[PATCH-1v5,rs6000] Implement optab_isinf for SFDF and IEEE128

Message ID 041c9dd6-4276-41ce-ac77-d214ca571a67@linux.ibm.com
State New
Headers
Series [PATCH-1v5,rs6000] Implement optab_isinf for SFDF and IEEE128 |

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Commit Message

HAO CHEN GUI July 9, 2024, 7:18 a.m. UTC
  Hi,
  This patch implemented optab_isinf for SFDF and IEEE128 by test
data class instructions.

  Compared with previous version, the main changes are:
1 Define 3 mode attributes which are used for predicate, constraint
and asm print selection. They help merge sp/dp/qp patterns to one.
2 Remove original sp/dp and qp patterns and combine them into one.
3 Rename corresponding icode name in rs6000-builtin.cc and
rs6000-builtins.def.
https://gcc.gnu.org/pipermail/gcc-patches/2024-June/655779.html

  The expand "isinf<mode>2" and following insn pattern for TF and
KF mode should be guarded on "TARGET_FLOAT128_HW". It will be
changed in sequential patch as some other "qp" insn patterns are
also need to be changed.

  Bootstrapped and tested on powerpc64-linux BE and LE with no
regressions. Is it OK for trunk?

Thanks
Gui Haochen

ChangeLog
rs6000: Implement optab_isinf for SFDF and IEEE128

gcc/
	PR target/97786
	* config/rs6000/rs6000.md (constant VSX_TEST_DATA_CLASS_NAN,
	VSX_TEST_DATA_CLASS_POS_INF, VSX_TEST_DATA_CLASS_NEG_INF,
	VSX_TEST_DATA_CLASS_POS_ZERO, VSX_TEST_DATA_CLASS_NEG_ZERO,
	VSX_TEST_DATA_CLASS_POS_DENORMAL, VSX_TEST_DATA_CLASS_NEG_DENORMAL):
	Define.
	(mode_attr sdq, vsx_altivec, wa_v, x): Define.
	(mode_iterator IEEE_FP): Define.
	* config/rs6000/vsx.md (isinf<mode>2): New expand.
	(expand xststdcqp_<mode>, xststdc<sd>p): Combine into...
	(expand xststdc_<mode>): ...this.
	(insn *xststdcqp_<mode>, *xststdc<sd>p): Combine into...
	(insn *xststdc_<mode>): ...this.
	* config/rs6000/rs6000-builtin.cc (rs6000_expand_builtin): Rename
	CODE_FOR_xststdcqp_kf as CODE_FOR_xststdc_kf,
	CODE_FOR_xststdcqp_tf as CODE_FOR_xststdc_tf.
	* config/rs6000/rs6000-builtins.def: Rename xststdcdp as xststdc_df,
	xststdcsp as xststdc_sf, xststdcqp_kf as xststdc_kf.

gcc/testsuite/
	PR target/97786
	* gcc.target/powerpc/pr97786-1.c: New test.
	* gcc.target/powerpc/pr97786-2.c: New test.

