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

[HAO CHEN GUI via Gcc-patches]

David,

  Thanks for your comments. I refined it according to your advice.

ChangeLog

2021-11-01 Haochen Gui <guih...@linux.ibm.com>

gcc/
        * config/rs6000/rs6000-call.c (rs6000_gimple_fold_builtin): Disable
        gimple fold for VSX_BUILTIN_XVMINDP, ALTIVEC_BUILTIN_VMINFP,
        VSX_BUILTIN_XVMAXDP, ALTIVEC_BUILTIN_VMAXFP when fast-math is not
        set.

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


patch.diff

diff --git a/gcc/config/rs6000/rs6000-call.c b/gcc/config/rs6000/rs6000-call.c
index 7d485480225..a8e193a0089 100644
--- a/gcc/config/rs6000/rs6000-call.c
+++ b/gcc/config/rs6000/rs6000-call.c
@@ -12333,6 +12333,14 @@ rs6000_gimple_fold_builtin (gimple_stmt_iterator *gsi)
       return true;
     /* flavors of vec_min.  */
     case VSX_BUILTIN_XVMINDP:
+    case ALTIVEC_BUILTIN_VMINFP:
+      {
+       lhs = gimple_call_lhs (stmt);
+       tree type = TREE_TYPE (lhs);
+       if (HONOR_NANS (type))
+         return false;
+       gcc_fallthrough ();
+      }
     case P8V_BUILTIN_VMINSD:
     case P8V_BUILTIN_VMINUD:
     case ALTIVEC_BUILTIN_VMINSB:
@@ -12341,7 +12349,6 @@ 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);
@@ -12351,6 +12358,14 @@ rs6000_gimple_fold_builtin (gimple_stmt_iterator *gsi)
       return true;
     /* flavors of vec_max.  */
     case VSX_BUILTIN_XVMAXDP:
+    case ALTIVEC_BUILTIN_VMAXFP:
+      {
+       lhs = gimple_call_lhs (stmt);
+       tree type = TREE_TYPE (lhs);
+       if (HONOR_NANS (type))
+         return false;
+       gcc_fallthrough ();
+      }
     case P8V_BUILTIN_VMAXSD:
     case P8V_BUILTIN_VMAXUD:
     case ALTIVEC_BUILTIN_VMAXSB:
@@ -12359,7 +12374,6 @@ 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..3f6e3760075
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/vec-minmax-1.c
@@ -0,0 +1,53 @@
+/* { dg-do compile } */
+/* { 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..b27bebba846
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/vec-minmax-2.c
@@ -0,0 +1,51 @@
+/* { dg-do compile } */
+/* { 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 2/11/2021 下午 9:12, David Edelsohn wrote:
> On Mon, Nov 1, 2021 at 10:40 PM HAO CHEN GUI <guih...@linux.ibm.com> wrote:
>> David,
>>
>>     My patch file was broken. I am sorry for it.  Here is the correct one. 
>> Thanks a lot.
>>
>> ChangeLog
>>
>> 2021-11-01 Haochen Gui <guih...@linux.ibm.com>
>>
>> gcc/
>>         * config/rs6000/rs6000-call.c (rs6000_gimple_fold_builtin): Disable
>>         gimple fold for VSX_BUILTIN_XVMINDP, ALTIVEC_BUILTIN_VMINFP,
>>         VSX_BUILTIN_XVMAXDP, ALTIVEC_BUILTIN_VMAXFP when fast-math is not
>>         set.
>>
>> gcc/testsuite/
>>         * gcc.target/powerpc/vec-minmax-1.c: New test.
>>         * gcc.target/powerpc/vec-minmax-2.c: Likewise.
> This is okay.
>
> The default DejaGNU test action is compile, but it's a good idea to
> include the dg-do line to be clear and document the intention.
>
> Thanks, David
2021-11-01 Haochen Gui <guih...@linux.ibm.com>

gcc/
        * config/rs6000/rs6000-call.c (rs6000_gimple_fold_builtin): Disable
        gimple fold for VSX_BUILTIN_XVMINDP, ALTIVEC_BUILTIN_VMINFP,
        VSX_BUILTIN_XVMAXDP, ALTIVEC_BUILTIN_VMAXFP when fast-math is not
        set.

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 7d485480225..a8e193a0089 100644
--- a/gcc/config/rs6000/rs6000-call.c
+++ b/gcc/config/rs6000/rs6000-call.c
@@ -12333,6 +12333,14 @@ rs6000_gimple_fold_builtin (gimple_stmt_iterator *gsi)
       return true;
     /* flavors of vec_min.  */
     case VSX_BUILTIN_XVMINDP:
+    case ALTIVEC_BUILTIN_VMINFP:
+      {
+       lhs = gimple_call_lhs (stmt);
+       tree type = TREE_TYPE (lhs);
+       if (HONOR_NANS (type))
+         return false;
+       gcc_fallthrough ();
+      }
     case P8V_BUILTIN_VMINSD:
     case P8V_BUILTIN_VMINUD:
     case ALTIVEC_BUILTIN_VMINSB:
@@ -12341,7 +12349,6 @@ 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);
@@ -12351,6 +12358,14 @@ rs6000_gimple_fold_builtin (gimple_stmt_iterator *gsi)
       return true;
     /* flavors of vec_max.  */
     case VSX_BUILTIN_XVMAXDP:
+    case ALTIVEC_BUILTIN_VMAXFP:
+      {
+       lhs = gimple_call_lhs (stmt);
+       tree type = TREE_TYPE (lhs);
+       if (HONOR_NANS (type))
+         return false;
+       gcc_fallthrough ();
+      }
     case P8V_BUILTIN_VMAXSD:
     case P8V_BUILTIN_VMAXUD:
     case ALTIVEC_BUILTIN_VMAXSB:
@@ -12359,7 +12374,6 @@ 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..3f6e3760075
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/vec-minmax-1.c
@@ -0,0 +1,53 @@
+/* { dg-do compile } */
+/* { 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..b27bebba846
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/vec-minmax-2.c
@@ -0,0 +1,51 @@
+/* { dg-do compile } */
+/* { 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);
+}