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From: Jackson Woodruff <jackson.woodruff@foss.arm.com>
To: "Richard Earnshaw (lists)" <Richard.Earnshaw@arm.com>,
	gcc-patches@gcc.gnu.org
Cc: James Greenhalgh <james.greenhalgh@arm.com>
Subject: Re: [AArch64, PATCH] Improve Neon store of zero
Date: Wed, 16 Aug 2017 16:01:00 -0000	[thread overview]
Message-ID: <f7e9a7ec-b2d5-dcdd-d67b-e6f246385738@foss.arm.com> (raw)
In-Reply-To: <02cb536e-0214-ae4f-df22-d18a82087990@arm.com>

[-- Attachment #1: Type: text/plain, Size: 6194 bytes --]

Hi Richard,

I have changed the condition as you suggest below. OK for trunk?

Jackson.

On 08/11/2017 02:56 PM, Richard Earnshaw (lists) wrote:

> On 10/08/17 14:12, Jackson Woodruff wrote:
>> Hi all,
>>
>> This patch changes patterns in aarch64-simd.md to replace
>>
>>      movi    v0.4s, 0
>>      str    q0, [x0, 16]
>>
>> With:
>>
>>      stp xzr, xzr, [x0, 16]
>>
>> When we are storing zeros to vectors like this:
>>
>>      void f(uint32x4_t *p) {
>>        uint32x4_t x = { 0, 0, 0, 0};
>>        p[1] = x;
>>      }
>>
>> Bootstrapped and regtested on aarch64 with no regressions.
>> OK for trunk?
>>
>> Jackson
>>
>> gcc/
>>
>> 2017-08-09  Jackson Woodruff  <jackson.woodruff@arm.com>
>>
>>      * aarch64-simd.md (mov<mode>): No longer force zero
>>      immediate into register.
>>      (*aarch64_simd_mov<mode>): Add new case for stp
>>      using zero immediate.
>>
>>
>> gcc/testsuite
>>
>> 2017-08-09  Jackson Woodruff  <jackson.woodruff@arm.com>
>>
>>      * gcc.target/aarch64/simd/neon_str_zero.c: New.
>>
>>
>> patchfile
>>
>>
>> diff --git a/gcc/config/aarch64/aarch64-simd.md b/gcc/config/aarch64/aarch64-simd.md
>> index 74de9b8c89dd5e4e3d87504594c969de0e0128ce..0149a742d34ae4fd5b3fd705b03c845f94aa1d59 100644
>> --- a/gcc/config/aarch64/aarch64-simd.md
>> +++ b/gcc/config/aarch64/aarch64-simd.md
>> @@ -23,7 +23,10 @@
>>   	(match_operand:VALL_F16 1 "general_operand" ""))]
>>     "TARGET_SIMD"
>>     "
>> -    if (GET_CODE (operands[0]) == MEM)
>> +    if (GET_CODE (operands[0]) == MEM
>> +	    && !(aarch64_simd_imm_zero (operands[1], <MODE>mode)
>> +		 && aarch64_legitimate_address_p (<MODE>mode, operands[0],
>> +						  PARALLEL, 1)))
>>         operands[1] = force_reg (<MODE>mode, operands[1]);
>>     "
>>   )
>> @@ -94,63 +97,70 @@
>>   
>>   (define_insn "*aarch64_simd_mov<mode>"
>>     [(set (match_operand:VD 0 "nonimmediate_operand"
>> -		"=w, m,  w, ?r, ?w, ?r, w")
>> +		"=w, m,  m,  w, ?r, ?w, ?r, w")
>>   	(match_operand:VD 1 "general_operand"
>> -		"m,  w,  w,  w,  r,  r, Dn"))]
>> +		"m,  Dz, w,  w,  w,  r,  r, Dn"))]
>>     "TARGET_SIMD
>> -   && (register_operand (operands[0], <MODE>mode)
>> -       || register_operand (operands[1], <MODE>mode))"
>> +   && ((register_operand (operands[0], <MODE>mode)
>> +       || register_operand (operands[1], <MODE>mode))
>> +      || (memory_operand (operands[0], <MODE>mode)
>> +	  && immediate_operand (operands[1], <MODE>mode)))"
> Allowing any immediate here seems too lax - it allows any immediate
> value which then could cause reload operations to be inserted (that in
> turn might cause register pressure calculations to be incorrect).
> Wouldn't it be better to use something like aarch64_simd_reg_or_zero?
> Similarly below.
>
> R.
>
>>   {
>>      switch (which_alternative)
>>        {
>>        case 0: return "ldr\\t%d0, %1";