patch.diff
  

Comments

Kewen.Lin July 10, 2024, 3:04 a.m. UTC | #1
Hi Haochen,

on 2024/7/9 15:18, HAO CHEN GUI wrote:
> Hi,
>   This patch implemented optab_isinf for SFDF and IEEE128 by test
> data class instructions.
> 
>   Compared with previous version, the main changes are:
> 1 Define 3 mode attributes which are used for predicate, constraint
> and asm print selection. They help merge sp/dp/qp patterns to one.
> 2 Remove original sp/dp and qp patterns and combine them into one.
> 3 Rename corresponding icode name in rs6000-builtin.cc and
> rs6000-builtins.def.
> https://gcc.gnu.org/pipermail/gcc-patches/2024-June/655779.html
> 
>   The expand "isinf<mode>2" and following insn pattern for TF and
> KF mode should be guarded on "TARGET_FLOAT128_HW". It will be
> changed in sequential patch as some other "qp" insn patterns are
> also need to be changed.
> 
>   Bootstrapped and tested on powerpc64-linux BE and LE with no
> regressions. Is it OK for trunk?
> 
> Thanks
> Gui Haochen
> 
> ChangeLog
> rs6000: Implement optab_isinf for SFDF and IEEE128
> 
> gcc/
> 	PR target/97786
> 	* config/rs6000/rs6000.md (constant VSX_TEST_DATA_CLASS_NAN,
> 	VSX_TEST_DATA_CLASS_POS_INF, VSX_TEST_DATA_CLASS_NEG_INF,
> 	VSX_TEST_DATA_CLASS_POS_ZERO, VSX_TEST_DATA_CLASS_NEG_ZERO,
> 	VSX_TEST_DATA_CLASS_POS_DENORMAL, VSX_TEST_DATA_CLASS_NEG_DENORMAL):
> 	Define.
> 	(mode_attr sdq, vsx_altivec, wa_v, x): Define.
> 	(mode_iterator IEEE_FP): Define.
> 	* config/rs6000/vsx.md (isinf<mode>2): New expand.
> 	(expand xststdcqp_<mode>, xststdc<sd>p): Combine into...
> 	(expand xststdc_<mode>): ...this.
> 	(insn *xststdcqp_<mode>, *xststdc<sd>p): Combine into...
> 	(insn *xststdc_<mode>): ...this.
> 	* config/rs6000/rs6000-builtin.cc (rs6000_expand_builtin): Rename
> 	CODE_FOR_xststdcqp_kf as CODE_FOR_xststdc_kf,
> 	CODE_FOR_xststdcqp_tf as CODE_FOR_xststdc_tf.
> 	* config/rs6000/rs6000-builtins.def: Rename xststdcdp as xststdc_df,
> 	xststdcsp as xststdc_sf, xststdcqp_kf as xststdc_kf.
> 
> gcc/testsuite/
> 	PR target/97786
> 	* gcc.target/powerpc/pr97786-1.c: New test.
> 	* gcc.target/powerpc/pr97786-2.c: New test.
> 
> patch.diff
> diff --git a/gcc/config/rs6000/rs6000-builtin.cc b/gcc/config/rs6000/rs6000-builtin.cc
> index bb9da68edc7..a62a5d4afa7 100644
> --- a/gcc/config/rs6000/rs6000-builtin.cc
> +++ b/gcc/config/rs6000/rs6000-builtin.cc
> @@ -3357,8 +3357,8 @@ rs6000_expand_builtin (tree exp, rtx target, rtx /* subtarget */,
>        case CODE_FOR_xsiexpqpf_kf:
>  	icode = CODE_FOR_xsiexpqpf_tf;
>  	break;
> -      case CODE_FOR_xststdcqp_kf:
> -	icode = CODE_FOR_xststdcqp_tf;
> +      case CODE_FOR_xststdc_kf:
> +	icode = CODE_FOR_xststdc_tf;
>  	break;
>        case CODE_FOR_xscmpexpqp_eq_kf:
>  	icode = CODE_FOR_xscmpexpqp_eq_tf;
> diff --git a/gcc/config/rs6000/rs6000-builtins.def b/gcc/config/rs6000/rs6000-builtins.def
> index 3bc7fed6956..8ac4cc200c9 100644
> --- a/gcc/config/rs6000/rs6000-builtins.def
> +++ b/gcc/config/rs6000/rs6000-builtins.def
> @@ -2752,11 +2752,11 @@
> 
>    const signed int \
>        __builtin_vsx_scalar_test_data_class_dp (double, const int<7>);
> -    VSTDCDP xststdcdp {}
> +    VSTDCDP xststdc_df {}
> 
>    const signed int \
>        __builtin_vsx_scalar_test_data_class_sp (float, const int<7>);
> -    VSTDCSP xststdcsp {}
> +    VSTDCSP xststdc_sf {}
> 
>    const signed int __builtin_vsx_scalar_test_neg_dp (double);
>      VSTDCNDP xststdcnegdp {}
> @@ -2925,7 +2925,7 @@
> 
>    const signed int __builtin_vsx_scalar_test_data_class_qp (_Float128, \
>                                                              const int<7>);
> -    VSTDCQP xststdcqp_kf {}
> +    VSTDCQP xststdc_kf {}
> 
>    const signed int __builtin_vsx_scalar_test_neg_qp (_Float128);
>      VSTDCNQP xststdcnegqp_kf {}
> diff --git a/gcc/config/rs6000/rs6000.md b/gcc/config/rs6000/rs6000.md
> index a5d20594789..2d7f227e362 100644
> --- a/gcc/config/rs6000/rs6000.md
> +++ b/gcc/config/rs6000/rs6000.md
> @@ -53,6 +53,20 @@ (define_constants
>     (FRAME_POINTER_REGNUM	110)
>    ])
> 
> +;;
> +;; Test data class mask

