Add IEEE 128-bit fp conditional move on PowerPC.

This patch adds the support for power10 IEEE 128-bit floating point conditional
move and for automatically generating min/max.

In this patch, I simplified things compared to previous patches.  Instead of
allowing any four of the modes to be used for the conditional move comparison
and the move itself could use different modes, I restricted the conditional
move to just the same mode.  I.e. you can do:

    _Float128 a, b, c, d, e, r;

    r = (a == b) ? c : d;

But you can't do:

    _Float128 c, d, r;
    double a, b;

    r = (a == b) ? c : d;

or:

    _Float128 a, b;
    double c, d, r;

    r = (a == b) ? c : d;

This eliminates a lot of the complexity of the code, because you don't have to
worry about the sizes being different, and the IEEE 128-bit types being
restricted to Altivec registers, while the SF/DF modes can use any VSX
register.

I did not modify the existing support that allowed conditional moves where
SFmode operands are compared and DFmode operands are moved (and vice versa).

I modified the test cases that I added to reflect this change.  I have also
fixed the test for not equal to use '!=' instead of '=='.

2021-07-01 Michael Meissner  <meissner@linux.ibm.com>

gcc/

	* config/rs6000/rs6000.c (rs6000_maybe_emit_fp_cmove): Add IEEE
	128-bit floating point conditional move support.
	(have_compare_and_set_mask): Add IEEE 128-bit floating point
	types.
	* config/rs6000/rs6000.md (mov<mode>cc, IEEE128 iterator): New insn.
	(mov<mode>cc_p10, IEEE128 iterator): New insn.
	(mov<mode>cc_invert_p10, IEEE128 iterator): New insn.
	(fpmask<mode>, IEEE128 iterator): New insn.
	(xxsel<mode>, IEEE128 iterator): New insn.

gcc/testsuite/

	* gcc.target/powerpc/float128-cmove.c: New test.
	* gcc.target/powerpc/float128-minmax-3.c: New test.

4 files changed, 209 insertions, 2 deletions

diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c
index f3e5f95..9a5db63 100644
--- a/gcc/config/rs6000/rs6000.c
+++ b/gcc/config/rs6000/rs6000.c
@@ -15699,8 +15699,8 @@ rs6000_emit_vector_cond_expr (rtx dest, rtx op_true, rtx op_false,
   return 1;
 }
 
-/* Possibly emit the xsmaxcdp and xsmincdp instructions to emit a maximum or
-   minimum with "C" semantics.
+/* Possibly emit the xsmaxc{dp,qp} and xsminc{dp,qp} instructions to emit a
+   maximum or minimum with "C" semantics.
 
    Unless you use -ffast-math, you can't use these instructions to replace
    conditions that implicitly reverse the condition because the comparison
@@ -15776,6 +15776,7 @@ rs6000_maybe_emit_fp_cmove (rtx dest, rtx op, rtx true_cond, rtx false_cond)
   enum rtx_code code = GET_CODE (op);
   rtx op0 = XEXP (op, 0);
   rtx op1 = XEXP (op, 1);
+  machine_mode compare_mode = GET_MODE (op0);
   machine_mode result_mode = GET_MODE (dest);
   rtx compare_rtx;
   rtx cmove_rtx;
@@ -15784,6 +15785,29 @@ rs6000_maybe_emit_fp_cmove (rtx dest, rtx op, rtx true_cond, rtx false_cond)
   if (!can_create_pseudo_p ())
     return 0;
 
+  /* We allow the comparison to be either SFmode/DFmode and the true/false
+     condition to be either SFmode/DFmode.  I.e. we allow:
+
+	float a, b;
+	double c, d, r;
+
+	r = (a == b) ? c : d;
+
+    and:
+
+	double a, b;
+	float c, d, r;
+
+	r = (a == b) ? c : d;
+
+    but we don't allow intermixing the IEEE 128-bit floating point types with
+    the 32/64-bit scalar types.  */
+
+  if (!(compare_mode == result_mode
+	|| (compare_mode == SFmode && result_mode == DFmode)
+	|| (compare_mode == DFmode && result_mode == SFmode)))
+    return false;
+
   switch (code)
     {
     case EQ:
@@ -15836,6 +15860,10 @@ have_compare_and_set_mask (machine_mode mode)
     case E_DFmode:
       return TARGET_P9_MINMAX;
 