>> -     case 1: return "str\\t%d1, %0";
>> -     case 2: return "mov\t%0.<Vbtype>, %1.<Vbtype>";
>> -     case 3: return "umov\t%0, %1.d[0]";
>> -     case 4: return "fmov\t%d0, %1";
>> -     case 5: return "mov\t%0, %1";
>> -     case 6:
>> +     case 1: return "str\\txzr, %0";
>> +     case 2: return "str\\t%d1, %0";
>> +     case 3: return "mov\t%0.<Vbtype>, %1.<Vbtype>";
>> +     case 4: return "umov\t%0, %1.d[0]";
>> +     case 5: return "fmov\t%d0, %1";
>> +     case 6: return "mov\t%0, %1";
>> +     case 7:
>>   	return aarch64_output_simd_mov_immediate (operands[1],
>>   						  <MODE>mode, 64);
>>        default: gcc_unreachable ();
>>        }
>>   }
>> -  [(set_attr "type" "neon_load1_1reg<q>, neon_store1_1reg<q>,\
>> +  [(set_attr "type" "neon_load1_1reg<q>, neon_stp, neon_store1_1reg<q>,\
>>   		     neon_logic<q>, neon_to_gp<q>, f_mcr,\
>>   		     mov_reg, neon_move<q>")]
>>   )
>>   
>>   (define_insn "*aarch64_simd_mov<mode>"
>>     [(set (match_operand:VQ 0 "nonimmediate_operand"
>> -		"=w, m,  w, ?r, ?w, ?r, w")
>> +		"=w, Ump,  m,  w, ?r, ?w, ?r, w")
>>   	(match_operand:VQ 1 "general_operand"
>> -		"m,  w,  w,  w,  r,  r, Dn"))]
>> +		"m,  Dz, w,  w,  w,  r,  r, Dn"))]
>>     "TARGET_SIMD
>> -   && (register_operand (operands[0], <MODE>mode)
>> -       || register_operand (operands[1], <MODE>mode))"
>> +   && ((register_operand (operands[0], <MODE>mode)
>> +	|| register_operand (operands[1], <MODE>mode))
>> +       || (memory_operand (operands[0], <MODE>mode)
>> +	   && immediate_operand (operands[1], <MODE>mode)))"
>>   {
>>     switch (which_alternative)
>>       {
>>       case 0:
>>   	return "ldr\\t%q0, %1";
>>       case 1:
>> -	return "str\\t%q1, %0";
>> +	return "stp\\txzr, xzr, %0";
>>       case 2:
>> -	return "mov\t%0.<Vbtype>, %1.<Vbtype>";
>> +	return "str\\t%q1, %0";
>>       case 3:
>> +	return "mov\t%0.<Vbtype>, %1.<Vbtype>";
>>       case 4:
>>       case 5:
>> -	return "#";
>>       case 6:
>> +	return "#";
>> +    case 7:
>>   	return aarch64_output_simd_mov_immediate (operands[1], <MODE>mode, 128);
>>       default:
>>   	gcc_unreachable ();
>>       }
>>   }
>>     [(set_attr "type" "neon_load1_1reg<q>, neon_store1_1reg<q>,\
>> -                     neon_logic<q>, multiple, multiple, multiple,\
>> -                     neon_move<q>")
>> -   (set_attr "length" "4,4,4,8,8,8,4")]
>> +		     neon_stp, neon_logic<q>, multiple, multiple,\
>> +		     multiple, neon_move<q>")
>> +   (set_attr "length" "4,4,4,4,8,8,8,4")]
>>   )
>>   
>>   ;; When storing lane zero we can use the normal STR and its more permissive
>> diff --git a/gcc/testsuite/gcc.target/aarch64/simd/neon_str_zero.c b/gcc/testsuite/gcc.target/aarch64/simd/neon_str_zero.c
>> new file mode 100644
>> index 0000000000000000000000000000000000000000..07198de109432b530745cc540790303ae0245efb
>> --- /dev/null
>> +++ b/gcc/testsuite/gcc.target/aarch64/simd/neon_str_zero.c
>> @@ -0,0 +1,22 @@
>> +/* { dg-do compile } */
>> +/* { dg-options "-O1" } */
>> +
>> +#include <arm_neon.h>
>> +
>> +void
>> +f (uint32x4_t *p)
>> +{
>> +  uint32x4_t x = { 0, 0, 0, 0};
>> +  p[1] = x;
>> +
>> +  /* { dg-final { scan-assembler "stp\txzr, xzr," } } */
>> +}
>> +
>> +void
>> +g (float32x2_t *p)
>> +{
>> +  float32x2_t x = {0.0, 0.0};
>> +  p[0] = x;
>> +
>> +  /* { dg-final { scan-assembler "str\txzr, " } } */
>> +}
>>


