[PATCH, rs6000] Disable gimple fold for float or double vec_minmax when fast-math is not set

HAO CHEN GUI guihaoc@linux.ibm.com
Thu Aug 26 01:19:30 GMT 2021


Hi Bill,

    Thanks for your comments.

Hi Segher,

    Here is the ChangeLog and patch diff. Thanks.

2021-08-25 Haochen Gui <guihaoc@linux.ibm.com>

gcc/
     * config/rs6000/rs6000-call.c (rs6000_gimple_fold_builtin):
     Modify the VSX_BUILTIN_XVMINDP, ALTIVEC_BUILTIN_VMINFP,
     VSX_BUILTIN_XVMAXDP, ALTIVEC_BUILTIN_VMAXFP expansions.

gcc/testsuite/
     * gcc.target/powerpc/vec-minmax-1.c: New test.
     * gcc.target/powerpc/vec-minmax-2.c: Likewise.

diff --git a/gcc/config/rs6000/rs6000-call.c 
b/gcc/config/rs6000/rs6000-call.c
index b4e13af4dc6..90527734ceb 100644
--- a/gcc/config/rs6000/rs6000-call.c
+++ b/gcc/config/rs6000/rs6000-call.c
@@ -12159,6 +12159,11 @@ rs6000_gimple_fold_builtin 
(gimple_stmt_iterator *gsi)
        return true;
      /* flavors of vec_min.  */
      case VSX_BUILTIN_XVMINDP:
+    case ALTIVEC_BUILTIN_VMINFP:
+      if (!flag_finite_math_only || flag_signed_zeros)
+    return false;
+      /* Fall through to MIN_EXPR.  */
+      gcc_fallthrough ();
      case P8V_BUILTIN_VMINSD:
      case P8V_BUILTIN_VMINUD:
      case ALTIVEC_BUILTIN_VMINSB:
@@ -12167,7 +12172,6 @@ rs6000_gimple_fold_builtin (gimple_stmt_iterator 
*gsi)
      case ALTIVEC_BUILTIN_VMINUB:
      case ALTIVEC_BUILTIN_VMINUH:
      case ALTIVEC_BUILTIN_VMINUW:
-    case ALTIVEC_BUILTIN_VMINFP:
        arg0 = gimple_call_arg (stmt, 0);
        arg1 = gimple_call_arg (stmt, 1);
        lhs = gimple_call_lhs (stmt);
@@ -12177,6 +12181,11 @@ rs6000_gimple_fold_builtin 
(gimple_stmt_iterator *gsi)
        return true;
      /* flavors of vec_max.  */
      case VSX_BUILTIN_XVMAXDP:
+    case ALTIVEC_BUILTIN_VMAXFP:
+      if (!flag_finite_math_only || flag_signed_zeros)
+    return false;
+      /* Fall through to MAX_EXPR.  */
+      gcc_fallthrough ();
      case P8V_BUILTIN_VMAXSD:
      case P8V_BUILTIN_VMAXUD:
      case ALTIVEC_BUILTIN_VMAXSB:
@@ -12185,7 +12194,6 @@ rs6000_gimple_fold_builtin (gimple_stmt_iterator 
*gsi)
      case ALTIVEC_BUILTIN_VMAXUB:
      case ALTIVEC_BUILTIN_VMAXUH:
      case ALTIVEC_BUILTIN_VMAXUW:
-    case ALTIVEC_BUILTIN_VMAXFP:
        arg0 = gimple_call_arg (stmt, 0);
        arg1 = gimple_call_arg (stmt, 1);
        lhs = gimple_call_lhs (stmt);
diff --git a/gcc/testsuite/gcc.target/powerpc/vec-minmax-1.c 
b/gcc/testsuite/gcc.target/powerpc/vec-minmax-1.c
new file mode 100644
index 00000000000..547798fd65c
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/vec-minmax-1.c
@@ -0,0 +1,53 @@
+/* { dg-do compile { target { powerpc*-*-* } } } */
+/* { dg-require-effective-target powerpc_p9vector_ok } */
+/* { dg-options "-O2 -mdejagnu-cpu=power9" } */
+/* { dg-final { scan-assembler-times {\mxvmaxdp\M} 1 } } */