Nit: s/mask/mask bits/

> +;;
> +
> +(define_constants
> +  [(VSX_TEST_DATA_CLASS_NAN		0x40)
> +   (VSX_TEST_DATA_CLASS_POS_INF		0x20)
> +   (VSX_TEST_DATA_CLASS_NEG_INF		0x10)

Formatting nit: Move 0x20 and 0x10 align with the others?

> +   (VSX_TEST_DATA_CLASS_POS_ZERO	0x8)
> +   (VSX_TEST_DATA_CLASS_NEG_ZERO	0x4)
> +   (VSX_TEST_DATA_CLASS_POS_DENORMAL	0x2)
> +   (VSX_TEST_DATA_CLASS_NEG_DENORMAL	0x1)
> +  ])
> +
>  ;;
>  ;; UNSPEC usage
>  ;;
> @@ -605,6 +619,24 @@ (define_mode_iterator SFDF2 [SF DF])
>  (define_mode_attr sd [(SF   "s") (DF   "d")
>  		      (V4SF "s") (V2DF "d")])
> 
> +; A generic s/d/q attribute, for sp/dp/qp for example.
> +(define_mode_attr sdq [(SF "s") (DF "d")
> +		       (TF "q") (KF "q")])
> +
> +; A predicate attribute, for IEEE floating point
> +(define_mode_attr vsx_altivec [(SF "vsx_register_operand")
> +			       (DF "vsx_register_operand")
> +			       (TF "altivec_register_operand")
> +			       (KF "altivec_register_operand")])

Nit: May be more meaningful with fp_register_op?

> +
> +; A constraint attribute, for IEEE floating point

Nit: Maybe "wa" or "v", for IEEE_FP constraints for example.

> +(define_mode_attr wa_v [(SF "wa") (DF "wa")
> +			(TF "v")  (KF "v")])
> +
> +; A register attribute, for IEEE floating point

Nit: Just follow the existing "s", say: "x" or nothing, for IEEE_FP for example.

> +(define_mode_attr x [(SF "x")  (DF "x")
> +		     (TF  "")  (KF  "")])
> +

Nit: it's would be good to move these three vsx_altivec, wa_v
and x to ...

>  ; "s" or nothing, for fmuls/fmul for example.
>  (define_mode_attr s [(SF "s") (DF "")])
> 
> @@ -616,6 +648,9 @@ (define_mode_iterator IBM128 [(IF "FLOAT128_IBM_P (IFmode)")
>  (define_mode_iterator IEEE128 [(KF "FLOAT128_IEEE_P (KFmode)")
>  			       (TF "FLOAT128_IEEE_P (TFmode)")])
> 
> +; Iterator for IEEE floating point
> +(define_mode_iterator IEEE_FP [SFDF IEEE128])
> +

... here, then they can closely follow the relevant IEEE_FP.