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diff --git a/gcc/config/aarch64/aarch64-simd.md b/gcc/config/aarch64/aarch64-simd.md
index 74de9b8c89dd5e4e3d87504594c969de0e0128ce..ce1b981fc005edf48a401a456def2a37cf9d9022 100644
--- a/gcc/config/aarch64/aarch64-simd.md
+++ b/gcc/config/aarch64/aarch64-simd.md
@@ -23,7 +23,10 @@
 	(match_operand:VALL_F16 1 "general_operand" ""))]
   "TARGET_SIMD"
   "
-    if (GET_CODE (operands[0]) == MEM)
+    if (GET_CODE (operands[0]) == MEM
+	&& !(aarch64_simd_imm_zero (operands[1], <MODE>mode)
+	     && aarch64_legitimate_address_p (<MODE>mode, operands[0],
+					      PARALLEL, 1)))
       operands[1] = force_reg (<MODE>mode, operands[1]);
   "
 )
@@ -94,63 +97,66 @@
 
 (define_insn "*aarch64_simd_mov<mode>"
   [(set (match_operand:VD 0 "nonimmediate_operand"
-		"=w, m,  w, ?r, ?w, ?r, w")
+		"=w, m,  m,  w, ?r, ?w, ?r, w")
 	(match_operand:VD 1 "general_operand"
-		"m,  w,  w,  w,  r,  r, Dn"))]
+		"m,  Dz, w,  w,  w,  r,  r, Dn"))]
   "TARGET_SIMD
    && (register_operand (operands[0], <MODE>mode)
-       || register_operand (operands[1], <MODE>mode))"
+       || aarch64_simd_reg_or_zero (operands[1], <MODE>mode))"
 {
    switch (which_alternative)
      {
-     case 0: return "ldr\\t%d0, %1";
-     case 1: return "str\\t%d1, %0";
-     case 2: return "mov\t%0.<Vbtype>, %1.<Vbtype>";
-     case 3: return "umov\t%0, %1.d[0]";
-     case 4: return "fmov\t%d0, %1";
-     case 5: return "mov\t%0, %1";
-     case 6:
+     case 0: return "ldr\t%d0, %1";
+     case 1: return "str\txzr, %0";
+     case 2: return "str\t%d1, %0";
+     case 3: return "mov\t%0.<Vbtype>, %1.<Vbtype>";
+     case 4: return "umov\t%0, %1.d[0]";
+     case 5: return "fmov\t%d0, %1";
+     case 6: return "mov\t%0, %1";
+     case 7:
 	return aarch64_output_simd_mov_immediate (operands[1],
 						  <MODE>mode, 64);
      default: gcc_unreachable ();
      }
 }
-  [(set_attr "type" "neon_load1_1reg<q>, neon_store1_1reg<q>,\
+  [(set_attr "type" "neon_load1_1reg<q>, neon_stp, neon_store1_1reg<q>,\
 		     neon_logic<q>, neon_to_gp<q>, f_mcr,\
 		     mov_reg, neon_move<q>")]
 )
 