+/* { dg-final { scan-assembler-times {\mxvmaxsp\M} 1 } } */
+/* { dg-final { scan-assembler-times {\mxvmindp\M} 1 } } */
+/* { dg-final { scan-assembler-times {\mxvminsp\M} 1 } } */
+
+/* This test verifies that float or double vec_min/max are bound to
+   xv[min|max][d|s]p instructions when fast-math is not set.  */
+
+
+#include <altivec.h>
+
+#ifdef _BIG_ENDIAN
+   const int PREF_D = 0;
+#else
+   const int PREF_D = 1;
+#endif
+
+double vmaxd (double a, double b)
+{
+  vector double va = vec_promote (a, PREF_D);
+  vector double vb = vec_promote (b, PREF_D);
+  return vec_extract (vec_max (va, vb), PREF_D);
+}
+
+double vmind (double a, double b)
+{
+  vector double va = vec_promote (a, PREF_D);
+  vector double vb = vec_promote (b, PREF_D);
+  return vec_extract (vec_min (va, vb), PREF_D);
+}
+
+#ifdef _BIG_ENDIAN
+   const int PREF_F = 0;
+#else
+   const int PREF_F = 3;
+#endif
+
+float vmaxf (float a, float b)
+{
+  vector float va = vec_promote (a, PREF_F);
+  vector float vb = vec_promote (b, PREF_F);
+  return vec_extract (vec_max (va, vb), PREF_F);
+}
+
+float vminf (float a, float b)
+{
+  vector float va = vec_promote (a, PREF_F);
+  vector float vb = vec_promote (b, PREF_F);
+  return vec_extract (vec_min (va, vb), PREF_F);
+}
diff --git a/gcc/testsuite/gcc.target/powerpc/vec-minmax-2.c 
b/gcc/testsuite/gcc.target/powerpc/vec-minmax-2.c
new file mode 100644
index 00000000000..4c6f4365830
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/vec-minmax-2.c
@@ -0,0 +1,51 @@
+/* { dg-do compile { target { powerpc*-*-* } } } */
+/* { dg-require-effective-target powerpc_p9vector_ok } */
+/* { dg-options "-O2 -mdejagnu-cpu=power9 -ffast-math" } */
+/* { dg-final { scan-assembler-times {\mxsmaxcdp\M} 2 } } */
+/* { dg-final { scan-assembler-times {\mxsmincdp\M} 2 } } */
+
+/* This test verifies that float or double vec_min/max can be converted
+   to scalar comparison when fast-math is set.  */
+
+
+#include <altivec.h>
+
+#ifdef _BIG_ENDIAN
+   const int PREF_D = 0;
+#else
+   const int PREF_D = 1;
+#endif
+
+double vmaxd (double a, double b)
+{
+  vector double va = vec_promote (a, PREF_D);
+  vector double vb = vec_promote (b, PREF_D);
+  return vec_extract (vec_max (va, vb), PREF_D);
+}
+
+double vmind (double a, double b)
+{
+  vector double va = vec_promote (a, PREF_D);
+  vector double vb = vec_promote (b, PREF_D);
+  return vec_extract (vec_min (va, vb), PREF_D);
+}
+
+#ifdef _BIG_ENDIAN
+   const int PREF_F = 0;
+#else
+   const int PREF_F = 3;
+#endif
+
+float vmaxf (float a, float b)
+{
+  vector float va = vec_promote (a, PREF_F);
+  vector float vb = vec_promote (b, PREF_F);
+  return vec_extract (vec_max (va, vb), PREF_F);
+}
+
+float vminf (float a, float b)
+{
+  vector float va = vec_promote (a, PREF_F);
+  vector float vb = vec_promote (b, PREF_F);
+  return vec_extract (vec_min (va, vb), PREF_F);
+}