OK with these nits fixed, thanks!

BR,
Kewen

>  ; Iterator for 128-bit floating point
>  (define_mode_iterator FLOAT128 [(KF "TARGET_FLOAT128_TYPE")
>  				(IF "TARGET_FLOAT128_TYPE")
> diff --git a/gcc/config/rs6000/vsx.md b/gcc/config/rs6000/vsx.md
> index 48ba262f7e4..56d1d8c737e 100644
> --- a/gcc/config/rs6000/vsx.md
> +++ b/gcc/config/rs6000/vsx.md
> @@ -5300,36 +5300,15 @@ (define_insn "*xscmpexpqp"
>    "xscmpexpqp %0,%1,%2"
>    [(set_attr "type" "fpcompare")])
> 
> -;; VSX Scalar Test Data Class Quad-Precision
> -;;  (Expansion for scalar_test_data_class (__ieee128, int))
> -;;   (Has side effect of setting the lt bit if operand 1 is negative,
> -;;    setting the eq bit if any of the conditions tested by operand 2
> -;;    are satisfied, and clearing the gt and undordered bits to zero.)
> -(define_expand "xststdcqp_<mode>"
> -  [(set (match_dup 3)
> -	(compare:CCFP
> -	 (unspec:IEEE128
> -	  [(match_operand:IEEE128 1 "altivec_register_operand" "v")
> -	   (match_operand:SI 2 "u7bit_cint_operand" "n")]
> -	  UNSPEC_VSX_STSTDC)
> -	 (const_int 0)))
> -   (set (match_operand:SI 0 "register_operand" "=r")
> -	(eq:SI (match_dup 3)
> -	       (const_int 0)))]
> -  "TARGET_P9_VECTOR"
> -{
> -  operands[3] = gen_reg_rtx (CCFPmode);
> -})
> -
> -;; VSX Scalar Test Data Class Double- and Single-Precision
> +;; VSX Scalar Test Data Class Quad-/Double-/Single-Precision
>  ;;  (The lt bit is set if operand 1 is negative.  The eq bit is set
>  ;;   if any of the conditions tested by operand 2 are satisfied.
>  ;;   The gt and unordered bits are cleared to zero.)
> -(define_expand "xststdc<sd>p"
> +(define_expand "xststdc_<mode>"
>    [(set (match_dup 3)
>  	(compare:CCFP
> -	 (unspec:SFDF
> -	  [(match_operand:SFDF 1 "vsx_register_operand" "wa")
> +	 (unspec:IEEE_FP
> +	  [(match_operand:IEEE_FP 1 "<vsx_altivec>" "<wa_v>")
>  	   (match_operand:SI 2 "u7bit_cint_operand" "n")]
>  	  UNSPEC_VSX_STSTDC)
>  	 (match_dup 4)))
> @@ -5342,6 +5321,16 @@ (define_expand "xststdc<sd>p"
>    operands[4] = CONST0_RTX (SImode);
>  })
> 
> +(define_expand "isinf<mode>2"
> +  [(use (match_operand:SI 0 "gpc_reg_operand"))
> +   (use (match_operand:IEEE_FP 1 "<vsx_altivec>"))]
> +  "TARGET_HARD_FLOAT && TARGET_P9_VECTOR"
> +{
> +  int mask = VSX_TEST_DATA_CLASS_POS_INF | VSX_TEST_DATA_CLASS_NEG_INF;
> +  emit_insn (gen_xststdc_<mode> (operands[0], operands[1], GEN_INT (mask)));
> +  DONE;
> +})
> +
>  ;; The VSX Scalar Test Negative Quad-Precision
>  (define_expand "xststdcnegqp_<mode>"
>    [(set (match_dup 2)
> @@ -5377,27 +5366,16 @@ (define_expand "xststdcneg<sd>p"
