Hi, This patch cleans up by_pieces_ninsns and does following things. 1. Do the length and alignment adjustment for by pieces compare when overlap operation is enabled. 2. Remove unnecessary mov_optab checks.
Bootstrapped and tested on x86 and powerpc64-linux BE and LE with no regressions. Is this OK for trunk? Thanks Gui Haochen ChangeLog Clean up by_pieces_ninsns The by pieces compare can be implemented by overlapped operations. So it should be taken into consideration when doing the adjustment for overlap operations. The mode returned from widest_fixed_size_mode_for_size is already checked with mov_optab in by_pieces_mode_supported_p called by widest_fixed_size_mode_for_size. So there is no need to check mov_optab again in by_pieces_ninsns. The patch fixes these issues. gcc/ * expr.cc (by_pieces_ninsns): Include by pieces compare when do the adjustment for overlap operations. Remove unnecessary mov_optab check. patch.diff diff --git a/gcc/expr.cc b/gcc/expr.cc index 3e2a678710d..7cb2c935177 100644 --- a/gcc/expr.cc +++ b/gcc/expr.cc @@ -1090,18 +1090,15 @@ by_pieces_ninsns (unsigned HOST_WIDE_INT l, unsigned int align, unsigned HOST_WIDE_INT n_insns = 0; fixed_size_mode mode; - if (targetm.overlap_op_by_pieces_p () && op != COMPARE_BY_PIECES) + if (targetm.overlap_op_by_pieces_p ()) { /* NB: Round up L and ALIGN to the widest integer mode for MAX_SIZE. */ mode = widest_fixed_size_mode_for_size (max_size, op); - if (optab_handler (mov_optab, mode) != CODE_FOR_nothing) - { - unsigned HOST_WIDE_INT up = ROUND_UP (l, GET_MODE_SIZE (mode)); - if (up > l) - l = up; - align = GET_MODE_ALIGNMENT (mode); - } + unsigned HOST_WIDE_INT up = ROUND_UP (l, GET_MODE_SIZE (mode)); + if (up > l) + l = up; + align = GET_MODE_ALIGNMENT (mode); } align = alignment_for_piecewise_move (MOVE_MAX_PIECES, align); @@ -1109,12 +1106,10 @@ by_pieces_ninsns (unsigned HOST_WIDE_INT l, unsigned int align, while (max_size > 1 && l > 0) { mode = widest_fixed_size_mode_for_size (max_size, op); - enum insn_code icode; unsigned int modesize = GET_MODE_SIZE (mode); - icode = optab_handler (mov_optab, mode); - if (icode != CODE_FOR_nothing && align >= GET_MODE_ALIGNMENT (mode)) + if (align >= GET_MODE_ALIGNMENT (mode)) { unsigned HOST_WIDE_INT n_pieces = l / modesize; l %= modesize;