Allow __ibm128 even if IEEE 128-bit floating point is not supported.
This patch allows the use of the __ibm128 keyword on non-VSX systems.
Originally, the __ibm128 keyword was only enabled when the IEEE 128-bit
floating point is enabled. Sometime back in the GCC 12 development period,
Segher asked that the __ibm128 keyword be allowed in older systems that don't
support IEEE 128-bit. But at the time, stage 1 had closed for GCC 12, so I
deferred doing this change until GCC 13. This patch allows __ibm128 to be used
if either IEEE 128-bit is enabled or long double used the IBM 128-bit format.
I have tested these patches on the following systems:
1) LE Power10 using --with-cpu=power10 --with-long-double-format=ieee
2) LE Power10 using --with-cpu=power9 --with-long-double-format=ibm
3) LE Power10 using --with-cpu=power8 --with-long-double-format=ibm
4) LE Power10 using --with-cpu=power10 --with-long-double-format=ibm
5) LE Power9 using --with-cpu=power9 --with-long-double-format=ibm
6) BE Power8 using --with-cpu=power8 --with-long-double-format=ibm
7) BE Power8 using --with-cpu=power5 --with-long-double-format=ibm
There were no regressions in the build or in the tests.
Can I check this patch into the trunk?
Did we want to backport this to earlier GCC releases?
2022-08-17 Michael Meissner <meiss...@linux.ibm.com>
gcc/
* config/rs6000/rs6000-builtins.cc (rs6000_init_builtins): Enable using
the__ibm128 keyword on systems that either use the 128-bit IBM long
double format for long double or support IEEE 128-bit.
* config/rs6000/rs6000.cc (rs6000_init_libfuncs): Create IBM 128-bit
floating point support functions on systems that support the __ibm128
keyword.
(rs6000_scalar_mode_supported_p): Likewise.
* config/rs6000/rs6000.h (TARGET_IBM128): New macro.
* config/rs6000/rs6000.md (@extenddf<mode>2_fprs): Allow IFmode to be
converted even if long double is not 128-bits.
(extenddf<mode>2_vsx): Likewise.
(extendiftf2):Allow conversion on systems that support the __ibm128
keyword.
(extendtfif2): Likewise.
(trunciftf2): Likewise.
(trunctfif2): Likewise.
---
gcc/config/rs6000/rs6000-builtin.cc | 2 +-
gcc/config/rs6000/rs6000.cc | 13 ++++++++-----
gcc/config/rs6000/rs6000.h | 6 ++++++
gcc/config/rs6000/rs6000.md | 13 ++++++-------
4 files changed, 21 insertions(+), 13 deletions(-)
diff --git a/gcc/config/rs6000/rs6000-builtin.cc
b/gcc/config/rs6000/rs6000-builtin.cc
index 12afa86854c..70680890415 100644
--- a/gcc/config/rs6000/rs6000-builtin.cc
+++ b/gcc/config/rs6000/rs6000-builtin.cc
@@ -713,7 +713,7 @@ rs6000_init_builtins (void)
For IEEE 128-bit floating point, always create the type __ieee128. If the
user used -mfloat128, rs6000-c.cc will create a define from __float128 to
__ieee128. */
- if (TARGET_LONG_DOUBLE_128 && (!TARGET_IEEEQUAD || TARGET_FLOAT128_TYPE))
+ if (TARGET_IBM128)
{
if (!TARGET_IEEEQUAD)
ibm128_float_type_node = long_double_type_node;
diff --git a/gcc/config/rs6000/rs6000.cc b/gcc/config/rs6000/rs6000.cc
index df491bee2ea..39527ce9bbc 100644
--- a/gcc/config/rs6000/rs6000.cc
+++ b/gcc/config/rs6000/rs6000.cc
@@ -11115,10 +11115,11 @@ rs6000_init_libfuncs (void)
{
/* __float128 support. */
if (TARGET_FLOAT128_TYPE)
- {
- init_float128_ibm (IFmode);
- init_float128_ieee (KFmode);
- }
+ init_float128_ieee (KFmode);
+
+ /* __ibm128 support. */
+ if (TARGET_IBM128)
+ init_float128_ibm (IFmode);
/* AIX/Darwin/64-bit Linux quad floating point routines. */
if (TARGET_LONG_DOUBLE_128)
