On 20/07/16 14:02, Jiong Wang wrote:
> Currently aarch64_add_constant is using aarch64_build_constant to move
> an immediate into the destination register.
>
> It has considered the following situations:
>
> * immediate can fit into bitmask pattern that only needs single
> instruction.
> * immediate can fit into single movz/movn.
> * immediate needs single movz/movn, and multiply movk.
>
>
> Actually we have another constant building helper function
> "aarch64_internal_mov_immediate" which cover all these situations and
> more.
>
> This patch thus migrate aarch64_add_constant to
> aarch64_internal_mov_immediate so that we can kill the old
> aarch64_build_constant.
>
> OK for trunk?
>
> gcc/
> 2016-07-20 Jiong Wang <jiong.w...@arm.com>
>
> * config/aarch64/aarch64.c (aarch64_add_constant): New
> parameter "mode". Use aarch64_internal_mov_immediate
> instead of aarch64_build_constant.
> (aarch64_build_constant): Delete.
>
Really you should also list the callers of aarch64_add_constant that
have been updated as well (there aren't that many).
OK with that change.
R.
>
> build-const-1.patch
>
>
> diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c
> index
> 512ef10d158d2eaa1384d28c43b9a8f90387099d..aeea3b3ebc514663043ac8d7cd13361f06f78502
> 100644
> --- a/gcc/config/aarch64/aarch64.c
> +++ b/gcc/config/aarch64/aarch64.c
> @@ -3337,98 +3337,20 @@ aarch64_final_eh_return_addr (void)
> - 2 * UNITS_PER_WORD));
> }
>
> -/* Possibly output code to build up a constant in a register. For
> - the benefit of the costs infrastructure, returns the number of
> - instructions which would be emitted. GENERATE inhibits or
> - enables code generation. */
> -
> -static int
> -aarch64_build_constant (int regnum, HOST_WIDE_INT val, bool generate)
> -{
> - int insns = 0;
> -
> - if (aarch64_bitmask_imm (val, DImode))
> - {
> - if (generate)
> - emit_move_insn (gen_rtx_REG (Pmode, regnum), GEN_INT (val));
> - insns = 1;
> - }
> - else
> - {
> - int i;
> - int ncount = 0;
> - int zcount = 0;
> - HOST_WIDE_INT valp = val >> 16;
> - HOST_WIDE_INT valm;
> - HOST_WIDE_INT tval;
> -
> - for (i = 16; i < 64; i += 16)
> - {
> - valm = (valp & 0xffff);
> -
> - if (valm != 0)
> - ++ zcount;
> -
> - if (valm != 0xffff)
> - ++ ncount;
> -
> - valp >>= 16;
> - }
> -
> - /* zcount contains the number of additional MOVK instructions
> - required if the constant is built up with an initial MOVZ instruction,
> - while ncount is the number of MOVK instructions required if starting
> - with a MOVN instruction. Choose the sequence that yields the fewest
> - number of instructions, preferring MOVZ instructions when they are both
> - the same. */
> - if (ncount < zcount)
> - {
> - if (generate)
> - emit_move_insn (gen_rtx_REG (Pmode, regnum),
> - GEN_INT (val | ~(HOST_WIDE_INT) 0xffff));
> - tval = 0xffff;
> - insns++;
> - }
> - else
> - {
> - if (generate)
> - emit_move_insn (gen_rtx_REG (Pmode, regnum),
> - GEN_INT (val & 0xffff));
> - tval = 0;
