* Claudiu Zissulescu <claz...@gmail.com> [2018-10-10 11:00:14 +0300]:
> Simple peephole rules which combines multiple ld/st instructions into
> 64-bit load/store instructions. It only works for architectures which
> are having double load/store option on.
>
> gcc/
> Claudiu Zissulescu <claz...@synopsys.com>
>
> * config/arc/arc-protos.h (gen_operands_ldd_std): Add.
> * config/arc/arc.c (operands_ok_ldd_std): New function.
> (mem_ok_for_ldd_std): Likewise.
> (gen_operands_ldd_std): Likewise.
> * config/arc/arc.md: Add peephole2 rules for std/ldd.
> ---
> gcc/config/arc/arc-protos.h | 1 +
> gcc/config/arc/arc.c | 163 ++++++++++++++++++++++++++++++++++++
> gcc/config/arc/arc.md | 67 +++++++++++++++
> 3 files changed, 231 insertions(+)
>
> diff --git a/gcc/config/arc/arc-protos.h b/gcc/config/arc/arc-protos.h
> index 24bea6e1efb..55f8ed4c643 100644
> --- a/gcc/config/arc/arc-protos.h
> +++ b/gcc/config/arc/arc-protos.h
> @@ -46,6 +46,7 @@ extern int arc_return_address_register (unsigned int);
> extern unsigned int arc_compute_function_type (struct function *);
> extern bool arc_is_uncached_mem_p (rtx);
> extern bool arc_lra_p (void);
> +extern bool gen_operands_ldd_std (rtx *operands, bool load, bool commute);
> #endif /* RTX_CODE */
>
> extern unsigned int arc_compute_frame_size (int);
> diff --git a/gcc/config/arc/arc.c b/gcc/config/arc/arc.c
> index 18dd0de6af7..9bc69e9fbc9 100644
> --- a/gcc/config/arc/arc.c
> +++ b/gcc/config/arc/arc.c
> @@ -10803,6 +10803,169 @@ arc_cannot_substitute_mem_equiv_p (rtx)
> return true;
> }
>
> +/* Checks whether the operands are valid for use in an LDD/STD
> + instruction. Assumes that RT, RT2, and RN are REG. This is
> + guaranteed by the patterns. Assumes that the address in the base
> + register RN is word aligned. Pattern guarantees that both memory
> + accesses use the same base register, the offsets are constants
> + within the range, and the gap between the offsets is 4. If preload
> + complete then check that registers are legal. WBACK indicates
> + whether address is updated. */
You've got tabs instead of whitespace inside both this comment block,
and others within this patch. It should be period and two whitespace
at the end of each sentence.
> +
> +static bool
> +operands_ok_ldd_std (rtx rt, rtx rt2, rtx rn ATTRIBUTE_UNUSED,
> + HOST_WIDE_INT offset)
Why have the RN parameter at all? I took a quick look through patches
5/6 and don't see any additional changes to this function, we should
probably just drop this at this point.
> +{
> + unsigned int t, t2;
> +
> + if (!reload_completed)
> + return true;
> +
> + if (!(SMALL_INT_RANGE (offset, (GET_MODE_SIZE (DImode) - 1) & -4,
Couldn't we use (~0x3) instead of -4? Maybe I'm just feeling slow
today, but the bit pattern for negative numbers don't just pop into my
head like those for positive numbers.
> + (offset & (GET_MODE_SIZE (DImode) - 1) & 3
> + ? 0 : -(-GET_MODE_SIZE (DImode) | -4) >> 1))))
> + return false;
> +
> + t = REGNO (rt);
> + t2 = REGNO (rt2);
> +
> + if ((t2 == 63)
Can we use PROGRAM_COUNTER_REGNO here?
