rs6000: Generate _Decimal128 to _Decimal32 hardware conversion instructions

We do not currently generate hardware conversion instructions when
converting from _Decimal128 to _Decimal32.  There is no one instruction
that does the conversion, so we currently call the __dpd_trunctdsd2
lib function to do the conversion for us.  However, there is a short
sequence of dfp hardware instructions that will do the conversion
correctly.

2020-07-17  Peter Bergner  <bergner@linux.ibm.com>

gcc/
	PR target/92488
	* config/rs6000/dfp.md (trunctdsd2): New define_insn.
	* config/rs6000/rs6000.md (define_attr "isa"): Add p9.
	(define_attr "enabled"): Handle p9.

gcc/testsuite/
	PR target/92488
	* gcc.target/powerpc/convert-fp-128.c (bl, drsp, drdpq): Update counts.
	(__dpd_trunctdsd2): Make conditional on !hard_dfp.
	(__dpd_extendsddd2, __dpd_extendsdtd2, __dpd_truncddsd2,
	__dpd_extendddtd2, __dpd_trunctddd2): Use !hard_dfp.
	* gcc.target/powerpc/pr92488.c: New test.
This commit is contained in:
Peter Bergner 2020-07-17 21:06:30 -05:00
parent ab660b01c3
commit 8a8c257356
4 changed files with 70 additions and 10 deletions

View File

@ -155,6 +155,19 @@
[(set_attr "type" "dfp")
(set_attr "length" "8")])
(define_insn "trunctdsd2"
[(set (match_operand:SD 0 "gpc_reg_operand" "=d,d")
(float_truncate:SD (match_operand:TD 1 "gpc_reg_operand" "d,d")))
(clobber (match_scratch:TD 2 "=&d,&d"))
(clobber (match_scratch:DF 3 "=&d,&d"))]
"TARGET_DFP"
"@
mffscdrni %3,7\;drdpq %2,%1\;mffscdrn %3,%3\;drsp %0,%2
mffs %3\;mtfsfi 7,7,1\;drdpq %2,%1\;mtfsf 0xff,%3,1,0\;drsp %0,%2"
[(set_attr "type" "dfp")
(set_attr "isa" "p9,*")
(set_attr "length" "16,20")])
(define_insn "add<mode>3"
[(set (match_operand:DDTD 0 "gpc_reg_operand" "=d")
(plus:DDTD (match_operand:DDTD 1 "gpc_reg_operand" "%d")

View File

@ -322,7 +322,7 @@
(const (symbol_ref "(enum attr_cpu) rs6000_tune")))
;; The ISA we implement.
(define_attr "isa" "any,p5,p6,p7,p7v,p8v,p9v,p9kf,p9tf,p10"
(define_attr "isa" "any,p5,p6,p7,p7v,p8v,p9,p9v,p9kf,p9tf,p10"
(const_string "any"))
;; Is this alternative enabled for the current CPU/ISA/etc.?
@ -351,6 +351,10 @@
(match_test "TARGET_P8_VECTOR"))
(const_int 1)
(and (eq_attr "isa" "p9")
(match_test "TARGET_MODULO"))
(const_int 1)
(and (eq_attr "isa" "p9v")
(match_test "TARGET_P9_VECTOR"))
(const_int 1)