>    operands[3] = CONST0_RTX (SImode);
>  })
> 
> -(define_insn "*xststdcqp_<mode>"
> +(define_insn "*xststdc_<mode>"
>    [(set (match_operand:CCFP 0 "" "=y")
>  	(compare:CCFP
> -	 (unspec:IEEE128
> -	  [(match_operand:IEEE128 1 "altivec_register_operand" "v")
> +	 (unspec:IEEE_FP
> +	  [(match_operand:IEEE_FP 1 "<vsx_altivec>" "<wa_v>")
>  	   (match_operand:SI 2 "u7bit_cint_operand" "n")]
>  	  UNSPEC_VSX_STSTDC)
>  	 (const_int 0)))]
>    "TARGET_P9_VECTOR"
> -  "xststdcqp %0,%1,%2"
> -  [(set_attr "type" "fpcompare")])
> -
> -(define_insn "*xststdc<sd>p"
> -  [(set (match_operand:CCFP 0 "" "=y")
> -	(compare:CCFP
> -	 (unspec:SFDF [(match_operand:SFDF 1 "vsx_register_operand" "wa")
> -		       (match_operand:SI 2 "u7bit_cint_operand" "n")]
> -	  UNSPEC_VSX_STSTDC)
> -	 (match_operand:SI 3 "zero_constant" "j")))]
> -  "TARGET_P9_VECTOR"
> -  "xststdc<sd>p %0,%x1,%2"
> +  "xststdc<sdq>p %0,%<x>1,%2"
>    [(set_attr "type" "fpcompare")])
> 
>  ;; VSX Vector Extract Exponent Double and Single Precision
> diff --git a/gcc/testsuite/gcc.target/powerpc/pr97786-1.c b/gcc/testsuite/gcc.target/powerpc/pr97786-1.c
> new file mode 100644
> index 00000000000..3951770f65b
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/powerpc/pr97786-1.c
> @@ -0,0 +1,22 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O2 -mdejagnu-cpu=power9" } */
> +/* { dg-require-effective-target powerpc_vsx } */
> +
> +int test1 (double x)
> +{
> +  return __builtin_isinf (x);
> +}
> +
> +int test2 (float x)
> +{
> +  return __builtin_isinf (x);
> +}
> +
> +int test3 (float x)
> +{
> +  return __builtin_isinff (x);
> +}
> +
> +/* { dg-final { scan-assembler-not {\mfcmp} } } */
> +/* { dg-final { scan-assembler-times {\mxststdcsp\M} 2 } } */
> +/* { dg-final { scan-assembler-times {\mxststdcdp\M} 1 } } */
> diff --git a/gcc/testsuite/gcc.target/powerpc/pr97786-2.c b/gcc/testsuite/gcc.target/powerpc/pr97786-2.c
> new file mode 100644
> index 00000000000..cea2d0dd48e
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/powerpc/pr97786-2.c
> @@ -0,0 +1,17 @@
> +/* { dg-do compile } */
> +/* { dg-require-effective-target ppc_float128_hw } */
> +/* { dg-options "-O2 -mdejagnu-cpu=power9 -mabi=ieeelongdouble -Wno-psabi" } */
> +/* { dg-require-effective-target powerpc_vsx } */
> +
> +int test1 (long double x)
> +{
> +  return __builtin_isinf (x);
> +}
> +
> +int test2 (long double x)
> +{
> +  return __builtin_isinfl (x);
> +}
> +
> +/* { dg-final { scan-assembler-not {\mxscmpuqp\M} } } */
> +/* { dg-final { scan-assembler-times {\mxststdcqp\M} 2 } } */
> 
>
  