+    case E_KFmode:
+    case E_TFmode:
+      return TARGET_POWER10 && TARGET_FLOAT128_HW && FLOAT128_IEEE_P (mode);
+
     default:
       break;
     }
diff --git a/gcc/config/rs6000/rs6000.md b/gcc/config/rs6000/rs6000.md
index abd825f..e84d031 100644
--- a/gcc/config/rs6000/rs6000.md
+++ b/gcc/config/rs6000/rs6000.md
@@ -5449,6 +5449,112 @@
   "xxsel %x0,%x4,%x3,%x1"
   [(set_attr "type" "vecmove")])
 
+;; Support for ISA 3.1 IEEE 128-bit conditional move.  The mode used in the
+;; comparison must be the same as used in the move.
+(define_expand "mov<mode>cc"
+   [(set (match_operand:IEEE128 0 "gpc_reg_operand")
+	 (if_then_else:IEEE128 (match_operand 1 "comparison_operator")
+			       (match_operand:IEEE128 2 "gpc_reg_operand")
+			       (match_operand:IEEE128 3 "gpc_reg_operand")))]
+  "TARGET_POWER10 && TARGET_FLOAT128_HW && FLOAT128_IEEE_P (<MODE>mode)"
+{
+  if (rs6000_emit_cmove (operands[0], operands[1], operands[2], operands[3]))
+    DONE;
+  else
+    FAIL;
+})
+
+(define_insn_and_split "*mov<mode>cc_p10"
+  [(set (match_operand:IEEE128 0 "altivec_register_operand" "=&v,v")
+	(if_then_else:IEEE128
+	 (match_operator:CCFP 1 "fpmask_comparison_operator"
+		[(match_operand:IEEE128 2 "altivec_register_operand" "v,v")
+		 (match_operand:IEEE128 3 "altivec_register_operand" "v,v")])
+	 (match_operand:IEEE128 4 "altivec_register_operand" "v,v")
+	 (match_operand:IEEE128 5 "altivec_register_operand" "v,v")))
+   (clobber (match_scratch:V2DI 6 "=0,&v"))]
+  "TARGET_POWER10 && TARGET_FLOAT128_HW && FLOAT128_IEEE_P (<MODE>mode)"
+  "#"
+  "&& 1"
+  [(set (match_dup 6)
+	(if_then_else:V2DI (match_dup 1)
+			   (match_dup 7)
+			   (match_dup 8)))
+   (set (match_dup 0)
+	(if_then_else:IEEE128 (ne (match_dup 6)
+				  (match_dup 8))
+			      (match_dup 4)
+			      (match_dup 5)))]
+{
+  if (GET_CODE (operands[6]) == SCRATCH)
+    operands[6] = gen_reg_rtx (V2DImode);
+
+  operands[7] = CONSTM1_RTX (V2DImode);
+  operands[8] = CONST0_RTX (V2DImode);
+}
+ [(set_attr "length" "8")
+  (set_attr "type" "vecperm")])
+
+;; Handle inverting the fpmask comparisons.
+(define_insn_and_split "*mov<mode>cc_invert_p10"
+  [(set (match_operand:IEEE128 0 "altivec_register_operand" "=&v,v")
+	(if_then_else:IEEE128
+	 (match_operator:CCFP 1 "invert_fpmask_comparison_operator"
+		[(match_operand:IEEE128 2 "altivec_register_operand" "v,v")
+		 (match_operand:IEEE128 3 "altivec_register_operand" "v,v")])
+	 (match_operand:IEEE128 4 "altivec_register_operand" "v,v")
+	 (match_operand:IEEE128 5 "altivec_register_operand" "v,v")))
+   (clobber (match_scratch:V2DI 6 "=0,&v"))]
+  "TARGET_POWER10 && TARGET_FLOAT128_HW && FLOAT128_IEEE_P (<MODE>mode)"
+  "#"
+  "&& 1"
+  [(set (match_dup 6)
+	(if_then_else:V2DI (match_dup 9)
+			   (match_dup 7)
+			   (match_dup 8)))
+   (set (match_dup 0)
+	(if_then_else:IEEE128 (ne (match_dup 6)
+				  (match_dup 8))
+			      (match_dup 5)
+			      (match_dup 4)))]
+{
+  rtx op1 = operands[1];
+  enum rtx_code cond = reverse_condition_maybe_unordered (GET_CODE (op1));
+
+  if (GET_CODE (operands[6]) == SCRATCH)
+    operands[6] = gen_reg_rtx (V2DImode);
+
+  operands[7] = CONSTM1_RTX (V2DImode);
+  operands[8] = CONST0_RTX (V2DImode);
+
+  operands[9] = gen_rtx_fmt_ee (cond, CCFPmode, operands[2], operands[3]);
+}
+ [(set_attr "length" "8")
+  (set_attr "type" "vecperm")])
+
+(define_insn "*fpmask<mode>"
+  [(set (match_operand:V2DI 0 "altivec_register_operand" "=v")
+	(if_then_else:V2DI
+	 (match_operator:CCFP 1 "fpmask_comparison_operator"
+		[(match_operand:IEEE128 2 "altivec_register_operand" "v")
+		 (match_operand:IEEE128 3 "altivec_register_operand" "v")])
+	 (match_operand:V2DI 4 "all_ones_constant" "")
+	 (match_operand:V2DI 5 "zero_constant" "")))]
+  "TARGET_POWER10 && TARGET_FLOAT128_HW && FLOAT128_IEEE_P (<MODE>mode)"
+  "xscmp%V1qp %0,%2,%3"
+  [(set_attr "type" "fpcompare")])
+
+(define_insn "*xxsel<mode>"
+  [(set (match_operand:IEEE128 0 "altivec_register_operand" "=v")
+	(if_then_else:IEEE128
+	 (ne (match_operand:V2DI 1 "altivec_register_operand" "v")
+	     (match_operand:V2DI 2 "zero_constant" ""))
+	 (match_operand:IEEE128 3 "altivec_register_operand" "v")
+	 (match_operand:IEEE128 4 "altivec_register_operand" "v")))]
+  "TARGET_POWER10 && TARGET_FLOAT128_HW && FLOAT128_IEEE_P (<MODE>mode)"
+  "xxsel %x0,%x4,%x3,%x1"
+  [(set_attr "type" "vecmove")])
+
 
