[PATCH 1/2] Power10: Add IEEE 128-bit xsmaxcqp and xsmincqp support.

[Michael Meissner <meissner@linux.ibm.com>]

Power10: Add IEEE 128-bit xsmaxcqp and xsmincqp support.

This patch adds the support for the IEEE 128-bit floating point C minimum and
maximum instructions.  The next patch will add the support for using the
compare and set mask instruction to implement conditional moves.

Originally, I tried to add the min/max instructions via a super defination that
covers all of the types.  In this patch, based on patch feedback, I rewrote the
patch to be simpler and just provide the new instructions as a separate insn.

I have built little endian power9 bootstrap compilers with these patches in it,
and there were no regressions.  I have also build big endian power8 bootstrap
compilers, and there were no regressions.  Can I check this into the master
branch?

gcc/
2020-11-15  Michael Meissner  <meissner@linux.ibm.com>

	* config/rs6000/rs6000.c (rs6000_emit_minmax): Add support for ISA
	3.1 IEEE 128-bit floating point xsmaxcqp and xsmincqp instructions.
	* config/rs6000/rs60000.h (FLOAT128_MIN_MAX_FPMASK_P): New macro.
	* config/rs6000/rs6000.md (s<minmax><mode>3): Add support for the
	ISA 3.1 IEEE 128-bit minimum and maximum instructions.

gcc/testsuite/
2020-11-15  Michael Meissner  <meissner@linux.ibm.com>

	* gcc.target/powerpc/float128-minmax-2.c: New test.
---
 gcc/config/rs6000/rs6000.c                        |  3 ++-
 gcc/config/rs6000/rs6000.h                        |  5 +++++
 gcc/config/rs6000/rs6000.md                       | 11 +++++++++++
 .../gcc.target/powerpc/float128-minmax-2.c        | 15 +++++++++++++++
 4 files changed, 33 insertions(+), 1 deletion(-)
 create mode 100644 gcc/testsuite/gcc.target/powerpc/float128-minmax-2.c

diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c
index d7dcd93f088..f6a1f63e842 100644
--- a/gcc/config/rs6000/rs6000.c
+++ b/gcc/config/rs6000/rs6000.c
@@ -15741,7 +15741,8 @@ rs6000_emit_minmax (rtx dest, enum rtx_code code, rtx op0, rtx op1)
   /* VSX/altivec have direct min/max insns.  */
   if ((code == SMAX || code == SMIN)
       && (VECTOR_UNIT_ALTIVEC_OR_VSX_P (mode)
-	  || (mode == SFmode && VECTOR_UNIT_VSX_P (DFmode))))
+	  || (mode == SFmode && VECTOR_UNIT_VSX_P (DFmode))
+	  || FLOAT128_MIN_MAX_FPMASK_P (mode)))
     {
       emit_insn (gen_rtx_SET (dest, gen_rtx_fmt_ee (code, mode, op0, op1)));
       return;
diff --git a/gcc/config/rs6000/rs6000.h b/gcc/config/rs6000/rs6000.h
index 5a47aa14722..886559dbfdf 100644
--- a/gcc/config/rs6000/rs6000.h
+++ b/gcc/config/rs6000/rs6000.h
@@ -345,6 +345,11 @@ extern const char *host_detect_local_cpu (int argc, const char **argv);
    || ((MODE) == TDmode)						\
    || (!TARGET_FLOAT128_TYPE && FLOAT128_IEEE_P (MODE)))
 
+/* Macro whether the float128 minimum, maximum, and set compare mask
+   instructions are enabled.  */
+#define FLOAT128_MIN_MAX_FPMASK_P(MODE)					\
+  (TARGET_POWER10 && TARGET_FLOAT128_HW && FLOAT128_IEEE_P (MODE))
+
 /* Return true for floating point that does not use a vector register.  */
 #define SCALAR_FLOAT_MODE_NOT_VECTOR_P(MODE)				\
   (SCALAR_FLOAT_MODE_P (MODE) && !FLOAT128_VECTOR_P (MODE))
diff --git a/gcc/config/rs6000/rs6000.md b/gcc/config/rs6000/rs6000.md
index 5e5ad9f7c3d..d8fbac124fb 100644
--- a/gcc/config/rs6000/rs6000.md
+++ b/gcc/config/rs6000/rs6000.md
@@ -5163,6 +5163,17 @@ (define_insn "*s<minmax><mode>3_vsx"
 }
   [(set_attr "type" "fp")])
 
+;; Min/max for ISA 3.1 IEEE 128-bit floating point
+(define_insn "s<minmax><mode>3"
+  [(set (match_operand:IEEE128 0 "altivec_register_operand" "=v")
+	(fp_minmax:IEEE128
+	 (match_operand:IEEE128 1 "altivec_register_operand" "v")
+	 (match_operand:IEEE128 2 "altivec_register_operand" "v")))]
+  "TARGET_POWER10"
+  "xs<minmax>cqp %0,%1,%2"
+  [(set_attr "type" "vecfloat")
+   (set_attr "size" "128")])
+
 ;; The conditional move instructions allow us to perform max and min operations
 ;; even when we don't have the appropriate max/min instruction using the FSEL
 ;; instruction.
diff --git a/gcc/testsuite/gcc.target/powerpc/float128-minmax-2.c b/gcc/testsuite/gcc.target/powerpc/float128-minmax-2.c
new file mode 100644
index 00000000000..c71ba08c9f8
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/float128-minmax-2.c
@@ -0,0 +1,15 @@
+/* { dg-require-effective-target ppc_float128_hw } */
+/* { dg-require-effective-target power10_ok } */
+/* { dg-options "-mdejagnu-cpu=power10 -O2 -ffast-math" } */
+
+#ifndef TYPE
+#define TYPE _Float128
+#endif
+
+/* Test that the fminf128/fmaxf128 functions generate if/then/else and not a
+   call.  */
+TYPE f128_min (TYPE a, TYPE b) { return __builtin_fminf128 (a, b); }
+TYPE f128_max (TYPE a, TYPE b) { return __builtin_fmaxf128 (a, b); }
+
+/* { dg-final { scan-assembler {\mxsmaxcqp\M} } } */
+/* { dg-final { scan-assembler {\mxsmincqp\M} } } */
-- 
2.22.0


-- 
Michael Meissner, IBM
IBM, M/S 2506R, 550 King Street, Littleton, MA 01460-6245, USA
email: meissner@linux.ibm.com, phone: +1 (978) 899-4797