[PATCH 2/2] 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. 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).
This simplification also eliminates having to insert a XXPERMDI instruction if
you are comparing 64-bit values and doing a conditional move with 128-bit
values.
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 '=='.
I have built bootstrap compilers on both a little endian power9 Linux system
and a big endian power8 Linux system. There were no regressions in either
build in the test suites. Can I check these changes into the trunk for gcc 11?
gcc/
2021-04-14 Michael Meissner <meiss...@linux.ibm.com>
* config/rs6000/rs6000.c (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/
2021-04-14 Michael Meissner <meiss...@linux.ibm.com>
* gcc.target/powerpc/float128-cmove.c: New test.
* gcc.target/powerpc/float128-minmax-3.c: New test.
---
gcc/config/rs6000/rs6000.c | 8 +-
gcc/config/rs6000/rs6000.md | 106 ++++++++++++++++++
.../gcc.target/powerpc/float128-cmove.c | 58 ++++++++++
.../gcc.target/powerpc/float128-minmax-3.c | 15 +++
4 files changed, 185 insertions(+), 2 deletions(-)
create mode 100644 gcc/testsuite/gcc.target/powerpc/float128-cmove.c
create mode 100644 gcc/testsuite/gcc.target/powerpc/float128-minmax-3.c
diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c
index 8d00f99e9fd..f979d7320ad 100644
--- a/gcc/config/rs6000/rs6000.c
+++ b/gcc/config/rs6000/rs6000.c
@@ -15706,8 +15706,8 @@ 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
@@ -15843,6 +15843,10 @@ 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 17b2fdc1cdd..c74fc8ce6fc 100644
--- a/gcc/config/rs6000/rs6000.md
+++ b/gcc/config/rs6000/rs6000.md
@@ -5429,6 +5429,112 @@ (define_insn "*xxsel<mode>"
"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 conditional 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 00000000000..2fae8dc23bc
--- /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 00000000000..6f7627c0f2a
--- /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} } } */
--
2.22.0
--
Michael Meissner, IBM
IBM, M/S 2506R, 550 King Street, Littleton, MA 01460-6245, USA
email: meiss...@linux.ibm.com, phone: +1 (978) 899-4797