Patch

diff --git a/gcc/config/rs6000/rs6000-builtin.cc b/gcc/config/rs6000/rs6000-builtin.cc
index bb9da68edc7..a62a5d4afa7 100644
--- a/gcc/config/rs6000/rs6000-builtin.cc
+++ b/gcc/config/rs6000/rs6000-builtin.cc
@@ -3357,8 +3357,8 @@  rs6000_expand_builtin (tree exp, rtx target, rtx /* subtarget */,
       case CODE_FOR_xsiexpqpf_kf:
 	icode = CODE_FOR_xsiexpqpf_tf;
 	break;
-      case CODE_FOR_xststdcqp_kf:
-	icode = CODE_FOR_xststdcqp_tf;
+      case CODE_FOR_xststdc_kf:
+	icode = CODE_FOR_xststdc_tf;
 	break;
       case CODE_FOR_xscmpexpqp_eq_kf:
 	icode = CODE_FOR_xscmpexpqp_eq_tf;
diff --git a/gcc/config/rs6000/rs6000-builtins.def b/gcc/config/rs6000/rs6000-builtins.def
index 3bc7fed6956..8ac4cc200c9 100644
--- a/gcc/config/rs6000/rs6000-builtins.def
+++ b/gcc/config/rs6000/rs6000-builtins.def
@@ -2752,11 +2752,11 @@ 

   const signed int \
       __builtin_vsx_scalar_test_data_class_dp (double, const int<7>);
-    VSTDCDP xststdcdp {}
+    VSTDCDP xststdc_df {}

   const signed int \
       __builtin_vsx_scalar_test_data_class_sp (float, const int<7>);
-    VSTDCSP xststdcsp {}
+    VSTDCSP xststdc_sf {}

   const signed int __builtin_vsx_scalar_test_neg_dp (double);
     VSTDCNDP xststdcnegdp {}
@@ -2925,7 +2925,7 @@ 

   const signed int __builtin_vsx_scalar_test_data_class_qp (_Float128, \
                                                             const int<7>);
-    VSTDCQP xststdcqp_kf {}
+    VSTDCQP xststdc_kf {}

   const signed int __builtin_vsx_scalar_test_neg_qp (_Float128);
     VSTDCNQP xststdcnegqp_kf {}
diff --git a/gcc/config/rs6000/rs6000.md b/gcc/config/rs6000/rs6000.md
index a5d20594789..2d7f227e362 100644
--- a/gcc/config/rs6000/rs6000.md
+++ b/gcc/config/rs6000/rs6000.md
@@ -53,6 +53,20 @@  (define_constants
    (FRAME_POINTER_REGNUM	110)
   ])

+;;
+;; Test data class mask
+;;
+
+(define_constants
+  [(VSX_TEST_DATA_CLASS_NAN		0x40)
+   (VSX_TEST_DATA_CLASS_POS_INF		0x20)
+   (VSX_TEST_DATA_CLASS_NEG_INF		0x10)
+   (VSX_TEST_DATA_CLASS_POS_ZERO	0x8)
+   (VSX_TEST_DATA_CLASS_NEG_ZERO	0x4)
+   (VSX_TEST_DATA_CLASS_POS_DENORMAL	0x2)
+   (VSX_TEST_DATA_CLASS_NEG_DENORMAL	0x1)
+  ])
+
 ;;
 ;; UNSPEC usage
 ;;
@@ -605,6 +619,24 @@  (define_mode_iterator SFDF2 [SF DF])
 (define_mode_attr sd [(SF   "s") (DF   "d")
 		      (V4SF "s") (V2DF "d")])

+; A generic s/d/q attribute, for sp/dp/qp for example.
+(define_mode_attr sdq [(SF "s") (DF "d")
+		       (TF "q") (KF "q")])
+
+; A predicate attribute, for IEEE floating point
+(define_mode_attr vsx_altivec [(SF "vsx_register_operand")
+			       (DF "vsx_register_operand")
+			       (TF "altivec_register_operand")
+			       (KF "altivec_register_operand")])
+
+; A constraint attribute, for IEEE floating point
+(define_mode_attr wa_v [(SF "wa") (DF "wa")
+			(TF "v")  (KF "v")])
+
+; A register attribute, for IEEE floating point
+(define_mode_attr x [(SF "x")  (DF "x")
+		     (TF  "")  (KF  "")])
+
 ; "s" or nothing, for fmuls/fmul for example.
 (define_mode_attr s [(SF "s") (DF "")])