 (define_insn "*aarch64_simd_mov<mode>"
   [(set (match_operand:VQ 0 "nonimmediate_operand"
-		"=w, m,  w, ?r, ?w, ?r, w")
+		"=w, Ump,  m,  w, ?r, ?w, ?r, w")
 	(match_operand:VQ 1 "general_operand"
-		"m,  w,  w,  w,  r,  r, Dn"))]
+		"m,  Dz, w,  w,  w,  r,  r, Dn"))]
   "TARGET_SIMD
    && (register_operand (operands[0], <MODE>mode)
-       || register_operand (operands[1], <MODE>mode))"
+       || aarch64_simd_reg_or_zero (operands[1], <MODE>mode))"
 {
   switch (which_alternative)
     {
     case 0:
-	return "ldr\\t%q0, %1";
+	return "ldr\t%q0, %1";
     case 1:
-	return "str\\t%q1, %0";
+	return "stp\txzr, xzr, %0";
     case 2:
-	return "mov\t%0.<Vbtype>, %1.<Vbtype>";
+	return "str\t%q1, %0";
     case 3:
+	return "mov\t%0.<Vbtype>, %1.<Vbtype>";
     case 4:
     case 5:
-	return "#";
     case 6:
+	return "#";
+    case 7:
 	return aarch64_output_simd_mov_immediate (operands[1], <MODE>mode, 128);
     default:
 	gcc_unreachable ();
     }
 }
   [(set_attr "type" "neon_load1_1reg<q>, neon_store1_1reg<q>,\
-                     neon_logic<q>, multiple, multiple, multiple,\
-                     neon_move<q>")
-   (set_attr "length" "4,4,4,8,8,8,4")]
+		     neon_stp, neon_logic<q>, multiple, multiple,\
+		     multiple, neon_move<q>")
+   (set_attr "length" "4,4,4,4,8,8,8,4")]
 )
 
 ;; When storing lane zero we can use the normal STR and its more permissive
diff --git a/gcc/testsuite/gcc.target/aarch64/simd/neon_str_zero.c b/gcc/testsuite/gcc.target/aarch64/simd/neon_str_zero.c
new file mode 100644
index 0000000000000000000000000000000000000000..07198de109432b530745cc540790303ae0245efb
--- /dev/null
+++ b/gcc/testsuite/gcc.target/aarch64/simd/neon_str_zero.c
@@ -0,0 +1,22 @@
+/* { dg-do compile } */
+/* { dg-options "-O1" } */
+
+#include <arm_neon.h>
+
+void
+f (uint32x4_t *p)
+{
+  uint32x4_t x = { 0, 0, 0, 0};
+  p[1] = x;
+
+  /* { dg-final { scan-assembler "stp\txzr, xzr," } } */
+}
+
+void
+g (float32x2_t *p)
+{
+  float32x2_t x = {0.0, 0.0};
+  p[0] = x;
+
+  /* { dg-final { scan-assembler "str\txzr, " } } */
+}

  reply	other threads:[~2017-08-16 15:19 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-08-10 13:38 Jackson Woodruff
2017-08-11 15:16 ` Richard Earnshaw (lists)
2017-08-16 16:01   ` Jackson Woodruff [this message]
2017-08-17 13:56     ` Richard Earnshaw (lists)
2017-08-23 14:46     ` Richard Sandiford
2017-08-23 15:06 Wilco Dijkstra
2017-09-06  9:03 ` Jackson Woodruff
2017-09-12 16:28   ` James Greenhalgh
2017-09-13 16:35     ` Jackson Woodruff
2017-09-13 16:51       ` James Greenhalgh

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