[PATCH v4, rs6000] Implemented f[min/max]_optab by xs[min/max]dp [PR103605]

[HAO CHEN GUI via Gcc-patches]

Hi,
  This patch implements optab f[min/max]_optab by xs[min/max]dp on rs6000.
Tests show that outputs of xs[min/max]dp are consistent with the standard
of C99 fmin/max.

  This patch also binds __builtin_vsx_xs[min/max]dp to fmin/max instead
of smin/max. So the builtins always generate xs[min/max]dp on all
platforms.

  Compared with previous version, the main change is to fix indent problem.

  Bootstrapped and tested on ppc64 Linux BE and LE with no regressions.
Is this okay for trunk? Any recommendations? Thanks a lot.

ChangeLog
2022-05-31 Haochen Gui <guih...@linux.ibm.com>

gcc/
        PR target/103605
        * config/rs6000/rs6000.md (FMINMAX): New.
        (minmax_op): New.
        (f<minmax_op><mode>3): New pattern by UNSPEC_FMAX and UNSPEC_FMIN.
        * config/rs6000/rs6000-builtins.def (__builtin_vsx_xsmaxdp): Set
        pattern to fmaxdf3.
        (__builtin_vsx_xsmindp): Set pattern to fmindf3.

gcc/testsuite/
        PR target/103605
        * gcc.dg/powerpc/pr103605.c: New.

patch.diff
diff --git a/gcc/config/rs6000/rs6000-builtins.def 
b/gcc/config/rs6000/rs6000-builtins.def
index f4a9f24bcc5..8b735493b40 100644
--- a/gcc/config/rs6000/rs6000-builtins.def
+++ b/gcc/config/rs6000/rs6000-builtins.def
@@ -1613,10 +1613,10 @@
     XSCVSPDP vsx_xscvspdp {}

   const double __builtin_vsx_xsmaxdp (double, double);
-    XSMAXDP smaxdf3 {}
+    XSMAXDP fmaxdf3 {}

   const double __builtin_vsx_xsmindp (double, double);
-    XSMINDP smindf3 {}
+    XSMINDP fmindf3 {}

   const double __builtin_vsx_xsrdpi (double);
     XSRDPI vsx_xsrdpi {}
diff --git a/gcc/config/rs6000/rs6000.md b/gcc/config/rs6000/rs6000.md
index bf85baa5370..42d3edf2eca 100644
--- a/gcc/config/rs6000/rs6000.md
+++ b/gcc/config/rs6000/rs6000.md
@@ -158,6 +158,8 @@ (define_c_enum "unspec"
    UNSPEC_HASHCHK
    UNSPEC_XXSPLTIDP_CONST
    UNSPEC_XXSPLTIW_CONST
+   UNSPEC_FMAX
+   UNSPEC_FMIN
   ])

 ;;
@@ -5341,6 +5343,22 @@ (define_insn_and_split "*s<minmax><mode>3_fpr"
   DONE;
 })

+
+(define_int_iterator FMINMAX [UNSPEC_FMAX UNSPEC_FMIN])
+
+(define_int_attr  minmax_op [(UNSPEC_FMAX "max")
+                            (UNSPEC_FMIN "min")])
+
+(define_insn "f<minmax_op><mode>3"
+  [(set (match_operand:SFDF 0 "vsx_register_operand" "=wa")
+       (unspec:SFDF [(match_operand:SFDF 1 "vsx_register_operand" "wa")
+                     (match_operand:SFDF 2 "vsx_register_operand" "wa")]
+                    FMINMAX))]
+  "TARGET_VSX"
+  "xs<minmax_op>dp %x0,%x1,%x2"
+  [(set_attr "type" "fp")]
+)
+
 (define_expand "mov<mode>cc"
    [(set (match_operand:GPR 0 "gpc_reg_operand")
         (if_then_else:GPR (match_operand 1 "comparison_operator")
diff --git a/gcc/testsuite/gcc.target/powerpc/pr103605.c 
b/gcc/testsuite/gcc.target/powerpc/pr103605.c
new file mode 100644
index 00000000000..e43ac40c2d1
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/pr103605.c
@@ -0,0 +1,37 @@
+/* { dg-do compile } */
+/* { dg-require-effective-target powerpc_vsx_ok } */
+/* { dg-options "-O1 -mvsx" } */
+/* { dg-final { scan-assembler-times {\mxsmaxdp\M} 3 } } */
+/* { dg-final { scan-assembler-times {\mxsmindp\M} 3 } } */
+
+#include <math.h>
+
+double test1 (double d0, double d1)
+{
+  return fmin (d0, d1);
+}
+
+float test2 (float d0, float d1)
+{
+  return fmin (d0, d1);
+}
+
+double test3 (double d0, double d1)
+{
+  return fmax (d0, d1);
+}
+
+float test4 (float d0, float d1)
+{
+  return fmax (d0, d1);
+}
+
+double test5 (double d0, double d1)
+{
+  return __builtin_vsx_xsmindp (d0, d1);
+}
+
+double test6 (double d0, double d1)
+{
+  return __builtin_vsx_xsmaxdp (d0, d1);
+}