Re: inhibit the sincos optimization when the target has sin and cos instructions

[Cesar Philippidis <cesar@codesourcery.com>]

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On 05/19/2016 04:29 AM, Alexander Monakov wrote:
> On Wed, 18 May 2016, Cesar Philippidis wrote:

> Note that the documentation suggests using 'make_safe_from' to concisely
> express conflict resolution:
> 
>> diff --git a/gcc/config/nvptx/nvptx.md b/gcc/config/nvptx/nvptx.md
>> index 33a4862..69bbb22 100644
>> --- a/gcc/config/nvptx/nvptx.md
>> +++ b/gcc/config/nvptx/nvptx.md
>> @@ -794,6 +794,24 @@
>>    ""
>>    "%.\\tsqrt%#%t0\\t%0, %1;")
>>  
>> +(define_expand "sincossf3"
>> +  [(set (match_operand:SF 0 "nvptx_register_operand" "=R")
>> +	(unspec:SF [(match_operand:SF 2 "nvptx_register_operand" "R")]
>> +	           UNSPEC_COS))
>> +   (set (match_operand:SF 1 "nvptx_register_operand" "=R")
>> +	(unspec:SF [(match_dup 2)] UNSPEC_SIN))]
>> +  "flag_unsafe_math_optimizations"
> 
> ... here instead of special-casing the conflict case in curly braces you can
> just write:
> 
>     "operands[2] = make_safe_from (operands[2], operands[0]);"
> 
>> +{
>> +  if (REGNO (operands[0]) == REGNO (operands[2]))
>> +    {
>> +      rtx tmp = gen_reg_rtx (GET_MODE (operands[2]));
>> +      emit_insn (gen_rtx_SET (tmp, operands[2]));
>> +      emit_insn (gen_sinsf2 (operands[1], tmp));
>> +      emit_insn (gen_cossf2 (operands[0], tmp));
>> +      DONE;
>> +    }
>> +})

Done. Is this ok for trunk?

Cesar


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2016-05-19  Cesar Philippidis  <cesar@codesourcery.com>

	gcc/
	* config/nvptx/nvptx.md (sincossf3): New pattern.

	gcc/testsuite/
	* gcc.target/nvptx/sincos.c: New test.


diff --git a/gcc/config/nvptx/nvptx.md b/gcc/config/nvptx/nvptx.md
index 33a4862..1dd256d 100644
--- a/gcc/config/nvptx/nvptx.md
+++ b/gcc/config/nvptx/nvptx.md
@@ -794,6 +794,16 @@
   ""
   "%.\\tsqrt%#%t0\\t%0, %1;")
 
+(define_expand "sincossf3"
+  [(set (match_operand:SF 0 "nvptx_register_operand" "=R")
+	(unspec:SF [(match_operand:SF 2 "nvptx_register_operand" "R")]
+	           UNSPEC_COS))
+   (set (match_operand:SF 1 "nvptx_register_operand" "=R")
+	(unspec:SF [(match_dup 2)] UNSPEC_SIN))]
+  "flag_unsafe_math_optimizations"
+  "operands[2] = make_safe_from (operands[2], operands[0]);"
+)
+
 (define_insn "sinsf2"
   [(set (match_operand:SF 0 "nvptx_register_operand" "=R")
 	(unspec:SF [(match_operand:SF 1 "nvptx_register_operand" "R")]
diff --git a/gcc/testsuite/gcc.target/nvptx/sincos.c b/gcc/testsuite/gcc.target/nvptx/sincos.c
new file mode 100644
index 0000000..921ec41
--- /dev/null
+++ b/gcc/testsuite/gcc.target/nvptx/sincos.c
@@ -0,0 +1,17 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -ffast-math" } */
+
+extern float sinf (float);
+extern float cosf (float);
+
+float
+sincos_add (float x)
+{
+  float s = sinf (x);
+  float c = cosf (x);
+
+  return s + c;
+}
+
+/* { dg-final { scan-assembler-times "sin.approx.f32" 1 } } */
+/* { dg-final { scan-assembler-times "cos.approx.f32" 1 } } */