Until now, we applied COSTS_N_INSNS() (multiplying by 4) after dividing the instruction length by 3, so we couldn't express the difference less than modulo 3 in insn cost for size (e.g. 11 Bytes and 12 bytes cost the same).
This patch fixes that. ;; 2 bytes addi.n a2, a2, -1 ; cost 3 ;; 3 bytes addmi a2, a2, 1024 ; cost 4 ;; 4 bytes movi.n a3, 80 ; cost 5 bnez.n a2, a3, .L4 ;; 5 bytes srli a2, a3, 1 ; cost 7 add.n a2, a2, a2 ;; 6 bytes ssai 8 ; cost 8 src a4, a2, a3 :: 3 + 4 bytes l32r a2, .L5 ; cost 9 ;; 11 bytes ; cost 15 ;; 12 bytes ; cost 16 gcc/ChangeLog: * config/xtensa/xtensa.cc (xtensa_insn_cost): Let insn cost for size be obtained by applying COSTS_N_INSNS() to instruction length and then dividing by 3. --- gcc/config/xtensa/xtensa.cc | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/gcc/config/xtensa/xtensa.cc b/gcc/config/xtensa/xtensa.cc index a1f184950ae..6cf6b35399a 100644 --- a/gcc/config/xtensa/xtensa.cc +++ b/gcc/config/xtensa/xtensa.cc @@ -4519,13 +4519,15 @@ xtensa_insn_cost (rtx_insn *insn, bool speed) { if (!(recog_memoized (insn) < 0)) { - int len = get_attr_length (insn), n = (len + 2) / 3; + int len = get_attr_length (insn); if (len == 0) return COSTS_N_INSNS (0); if (speed) /* For speed cost. */ { + int n = (len + 2) / 3; + /* "L32R" may be particular slow (implementation-dependent). */ if (xtensa_is_insn_L32R_p (insn)) return COSTS_N_INSNS (1 + xtensa_extra_l32r_costs); @@ -4572,10 +4574,11 @@ xtensa_insn_cost (rtx_insn *insn, bool speed) { /* "L32R" itself plus constant in litpool. */ if (xtensa_is_insn_L32R_p (insn)) - return COSTS_N_INSNS (2) + 1; + len = 3 + 4; - /* Consider ".n" short instructions. */ - return COSTS_N_INSNS (n) - (n * 3 - len); + /* Consider fractional instruction length (for example, ".n" + short instructions or "L32R" litpool constants. */ + return (COSTS_N_INSNS (len) + 1) / 3; } } } -- 2.30.2