@@ -23752,7 +23753,9 @@ rs6000_scalar_mode_supported_p (scalar_mode mode)
if (DECIMAL_FLOAT_MODE_P (mode))
return default_decimal_float_supported_p ();
- else if (TARGET_FLOAT128_TYPE && (mode == KFmode || mode == IFmode))
+ else if (TARGET_FLOAT128_TYPE && mode == KFmode)
+ return true;
+ else if (TARGET_IBM128 && mode == IFmode)
return true;
else
return default_scalar_mode_supported_p (mode);
diff --git a/gcc/config/rs6000/rs6000.h b/gcc/config/rs6000/rs6000.h
index ad9bf0f7358..813ec696c0d 100644
--- a/gcc/config/rs6000/rs6000.h
+++ b/gcc/config/rs6000/rs6000.h
@@ -564,6 +564,12 @@ extern int rs6000_vector_align[];
&& TARGET_P8_VECTOR \
&& TARGET_POWERPC64)
+/* Whether the __ibm128 keyword is allowed. Any system that supports _Float128
+ is assumed to be capable of supporting __ibm128. Similarly if the long
+ double size is 128 bits, we assume __ibm128 is supported. We don't want to
+ support it on a system without existing 128-bit long doubles. */
+#define TARGET_IBM128 (TARGET_FLOAT128_TYPE || TARGET_LONG_DOUBLE_128)
+
/* Inlining allows targets to define the meanings of bits in target_info
field of ipa_fn_summary by itself, the used bits for rs6000 are listed
below. */
diff --git a/gcc/config/rs6000/rs6000.md b/gcc/config/rs6000/rs6000.md
index 1367a2cb779..f942597c3b4 100644
--- a/gcc/config/rs6000/rs6000.md
+++ b/gcc/config/rs6000/rs6000.md
@@ -8586,8 +8586,7 @@ (define_insn_and_split "@extenddf<mode>2_fprs"
(float_extend:IBM128
(match_operand:DF 1 "nonimmediate_operand" "d,m,d")))
(use (match_operand:DF 2 "nonimmediate_operand" "m,m,d"))]
- "!TARGET_VSX && TARGET_HARD_FLOAT
- && TARGET_LONG_DOUBLE_128 && FLOAT128_IBM_P (<MODE>mode)"
+ "!TARGET_VSX && TARGET_HARD_FLOAT && FLOAT128_IBM_P (<MODE>mode)"
"#"
"&& reload_completed"
[(set (match_dup 3) (match_dup 1))
@@ -8604,7 +8603,7 @@ (define_insn_and_split "@extenddf<mode>2_vsx"
[(set (match_operand:IBM128 0 "gpc_reg_operand" "=d,d")
(float_extend:IBM128
(match_operand:DF 1 "nonimmediate_operand" "wa,m")))]
- "TARGET_LONG_DOUBLE_128 && TARGET_VSX && FLOAT128_IBM_P (<MODE>mode)"
+ "TARGET_VSX && FLOAT128_IBM_P (<MODE>mode)"
"#"
"&& reload_completed"
[(set (match_dup 2) (match_dup 1))
@@ -9061,7 +9060,7 @@ (define_insn "*ieee_128bit_vsx_nabs<mode>2_internal"
(define_expand "extendiftf2"
[(set (match_operand:TF 0 "gpc_reg_operand")
(float_extend:TF (match_operand:IF 1 "gpc_reg_operand")))]
- "TARGET_FLOAT128_TYPE"
+ "TARGET_IBM128"
{
rs6000_expand_float128_convert (operands[0], operands[1], false);
DONE;
@@ -9088,7 +9087,7 @@ (define_expand "extendtfkf2"
(define_expand "extendtfif2"
[(set (match_operand:IF 0 "gpc_reg_operand")
(float_extend:IF (match_operand:TF 1 "gpc_reg_operand")))]
- "TARGET_FLOAT128_TYPE"
+ "TARGET_IBM128"
{
rs6000_expand_float128_convert (operands[0], operands[1], false);
DONE;
@@ -9097,7 +9096,7 @@ (define_expand "extendtfif2"
(define_expand "trunciftf2"
[(set (match_operand:TF 0 "gpc_reg_operand")
(float_truncate:TF (match_operand:IF 1 "gpc_reg_operand")))]
- "TARGET_FLOAT128_TYPE"
+ "TARGET_IBM128"
{
rs6000_expand_float128_convert (operands[0], operands[1], false);
DONE;
@@ -9124,7 +9123,7 @@ (define_expand "trunckftf2"
(define_expand "trunctfif2"
[(set (match_operand:IF 0 "gpc_reg_operand")
(float_truncate:IF (match_operand:TF 1 "gpc_reg_operand")))]
- "TARGET_FLOAT128_TYPE"
+ "TARGET_IBM128"
{
rs6000_expand_float128_convert (operands[0], operands[1], false);
DONE;
--
2.37.2
--
Michael Meissner, IBM
PO Box 98, Ayer, Massachusetts, USA, 01432
email: meiss...@linux.ibm.com