> - insns++;
> - }
> -
> - val >>= 16;
> -
> - for (i = 16; i < 64; i += 16)
> - {
> - if ((val & 0xffff) != tval)
> - {
> - if (generate)
> - emit_insn (gen_insv_immdi (gen_rtx_REG (Pmode, regnum),
> - GEN_INT (i),
> - GEN_INT (val & 0xffff)));
> - insns++;
> - }
> - val >>= 16;
> - }
> - }
> - return insns;
> -}
> -
> static void
> -aarch64_add_constant (int regnum, int scratchreg, HOST_WIDE_INT delta)
> +aarch64_add_constant (machine_mode mode, int regnum, int scratchreg,
> + HOST_WIDE_INT delta)
> {
> HOST_WIDE_INT mdelta = delta;
> - rtx this_rtx = gen_rtx_REG (Pmode, regnum);
> - rtx scratch_rtx = gen_rtx_REG (Pmode, scratchreg);
> + rtx this_rtx = gen_rtx_REG (mode, regnum);
> + rtx scratch_rtx = gen_rtx_REG (mode, scratchreg);
>
> if (mdelta < 0)
> mdelta = -mdelta;
>
> if (mdelta >= 4096 * 4096)
> {
> - (void) aarch64_build_constant (scratchreg, delta, true);
> + aarch64_internal_mov_immediate (scratch_rtx, GEN_INT (delta), true,
> mode);
> emit_insn (gen_add3_insn (this_rtx, this_rtx, scratch_rtx));
> }
> else if (mdelta > 0)
> @@ -3436,19 +3358,19 @@ aarch64_add_constant (int regnum, int scratchreg,
> HOST_WIDE_INT delta)
> if (mdelta >= 4096)
> {
> emit_insn (gen_rtx_SET (scratch_rtx, GEN_INT (mdelta / 4096)));
> - rtx shift = gen_rtx_ASHIFT (Pmode, scratch_rtx, GEN_INT (12));
> + rtx shift = gen_rtx_ASHIFT (mode, scratch_rtx, GEN_INT (12));
> if (delta < 0)
> emit_insn (gen_rtx_SET (this_rtx,
> - gen_rtx_MINUS (Pmode, this_rtx, shift)));
> + gen_rtx_MINUS (mode, this_rtx, shift)));
> else
> emit_insn (gen_rtx_SET (this_rtx,
> - gen_rtx_PLUS (Pmode, this_rtx, shift)));
> + gen_rtx_PLUS (mode, this_rtx, shift)));
> }
> if (mdelta % 4096 != 0)
> {
> scratch_rtx = GEN_INT ((delta < 0 ? -1 : 1) * (mdelta % 4096));
> emit_insn (gen_rtx_SET (this_rtx,
> - gen_rtx_PLUS (Pmode, this_rtx, scratch_rtx)));
> + gen_rtx_PLUS (mode, this_rtx, scratch_rtx)));
> }
> }
> }
> @@ -3473,7 +3395,7 @@ aarch64_output_mi_thunk (FILE *file, tree thunk
> ATTRIBUTE_UNUSED,
> emit_note (NOTE_INSN_PROLOGUE_END);
>
> if (vcall_offset == 0)
> - aarch64_add_constant (this_regno, IP1_REGNUM, delta);
> + aarch64_add_constant (Pmode, this_regno, IP1_REGNUM, delta);
> else
> {
> gcc_assert ((vcall_offset & (POINTER_BYTES - 1)) == 0);
> @@ -3489,7 +3411,7 @@ aarch64_output_mi_thunk (FILE *file, tree thunk
> ATTRIBUTE_UNUSED,
> addr = gen_rtx_PRE_MODIFY (Pmode, this_rtx,
> plus_constant (Pmode, this_rtx, delta));
> else
> - aarch64_add_constant (this_regno, IP1_REGNUM, delta);
> + aarch64_add_constant (Pmode, this_regno, IP1_REGNUM, delta);
> }
>
> if (Pmode == ptr_mode)
> @@ -3503,7 +3425,8 @@ aarch64_output_mi_thunk (FILE *file, tree thunk
> ATTRIBUTE_UNUSED,
> addr = plus_constant (Pmode, temp0, vcall_offset);
> else
> {
> - (void) aarch64_build_constant (IP1_REGNUM, vcall_offset, true);
> + aarch64_internal_mov_immediate (temp1, GEN_INT (vcall_offset), true,
> + Pmode);
> addr = gen_rtx_PLUS (Pmode, temp0, temp1);
> }
>
>