 ;; Conversions to and from floating-point.
 
diff --git a/gcc/testsuite/gcc.target/powerpc/float128-cmove.c b/gcc/testsuite/gcc.target/powerpc/float128-cmove.c
new file mode 100644
index 0000000..2fae8dc
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/float128-cmove.c
@@ -0,0 +1,58 @@
+/* { dg-do compile } */
+/* { dg-require-effective-target ppc_float128_hw } */
+/* { dg-require-effective-target power10_ok } */
+/* { dg-options "-mdejagnu-cpu=power10 -O2" } */
+
+#ifndef TYPE
+#ifdef __LONG_DOUBLE_IEEE128__
+#define TYPE long double
+
+#else
+#define TYPE _Float128
+#endif
+#endif
+
+/* Verify that the ISA 3.1 (power10) IEEE 128-bit conditional move instructions
+   are generated.  */
+
+TYPE
+eq (TYPE a, TYPE b, TYPE c, TYPE d)
+{
+  return (a == b) ? c : d;
+}
+
+TYPE
+ne (TYPE a, TYPE b, TYPE c, TYPE d)
+{
+  return (a != b) ? c : d;
+}
+
+TYPE
+lt (TYPE a, TYPE b, TYPE c, TYPE d)
+{
+  return (a < b) ? c : d;
+}
+
+TYPE
+le (TYPE a, TYPE b, TYPE c, TYPE d)
+{
+  return (a <= b) ? c : d;
+}
+
+TYPE
+gt (TYPE a, TYPE b, TYPE c, TYPE d)
+{
+  return (a > b) ? c : d;
+}
+
+TYPE
+ge (TYPE a, TYPE b, TYPE c, TYPE d)
+{
+  return (a >= b) ? c : d;
+}
+
+/* { dg-final { scan-assembler-times {\mxscmpeqqp\M} 2 } } */
+/* { dg-final { scan-assembler-times {\mxscmpgeqp\M} 2 } } */
+/* { dg-final { scan-assembler-times {\mxscmpgtqp\M} 2 } } */
+/* { dg-final { scan-assembler-times {\mxxsel\M}     6 } } */
+/* { dg-final { scan-assembler-not   {\mxscmpuqp\M}    } } */
diff --git a/gcc/testsuite/gcc.target/powerpc/float128-minmax-3.c b/gcc/testsuite/gcc.target/powerpc/float128-minmax-3.c
new file mode 100644
index 0000000..6f7627c
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/float128-minmax-3.c
@@ -0,0 +1,15 @@
+/* { dg-require-effective-target ppc_float128_hw } */
+/* { dg-require-effective-target power10_ok } */
+/* { dg-options "-mdejagnu-cpu=power10 -O2" } */
+
+#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 (a < b) ? a : b; }
+TYPE f128_max (TYPE a, TYPE b) { return (b > a) ? b : a; }
+
+/* { dg-final { scan-assembler {\mxsmaxcqp\M} } } */
+/* { dg-final { scan-assembler {\mxsmincqp\M} } } */