On 25/8/2021 下午 8:34, Bill Schmidt wrote:
> Hi Haochen,
>
> Thanks for the updates!  This looks good to me; please await Segher's 
> response.
>
> Bill
>
> On 8/25/21 2:06 AM, HAO CHEN GUI wrote:
>> Hi,
>>
>>       I refined the patch according to Bill's advice. I pasted the
>> ChangeLog and diff file here. If it doesn't work, please let me know.
>> Thanks.
>>
>> 2021-08-25 Haochen Gui <guihaoc@linux.ibm.com>
>>
>> gcc/
>>       * config/rs6000/rs6000-call.c (rs6000_gimple_fold_builtin):
>>       Modify the VSX_BUILTIN_XVMINDP, ALTIVEC_BUILTIN_VMINFP,
>>       VSX_BUILTIN_XVMAXDP, ALTIVEC_BUILTIN_VMAXFP expansions.
>>
>> gcc/testsuite/
>>       * gcc.target/powerpc/vec-minmax-1.c: New test.
>>       * gcc.target/powerpc/vec-minmax-2.c: Likewise.
>>
>> diff --git a/gcc/config/rs6000/rs6000-call.c
>> b/gcc/config/rs6000/rs6000-call.c
>> index b4e13af4dc6..90527734ceb 100644
>> --- a/gcc/config/rs6000/rs6000-call.c
>> +++ b/gcc/config/rs6000/rs6000-call.c
>> @@ -12159,6 +12159,11 @@ rs6000_gimple_fold_builtin
>> (gimple_stmt_iterator *gsi)
>>          return true;
>>        /* flavors of vec_min.  */
>>        case VSX_BUILTIN_XVMINDP:
>> +    case ALTIVEC_BUILTIN_VMINFP:
>> +      if (!flag_finite_math_only || flag_signed_zeros)
>> +    return false;
>> +      /* Fall through to MIN_EXPR.  */
>> +      gcc_fallthrough ();
>>        case P8V_BUILTIN_VMINSD:
>>        case P8V_BUILTIN_VMINUD:
>>        case ALTIVEC_BUILTIN_VMINSB:
>> @@ -12167,7 +12172,6 @@ rs6000_gimple_fold_builtin (gimple_stmt_iterator
>> *gsi)
>>        case ALTIVEC_BUILTIN_VMINUB:
>>        case ALTIVEC_BUILTIN_VMINUH:
>>        case ALTIVEC_BUILTIN_VMINUW:
>> -    case ALTIVEC_BUILTIN_VMINFP:
>>          arg0 = gimple_call_arg (stmt, 0);
>>          arg1 = gimple_call_arg (stmt, 1);
>>          lhs = gimple_call_lhs (stmt);
>> @@ -12177,6 +12181,11 @@ rs6000_gimple_fold_builtin
>> (gimple_stmt_iterator *gsi)
>>          return true;
>>        /* flavors of vec_max.  */
>>        case VSX_BUILTIN_XVMAXDP:
>> +    case ALTIVEC_BUILTIN_VMAXFP:
>> +      if (!flag_finite_math_only || flag_signed_zeros)
>> +    return false;
>> +      /* Fall through to MAX_EXPR.  */
>> +      gcc_fallthrough ();
>>        case P8V_BUILTIN_VMAXSD:
>>        case P8V_BUILTIN_VMAXUD:
>>        case ALTIVEC_BUILTIN_VMAXSB:
>> @@ -12185,7 +12194,6 @@ rs6000_gimple_fold_builtin (gimple_stmt_iterator
>> *gsi)
>>        case ALTIVEC_BUILTIN_VMAXUB:
>>        case ALTIVEC_BUILTIN_VMAXUH:
>>        case ALTIVEC_BUILTIN_VMAXUW:
>> -    case ALTIVEC_BUILTIN_VMAXFP:
>>          arg0 = gimple_call_arg (stmt, 0);
>>          arg1 = gimple_call_arg (stmt, 1);
>>          lhs = gimple_call_lhs (stmt);
>> diff --git a/gcc/testsuite/gcc.target/powerpc/vec-minmax-1.c
>> b/gcc/testsuite/gcc.target/powerpc/vec-minmax-1.c
>> new file mode 100644
>> index 00000000000..da92f059aea
>> --- /dev/null
>> +++ b/gcc/testsuite/gcc.target/powerpc/vec-minmax-1.c
>> @@ -0,0 +1,53 @@
>> +/* { dg-do compile { target { powerpc64le-*-* } } } */
>> +/* { dg-require-effective-target powerpc_p9vector_ok } */
>> +/* { dg-options "-O2 -mdejagnu-cpu=power9" } */
>> +/* { dg-final { scan-assembler-times {\mxvmaxdp\M} 1 } } */
>> +/* { dg-final { scan-assembler-times {\mxvmaxsp\M} 1 } } */
>> +/* { dg-final { scan-assembler-times {\mxvmindp\M} 1 } } */
>> +/* { dg-final { scan-assembler-times {\mxvminsp\M} 1 } } */
>> +
>> +/* This test verifies that float or double vec_min/max are bound to
>> +   xv[min|max][d|s]p instructions when fast-math is not set. */
>> +
>> +
>> +#include <altivec.h>
>> +
>> +#ifdef _BIG_ENDIAN
>> +   const int PREF_D = 0;
>> +#else
>> +   const int PREF_D = 1;
>> +#endif
>> +
>> +double vmaxd (double a, double b)
