[4/6,ARC] Add peephole rules to combine store/loads into double store/loads

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  <claziss@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(+)

* Claudiu Zissulescu <claziss@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  <claziss@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
>

On 22 October 2018 19:49:35 CEST, Andrew Burgess <andrew.burgess@embecosm.com> wrote:
>* Claudiu Zissulescu <claziss@gmail.com> [2018-10-10 11:00:14 +0300]:

>> --- 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.

See contrib/check_GNU_style.py

Also:

s/If preload/If reload/

thanks,

Thank you for your review. Please find attached a new respin patch with
your feedback in.

Please let me know if it is ok,
Claudiu
From 4ff7d8419783eceeffbaf27df017d0a93c3af942 Mon Sep 17 00:00:00 2001
From: Claudiu Zissulescu <claziss@gmail.com>
Date: Thu, 9 Aug 2018 14:29:05 +0300
Subject: [PATCH] [ARC] Add peephole rules to combine store/loads into double
 store/loads

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  <claziss@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        | 161 ++++++++++++++++++++++++++++++++++++
 gcc/config/arc/arc.md       |  69 ++++++++++++++++
 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..daf785dbdb8 100644
--- a/gcc/config/arc/arc.c
+++ b/gcc/config/arc/arc.c
@@ -10803,6 +10803,167 @@ 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, and RT2 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 reload complete then
+   check that registers are legal.  */
+
+static bool
+operands_ok_ldd_std (rtx rt, rtx rt2, HOST_WIDE_INT offset)
+{
+  unsigned int t, t2;
+
+  if (!reload_completed)
+    return true;
+
+  if (!(SMALL_INT_RANGE (offset, (GET_MODE_SIZE (DImode) - 1) & (~0x03),
+			 (offset & (GET_MODE_SIZE (DImode) - 1) & 3
+			  ? 0 : -(-GET_MODE_SIZE (DImode) | (~0x03)) >> 1))))
+    return false;
+
+  t = REGNO (rt);
+  t2 = REGNO (rt2);
+
+  if ((t2 == PROGRAM_COUNTER_REGNO)
+      || (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], offset))
+    return true;
+
+  if (load && commute)
+    {
+      /* Try reordering registers.  */
+      std::swap (operands[0], operands[1]);
+      if (operands_ok_ldd_std (operands[0], operands[1], 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..526fd17a0cf 100644
--- a/gcc/config/arc/arc.md
+++ b/gcc/config/arc/arc.md
@@ -6363,6 +6363,75 @@ 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")

PING.

On Wed, 2018-10-31 at 10:33 +0200, claziss@gmail.com wrote:
> Thank you for your review. Please find attached a new respin patch
> with
> your feedback in.
> 
> Please let me know if it is ok,
> Claudiu

* claziss@gmail.com <claziss@gmail.com> [2018-10-31 10:33:33 +0200]:

> Thank you for your review. Please find attached a new respin patch with
> your feedback in.
> 
> Please let me know if it is ok,
> Claudiu 

> From 4ff7d8419783eceeffbaf27df017d0a93c3af942 Mon Sep 17 00:00:00 2001
> From: Claudiu Zissulescu <claziss@gmail.com>
> Date: Thu, 9 Aug 2018 14:29:05 +0300
> Subject: [PATCH] [ARC] Add peephole rules to combine store/loads into double
>  store/loads
> 
> 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  <claziss@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.

Looks good.

Thanks,
Andrew


> ---
>  gcc/config/arc/arc-protos.h |   1 +
>  gcc/config/arc/arc.c        | 161 ++++++++++++++++++++++++++++++++++++
>  gcc/config/arc/arc.md       |  69 ++++++++++++++++
>  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..daf785dbdb8 100644
> --- a/gcc/config/arc/arc.c
> +++ b/gcc/config/arc/arc.c
> @@ -10803,6 +10803,167 @@ 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, and RT2 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 reload complete then
> +   check that registers are legal.  */
> +
> +static bool
> +operands_ok_ldd_std (rtx rt, rtx rt2, HOST_WIDE_INT offset)
> +{
> +  unsigned int t, t2;
> +
> +  if (!reload_completed)
> +    return true;
> +
> +  if (!(SMALL_INT_RANGE (offset, (GET_MODE_SIZE (DImode) - 1) & (~0x03),
> +			 (offset & (GET_MODE_SIZE (DImode) - 1) & 3
> +			  ? 0 : -(-GET_MODE_SIZE (DImode) | (~0x03)) >> 1))))
> +    return false;
> +
> +  t = REGNO (rt);
> +  t2 = REGNO (rt2);
> +
> +  if ((t2 == PROGRAM_COUNTER_REGNO)
> +      || (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], offset))
> +    return true;
> +
> +  if (load && commute)
> +    {
> +      /* Try reordering registers.  */
> +      std::swap (operands[0], operands[1]);
> +      if (operands_ok_ldd_std (operands[0], operands[1], 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..526fd17a0cf 100644
> --- a/gcc/config/arc/arc.md
> +++ b/gcc/config/arc/arc.md
> @@ -6363,6 +6363,75 @@ 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
>