@@ -616,6 +648,9 @@  (define_mode_iterator IBM128 [(IF "FLOAT128_IBM_P (IFmode)")
 (define_mode_iterator IEEE128 [(KF "FLOAT128_IEEE_P (KFmode)")
 			       (TF "FLOAT128_IEEE_P (TFmode)")])

+; Iterator for IEEE floating point
+(define_mode_iterator IEEE_FP [SFDF IEEE128])
+
 ; Iterator for 128-bit floating point
 (define_mode_iterator FLOAT128 [(KF "TARGET_FLOAT128_TYPE")
 				(IF "TARGET_FLOAT128_TYPE")
diff --git a/gcc/config/rs6000/vsx.md b/gcc/config/rs6000/vsx.md
index 48ba262f7e4..56d1d8c737e 100644
--- a/gcc/config/rs6000/vsx.md
+++ b/gcc/config/rs6000/vsx.md
@@ -5300,36 +5300,15 @@  (define_insn "*xscmpexpqp"
   "xscmpexpqp %0,%1,%2"
   [(set_attr "type" "fpcompare")])

-;; VSX Scalar Test Data Class Quad-Precision
-;;  (Expansion for scalar_test_data_class (__ieee128, int))
-;;   (Has side effect of setting the lt bit if operand 1 is negative,
-;;    setting the eq bit if any of the conditions tested by operand 2
-;;    are satisfied, and clearing the gt and undordered bits to zero.)
-(define_expand "xststdcqp_<mode>"
-  [(set (match_dup 3)
-	(compare:CCFP
-	 (unspec:IEEE128
-	  [(match_operand:IEEE128 1 "altivec_register_operand" "v")
-	   (match_operand:SI 2 "u7bit_cint_operand" "n")]
-	  UNSPEC_VSX_STSTDC)
-	 (const_int 0)))
-   (set (match_operand:SI 0 "register_operand" "=r")
-	(eq:SI (match_dup 3)
-	       (const_int 0)))]
-  "TARGET_P9_VECTOR"
-{
-  operands[3] = gen_reg_rtx (CCFPmode);
-})
-
-;; VSX Scalar Test Data Class Double- and Single-Precision
+;; VSX Scalar Test Data Class Quad-/Double-/Single-Precision
 ;;  (The lt bit is set if operand 1 is negative.  The eq bit is set
 ;;   if any of the conditions tested by operand 2 are satisfied.
 ;;   The gt and unordered bits are cleared to zero.)
-(define_expand "xststdc<sd>p"
+(define_expand "xststdc_<mode>"
   [(set (match_dup 3)
 	(compare:CCFP
-	 (unspec:SFDF
-	  [(match_operand:SFDF 1 "vsx_register_operand" "wa")
+	 (unspec:IEEE_FP
+	  [(match_operand:IEEE_FP 1 "<vsx_altivec>" "<wa_v>")
 	   (match_operand:SI 2 "u7bit_cint_operand" "n")]
 	  UNSPEC_VSX_STSTDC)
 	 (match_dup 4)))
@@ -5342,6 +5321,16 @@  (define_expand "xststdc<sd>p"
   operands[4] = CONST0_RTX (SImode);
 })