>> +{
>> +  vector double va = vec_promote (a, PREF_D);
>> +  vector double vb = vec_promote (b, PREF_D);
>> +  return vec_extract (vec_max (va, vb), PREF_D);
>> +}
>> +
>> +double vmind (double a, double b)
>> +{
>> +  vector double va = vec_promote (a, PREF_D);
>> +  vector double vb = vec_promote (b, PREF_D);
>> +  return vec_extract (vec_min (va, vb), PREF_D);
>> +}
>> +
>> +#ifdef _BIG_ENDIAN
>> +   const int PREF_F = 0;
>> +#else
>> +   const int PREF_F = 3;
>> +#endif
>> +
>> +float vmaxf (float a, float b)
>> +{
>> +  vector float va = vec_promote (a, PREF_F);
>> +  vector float vb = vec_promote (b, PREF_F);
>> +  return vec_extract (vec_max (va, vb), PREF_F);
>> +}
>> +
>> +float vminf (float a, float b)
>> +{
>> +  vector float va = vec_promote (a, PREF_F);
>> +  vector float vb = vec_promote (b, PREF_F);
>> +  return vec_extract (vec_min (va, vb), PREF_F);
>> +}
>> diff --git a/gcc/testsuite/gcc.target/powerpc/vec-minmax-2.c
>> b/gcc/testsuite/gcc.target/powerpc/vec-minmax-2.c
>> new file mode 100644
>> index 00000000000..d318b933181
>> --- /dev/null
>> +++ b/gcc/testsuite/gcc.target/powerpc/vec-minmax-2.c
>> @@ -0,0 +1,51 @@
>> +/* { dg-do compile { target { powerpc64le-*-* } } } */
>> +/* { dg-require-effective-target powerpc_p9vector_ok } */
>> +/* { dg-options "-O2 -mdejagnu-cpu=power9 -ffast-math" } */
>> +/* { dg-final { scan-assembler-times {\mxsmaxcdp\M} 2 } } */
>> +/* { dg-final { scan-assembler-times {\mxsmincdp\M} 2 } } */
>> +
>> +/* This test verifies that float or double vec_min/max can be converted
>> +   to scalar comparison when fast-math is set.  */
>> +
>> +
>> +#include <altivec.h>
>> +
>> +#ifdef _BIG_ENDIAN
>> +   const int PREF_D = 0;
>> +#else
>> +   const int PREF_D = 1;
>> +#endif
>> +
>> +double vmaxd (double a, double b)
>> +{
>> +  vector double va = vec_promote (a, PREF_D);
>> +  vector double vb = vec_promote (b, PREF_D);
>> +  return vec_extract (vec_max (va, vb), PREF_D);
>> +}
>> +
>> +double vmind (double a, double b)
>> +{
>> +  vector double va = vec_promote (a, PREF_D);
>> +  vector double vb = vec_promote (b, PREF_D);
>> +  return vec_extract (vec_min (va, vb), PREF_D);
>> +}
>> +
>> +#ifdef _BIG_ENDIAN
>> +   const int PREF_F = 0;
>> +#else
>> +   const int PREF_F = 3;
>> +#endif
>> +
>> +float vmaxf (float a, float b)
>> +{
>> +  vector float va = vec_promote (a, PREF_F);
>> +  vector float vb = vec_promote (b, PREF_F);
>> +  return vec_extract (vec_max (va, vb), PREF_F);
>> +}
>> +
>> +float vminf (float a, float b)
>> +{
>> +  vector float va = vec_promote (a, PREF_F);
>> +  vector float vb = vec_promote (b, PREF_F);
>> +  return vec_extract (vec_min (va, vb), PREF_F);
>> +}
>>
>> On 25/8/2021 上午 6:40, Segher Boessenkool wrote:
>>> Hi!
>>>
>>> On Tue, Aug 24, 2021 at 03:04:26PM -0500, Bill Schmidt wrote:
>>>> On 8/24/21 3:52 AM, HAO CHEN GUI wrote:
>>>> Thanks for this patch!  In the future, if you can put your 
>>>> ChangeLog and
>>>> patch inline in your post, it makes it easier to review. (Otherwise we
>>>> have to manually copy it into our response and manipulate it to look
>>>> quoted, etc.)
>>> It is encoded even, making it impossible to easily apply the patch, 
>>> etc.
>>>
>>>>> diff --git a/gcc/config/rs6000/rs6000-call.c
>>>>> b/gcc/config/rs6000/rs6000-call.c index b4e13af4dc6..90527734ceb
>>>>> 100644 --- a/gcc/config/rs6000/rs6000-call.c +++
>>>>> b/gcc/config/rs6000/rs6000-call.c @@ -12159,6 +12159,11 @@
>>>>> rs6000_gimple_fold_builtin (gimple_stmt_iterator *gsi) return 
>>>>> true; /*
>>>>> flavors of vec_min. */ case VSX_BUILTIN_XVMINDP: + case
>>> format=flawed :-(
>>>
>>>
>>> Segher


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