_operand" "=v,v")
(call (match_operand:HI 1 "memory_operand" "Wab,Wca")
@@ -353,6 +372,25 @@
[(set (attr "update_Z") (const_string "clobber"))]
)
+;; Peephole to match:
+;;
+;; (set (reg1) (reg2))
+;; (set (reg3) (call (mem (reg1))))
+;;
+;; and replace it with:
+;;
+;; (set (reg3) (call (mem (reg2))))
+
+(define_peephole2
+ [(set (match_operand:HI 0 "register_operand") (match_operand:HI 1
"register_operand"))
+ (set (match_operand:HI 2 "register_operand") (call (mem:HI (match_dup
0))(const_int 0)))
+ ]
+ "peep2_regno_dead_p (2, REGNO (operands[0]))
+ && REGNO (operands[1]) < 8"
+ [(set (match_dup 2) (call (mem:HI (match_dup 1))(const_int 0)))
+ ]
+)
+
(define_insn "*cbranchqi4_real_signed"
[(set (pc) (if_then_else
(match_operator 0 "rl78_cmp_operator_signed"
Index: gcc/config/rl78/rl78.c
===================================================================
--- gcc/config/rl78/rl78.c (revision 224011)
+++ gcc/config/rl78/rl78.c (working copy)
@@ -678,10 +678,12 @@
/* If the handler is a non-leaf function then it may call
non-interrupt aware routines which will happily clobber
- any call_used registers, so we have to preserve them. */
- if (!crtl->is_leaf && call_used_regs[regno])
+ any call_used registers, so we have to preserve them.
+ We do not have to worry about the frame pointer register
+ though, as that is handled below. */
+ if (!crtl->is_leaf && call_used_regs[regno] && regno < 22)
return true;
-
+
/* Otherwise we only have to save a register, call_used
or not, if it is used by this handler. */
return df_regs_ever_live_p (regno);