+(define_expand "isinf<mode>2"
+  [(use (match_operand:SI 0 "gpc_reg_operand"))
+   (use (match_operand:IEEE_FP 1 "<vsx_altivec>"))]
+  "TARGET_HARD_FLOAT && TARGET_P9_VECTOR"
+{
+  int mask = VSX_TEST_DATA_CLASS_POS_INF | VSX_TEST_DATA_CLASS_NEG_INF;
+  emit_insn (gen_xststdc_<mode> (operands[0], operands[1], GEN_INT (mask)));
+  DONE;
+})
+
 ;; The VSX Scalar Test Negative Quad-Precision
 (define_expand "xststdcnegqp_<mode>"
   [(set (match_dup 2)
@@ -5377,27 +5366,16 @@  (define_expand "xststdcneg<sd>p"
   operands[3] = CONST0_RTX (SImode);
 })

-(define_insn "*xststdcqp_<mode>"
+(define_insn "*xststdc_<mode>"
   [(set (match_operand:CCFP 0 "" "=y")
 	(compare:CCFP
-	 (unspec:IEEE128
-	  [(match_operand:IEEE128 1 "altivec_register_operand" "v")
+	 (unspec:IEEE_FP
+	  [(match_operand:IEEE_FP 1 "<vsx_altivec>" "<wa_v>")
 	   (match_operand:SI 2 "u7bit_cint_operand" "n")]
 	  UNSPEC_VSX_STSTDC)
 	 (const_int 0)))]
   "TARGET_P9_VECTOR"
-  "xststdcqp %0,%1,%2"
-  [(set_attr "type" "fpcompare")])
-
-(define_insn "*xststdc<sd>p"
-  [(set (match_operand:CCFP 0 "" "=y")
-	(compare:CCFP
-	 (unspec:SFDF [(match_operand:SFDF 1 "vsx_register_operand" "wa")
-		       (match_operand:SI 2 "u7bit_cint_operand" "n")]
-	  UNSPEC_VSX_STSTDC)
-	 (match_operand:SI 3 "zero_constant" "j")))]
-  "TARGET_P9_VECTOR"
-  "xststdc<sd>p %0,%x1,%2"
+  "xststdc<sdq>p %0,%<x>1,%2"
   [(set_attr "type" "fpcompare")])

 ;; VSX Vector Extract Exponent Double and Single Precision
diff --git a/gcc/testsuite/gcc.target/powerpc/pr97786-1.c b/gcc/testsuite/gcc.target/powerpc/pr97786-1.c
new file mode 100644
index 00000000000..3951770f65b
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/pr97786-1.c
@@ -0,0 +1,22 @@ 
+/* { dg-do compile } */
+/* { dg-options "-O2 -mdejagnu-cpu=power9" } */
+/* { dg-require-effective-target powerpc_vsx } */
+
+int test1 (double x)
+{
+  return __builtin_isinf (x);
+}
+
+int test2 (float x)
+{
+  return __builtin_isinf (x);
+}
+
+int test3 (float x)
+{
+  return __builtin_isinff (x);
+}
+
+/* { dg-final { scan-assembler-not {\mfcmp} } } */
+/* { dg-final { scan-assembler-times {\mxststdcsp\M} 2 } } */
+/* { dg-final { scan-assembler-times {\mxststdcdp\M} 1 } } */
diff --git a/gcc/testsuite/gcc.target/powerpc/pr97786-2.c b/gcc/testsuite/gcc.target/powerpc/pr97786-2.c
new file mode 100644
index 00000000000..cea2d0dd48e
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/pr97786-2.c
@@ -0,0 +1,17 @@ 
+/* { dg-do compile } */
+/* { dg-require-effective-target ppc_float128_hw } */
+/* { dg-options "-O2 -mdejagnu-cpu=power9 -mabi=ieeelongdouble -Wno-psabi" } */
+/* { dg-require-effective-target powerpc_vsx } */
+
+int test1 (long double x)
+{
+  return __builtin_isinf (x);
+}
+
+int test2 (long double x)
+{
+  return __builtin_isinfl (x);
+}
+
+/* { dg-final { scan-assembler-not {\mxscmpuqp\M} } } */
+/* { dg-final { scan-assembler-times {\mxststdcqp\M} 2 } } */