This is the mail archive of the
gcc-patches@gcc.gnu.org
mailing list for the GCC project.
[patch] h8300.md: Add a new peephole2.
- From: Kazu Hirata <kazu at cs dot umass dot edu>
- To: gcc-patches at gcc dot gnu dot org
- Date: Mon, 31 Mar 2003 05:19:29 -0500 (EST)
- Subject: [patch] h8300.md: Add a new peephole2.
Hi,
Attached is a patch to add a new peephole2.
The new peephole2 transforms
cmp.w #1,r2 ; (compare (reg:HI) (const_int 1))
bhi .L8 ; jump if (reg:HI) > (const_int 1)
into
shlr.w r2 ; (lshiftrt (reg:HI) (const_int 1))
bne .L8 ; jump if nonzero
saving 2 bytes. Similar optimization is possible for (const_int 3) on
H8S because it has 2-bit shift instructions.
Tested on h8300 port. Committed.
Kazu Hirata
2003-03-31 Kazu Hirata <kazu at cs dot umass dot edu>
* config/h8300/h8300.md (a new peephole2): New.
Index: h8300.md
===================================================================
RCS file: /cvs/gcc/gcc/gcc/config/h8300/h8300.md,v
retrieving revision 1.206
diff -u -r1.206 h8300.md
--- h8300.md 30 Mar 2003 13:00:32 -0000 1.206
+++ h8300.md 30 Mar 2003 23:00:10 -0000
@@ -3955,6 +3955,50 @@
"operands[3] = gen_lowpart (HImode, operands[0]);
operands[4] = gen_lowpart (HImode, operands[1]);")
+;; (compare (reg:HI) (const_int)) takes 4 bytes, so we try to achieve
+;; the equivalent with shorter sequences. Here is the summary. Cases
+;; are grouped for each define_peephole2.
+;;
+;; reg const_int use insn
+;; --------------------------------------------------------
+;; dead -2 eq/ne inc.l
+;; dead -1 eq/ne inc.l
+;; dead 1 eq/ne dec.l
+;; dead 2 eq/ne dec.l
+;;
+;; dead 1 geu/ltu shlr.l
+;; dead 3 (H8S) geu/ltu shlr.l
+;;
+;; dead 255 geu/ltu mov.b
+
+(define_peephole2
+ [(set (cc0)
+ (compare (match_operand:HI 0 "register_operand" "")
+ (match_operand:HI 1 "const_int_operand" "")))
+ (set (pc)
+ (if_then_else (match_operator 2 "gtuleu_operator"
+ [(cc0) (const_int 0)])
+ (label_ref (match_operand 3 "" ""))
+ (pc)))]
+ "(TARGET_H8300H || TARGET_H8300S)
+ && peep2_reg_dead_p (1, operands[0])
+ && (INTVAL (operands[1]) == 1
+ || (TARGET_H8300S && INTVAL (operands[1]) == 3))"
+ [(parallel [(set (match_dup 0)
+ (lshiftrt:HI (match_dup 0)
+ (match_dup 5)))
+ (clobber (scratch:QI))])
+ (set (cc0)
+ (match_dup 0))
+ (set (pc)
+ (if_then_else (match_dup 4)
+ (label_ref (match_dup 3))
+ (pc)))]
+ "operands[4] = ((GET_CODE (operands[2]) == GTU) ?
+ gen_rtx_NE (VOIDmode, cc0_rtx, const0_rtx) :
+ gen_rtx_EQ (VOIDmode, cc0_rtx, const0_rtx));
+ operands[5] = GEN_INT (exact_log2 (INTVAL (operands[1]) + 1));")
+
;; (compare (reg:SI) (const_int)) takes 6 bytes, so we try to achieve
;; the equivalent with shorter sequences. Here is the summary. Cases
;; are grouped for each define_peephole2.