> + || (t % 2 != 0) /* First destination register is not even. */
> + || (t2 != t + 1))
> + return false;
> +
> + return true;
> +}
> +
> +/* Helper for gen_operands_ldd_std. Returns true iff the memory
> + operand MEM's address contains an immediate offset from the base
> + register and has no side effects, in which case it sets BASE and
> + OFFSET accordingly. */
> +
> +static bool
> +mem_ok_for_ldd_std (rtx mem, rtx *base, rtx *offset)
> +{
> + rtx addr;
> +
> + gcc_assert (base != NULL && offset != NULL);
> +
> + /* TODO: Handle more general memory operand patterns, such as
> + PRE_DEC and PRE_INC. */
> +
> + if (side_effects_p (mem))
> + return false;
> +
> + /* Can't deal with subregs. */
> + if (GET_CODE (mem) == SUBREG)
> + return false;
> +
> + gcc_assert (MEM_P (mem));
> +
> + *offset = const0_rtx;
> +
> + addr = XEXP (mem, 0);
> +
> + /* If addr isn't valid for DImode, then we can't handle it. */
> + if (!arc_legitimate_address_p (DImode, addr,
> + reload_in_progress || reload_completed))
> + return false;
> +
> + if (REG_P (addr))
> + {
> + *base = addr;
> + return true;
> + }
> + else if (GET_CODE (addr) == PLUS || GET_CODE (addr) == MINUS)
> + {
> + *base = XEXP (addr, 0);
> + *offset = XEXP (addr, 1);
> + return (REG_P (*base) && CONST_INT_P (*offset));
> + }
> +
> + return false;
> +}
> +
> +/* Called from peephole2 to replace two word-size accesses with a
> + single LDD/STD instruction. Returns true iff we can generate a new
> + instruction sequence. That is, both accesses use the same base
> + register and the gap between constant offsets is 4. OPERANDS are
> + the operands found by the peephole matcher; OPERANDS[0,1] are
> + register operands, and OPERANDS[2,3] are the corresponding memory
> + operands. LOAD indicates whether the access is load or store. */
> +
> +bool
> +gen_operands_ldd_std (rtx *operands, bool load, bool commute)
> +{
> + int i, gap;
> + HOST_WIDE_INT offsets[2], offset;
> + int nops = 2;
> + rtx cur_base, cur_offset, tmp;
> + rtx base = NULL_RTX;
> +
> + /* Check that the memory references are immediate offsets from the
> + same base register. Extract the base register, the destination
> + registers, and the corresponding memory offsets. */
> + for (i = 0; i < nops; i++)
> + {
> + if (!mem_ok_for_ldd_std (operands[nops+i], &cur_base, &cur_offset))
> + return false;
> +
> + if (i == 0)
> + base = cur_base;
> + else if (REGNO (base) != REGNO (cur_base))
> + return false;
> +
> + offsets[i] = INTVAL (cur_offset);
> + if (GET_CODE (operands[i]) == SUBREG)
> + {
> + tmp = SUBREG_REG (operands[i]);
> + gcc_assert (GET_MODE (operands[i]) == GET_MODE (tmp));
> + operands[i] = tmp;
> + }
> + }
> +
> + /* Make sure there is no dependency between the individual loads. */
> + if (load && REGNO (operands[0]) == REGNO (base))
> + return false; /* RAW */
> +
> + if (load && REGNO (operands[0]) == REGNO (operands[1]))
> + return false; /* WAW */
> +
> + /* Make sure the instructions are ordered with lower memory access first.