View File

@ -34,7 +34,7 @@ conv2
/* { dg-final { scan-assembler-times {\mbl\M} 24 { target { ! hard_dfp } } } } */
/* { dg-final { scan-assembler-times {\mbl\M} 19 { target { hard_dfp && { ! ppc_float128 } } } } } */
/* { dg-final { scan-assembler-times {\mbl\M} 31 { target { hard_dfp && { ppc_float128 && { ! ppc_float128_insns } } } } } } */
/* { dg-final { scan-assembler-times {\mbl\M} 30 { target { hard_dfp && { ppc_float128 && { ! ppc_float128_insns } } } } } } */
/* { dg-final { scan-assembler-times {\mbl\M} 27 { target { hard_dfp && { ppc_float128 && { ppc_float128_insns } } } } } } */
@ -60,20 +60,20 @@ conv2
/* { dg-final { scan-assembler-times {\mbl __dpd_extendsddf\M} 1 } } */
/* { dg-final { scan-assembler-times {\mbl __dpd_extendsdtf\M} 1 } } */
/* { dg-final { scan-assembler-times {\mbl __dpd_extendsdkf\M} 1 { target { ppc_float128 } } } } */
/* { dg-final { scan-assembler-times {\mbl __dpd_extendsddd2\M} 1 { target { ! dfp } } } } */
/* { dg-final { scan-assembler-times {\mbl __dpd_extendsdtd2\M} 1 { target { ! dfp } } } } */
/* { dg-final { scan-assembler-times {\mbl __dpd_extendsddd2\M} 1 { target { ! hard_dfp } } } } */
/* { dg-final { scan-assembler-times {\mbl __dpd_extendsdtd2\M} 1 { target { ! hard_dfp } } } } */
/* { dg-final { scan-assembler-times {\mbl __dpd_truncddsf\M} 1 } } */
/* { dg-final { scan-assembler-times {\mbl __dpd_truncdddf\M} 1 } } */
/* { dg-final { scan-assembler-times {\mbl __dpd_extendddtf\M} 1 } } */
/* { dg-final { scan-assembler-times {\mbl __dpd_extendddkf\M} 1 { target { ppc_float128 } } } } */
/* { dg-final { scan-assembler-times {\mbl __dpd_truncddsd2\M} 1 { target { ! dfp } } } } */
/* { dg-final { scan-assembler-times {\mbl __dpd_extendddtd2\M} 1 { target { ! dfp } } } } */
/* { dg-final { scan-assembler-times {\mbl __dpd_truncddsd2\M} 1 { target { ! hard_dfp } } } } */
/* { dg-final { scan-assembler-times {\mbl __dpd_extendddtd2\M} 1 { target { ! hard_dfp } } } } */
/* { dg-final { scan-assembler-times {\mbl __dpd_trunctdsf\M} 1 } } */
/* { dg-final { scan-assembler-times {\mbl __dpd_trunctddf\M} 1 } } */
/* { dg-final { scan-assembler-times {\mbl __dpd_trunctdtf\M} 1 } } */
/* { dg-final { scan-assembler-times {\mbl __dpd_trunctdkf\M} 1 { target { ppc_float128 } } } } */
/* { dg-final { scan-assembler-times {\mbl __dpd_trunctdsd2\M} 1 } } */
/* { dg-final { scan-assembler-times {\mbl __dpd_trunctddd2\M} 1 { target { ! dfp } } } } */
/* { dg-final { scan-assembler-times {\mbl __dpd_trunctdsd2\M} 1 { target { ! hard_dfp } } } } */
/* { dg-final { scan-assembler-times {\mbl __dpd_trunctddd2\M} 1 { target { ! hard_dfp } } } } */
/* { dg-final { scan-assembler-times {\mfrsp|xsrsp\M} 2 { target { ! ppc_float128_insns } } } } */
@ -88,8 +88,8 @@ conv2
/* { dg-final { scan-assembler-times {\mxxlor|xscpsgndp\M} 3 { target { ppc_float128_insns } } } } */
/* { dg-final { scan-assembler-times {\mdrsp\M} 1 { target { hard_dfp } } } } */
/* { dg-final { scan-assembler-times {\mdrdpq\M} 1 { target { hard_dfp } } } } */
/* { dg-final { scan-assembler-times {\mdrsp\M} 2 { target { hard_dfp } } } } */
/* { dg-final { scan-assembler-times {\mdrdpq\M} 2 { target { hard_dfp } } } } */
/* { dg-final { scan-assembler-times {\mdctdp\M} 2 { target { hard_dfp } } } } */
/* { dg-final { scan-assembler-times {\mdctqpq\M} 2 { target { hard_dfp } } } } */

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@ -0,0 +1,43 @@
/* { dg-do run } */
/* { dg-require-effective-target dfprt } */
/* { dg-options "-O2" } */
#include <stdio.h>
#include <stdlib.h>
/* Runnable test case for testing _Decimal128 to _Decimal32 rounding.
The value below when rounded to _Decimal64 would result in the value
1.2345675e+00, which if it were rounded to _Decimal32 would result in
the value 1.234568e+00. However, the correct value when rounding from
_Decimal128 directly to _Decimal32 is 1.234567e+00. */
_Decimal128 td = 1.23456749999999999999e+00dl;
_Decimal32 sd_expected = 1.234567e+00df;
_Decimal32 __attribute__((noinline))
td2sd (_Decimal128 td)
{
return td;
}
int
main (void)
{
_Decimal32 sd = td2sd (td);
if (sd != sd_expected)
{
union {
_Decimal32 sd;
unsigned int i;
} u;
printf ("cast to _Decimal32 failed:\n");
u.sd = sd;
printf (" actual = 0x%x\n", u.i);
u.sd = sd_expected;
printf (" expected = 0x%x\n", u.i);
abort ();
}
return 0;
}