> */
> + if (offsets[0] > offsets[1])
> + {
> + gap = offsets[0] - offsets[1];
> + offset = offsets[1];
> +
> + /* Swap the instructions such that lower memory is accessed first. */
> + std::swap (operands[0], operands[1]);
> + std::swap (operands[2], operands[3]);
> + }
> + else
> + {
> + gap = offsets[1] - offsets[0];
> + offset = offsets[0];
> + }
> +
> + /* Make sure accesses are to consecutive memory locations. */
> + if (gap != 4)
> + return false;
> +
> + /* Make sure we generate legal instructions. */
> + if (operands_ok_ldd_std (operands[0], operands[1], base, offset))
> + return true;
> +
> + if (load && commute)
> + {
> + /* Try reordering registers. */
> + std::swap (operands [0], operands[1]);
> + if (operands_ok_ldd_std (operands[0], operands[1], base, offset))
> + return true;
> + }
> +
> + return false;
> +}
> +
> #undef TARGET_USE_ANCHORS_FOR_SYMBOL_P
> #define TARGET_USE_ANCHORS_FOR_SYMBOL_P arc_use_anchors_for_symbol_p
>
> diff --git a/gcc/config/arc/arc.md b/gcc/config/arc/arc.md
> index 1ed230fa5f0..b968022e64a 100644
> --- a/gcc/config/arc/arc.md
> +++ b/gcc/config/arc/arc.md
> @@ -6363,6 +6363,73 @@ archs4x, archs4xd, archs4xd_slow"
> [(set (reg:CC CC_REG) (compare:CC (match_dup 3)
> (ashift:SI (match_dup 1) (match_dup 2))))])
>
> +(define_peephole2 ; std
> +[(set (match_operand:SI 2 "memory_operand" "")
> + (match_operand:SI 0 "register_operand" ""))
> + (set (match_operand:SI 3 "memory_operand" "")
> + (match_operand:SI 1 "register_operand" ""))]
> + "TARGET_LL64"
> + [(const_int 0)]
> +{
> + if (!gen_operands_ldd_std (operands, false, false))
> + FAIL;
> + operands[0] = gen_rtx_REG (DImode, REGNO (operands[0]));
> + operands[2] = adjust_address (operands[2], DImode, 0);
> + emit_insn (gen_rtx_SET (operands[2], operands[0]));
> + DONE;
> + })
> +
> +(define_peephole2 ; ldd
> + [(set (match_operand:SI 0 "register_operand" "")
> + (match_operand:SI 2 "memory_operand" ""))
> + (set (match_operand:SI 1 "register_operand" "")
> + (match_operand:SI 3 "memory_operand" ""))]
> + "TARGET_LL64"
> + [(const_int 0)]
> +{
> + if (!gen_operands_ldd_std (operands, true, false))
> + FAIL;
> + operands[0] = gen_rtx_REG (DImode, REGNO (operands[0]));
> + operands[2] = adjust_address (operands[2], DImode, 0);
> + emit_insn (gen_rtx_SET (operands[0], operands[2]));
> + DONE;
> +})
> +
> +;; We require consecutive registers for LDD instruction. Check if we
> +;; can reorder them and use an LDD.
> +
> +(define_peephole2 ; swap the destination registers of two loads
> + ; before a commutative operation.
> + [(set (match_operand:SI 0 "register_operand" "")
> + (match_operand:SI 2 "memory_operand" ""))
> + (set (match_operand:SI 1 "register_operand" "")
> + (match_operand:SI 3 "memory_operand" ""))
> + (set (match_operand:SI 4 "register_operand" "")
> + (match_operator:SI 5 "commutative_operator"
> + [(match_operand 6 "register_operand" "")
> + (match_operand 7 "register_operand" "") ]))]
> + "TARGET_LL64
> + && (((rtx_equal_p(operands[0], operands[6]))
> + && (rtx_equal_p(operands[1], operands[7])))
> + || ((rtx_equal_p(operands[0], operands[7]))
> + && (rtx_equal_p(operands[1], operands[6]))))
> + && (peep2_reg_dead_p (3, operands[0]) || rtx_equal_p (operands[0],
> operands[4]))
> + && (peep2_reg_dead_p (3, operands[1]) || rtx_equal_p (operands[1],
> operands[4]))"
> + [(set (match_dup 0) (match_dup 2))
> + (set (match_dup 4) (match_op_dup 5 [(match_dup 6) (match_dup 7)]))]
> + {
> + if (!gen_operands_ldd_std (operands, true, true))
> + {
> + FAIL;
> + }
> + else
> + {
> + operands[0] = gen_rtx_REG (DImode, REGNO (operands[0]));
> + operands[2] = adjust_address (operands[2], DImode, 0);
> + }
> + }
> +)
> +
> ;; include the arc-FPX instructions
> (include "fpx.md")
>
> --
> 2.17.1
>
