diff mbox series

[v3] rs6000: Guard bifs {un, }pack_{longdouble, ibm128} under hard float [PR103623]

Message ID 900ac453-f5e8-c2cb-8245-0f8b59300e48@linux.ibm.com
State New
Headers
Series [v3] rs6000: Guard bifs {un, }pack_{longdouble, ibm128} under hard float [PR103623] |

Commit Message

Kewen.Lin April 11, 2022, 8:27 a.m. UTC 
  Hi,

As PR103623 shows, it's a regression failure due to new built-in
function framework, previously we guard __builtin_{un,}pack_{longdouble,
ibm128} built-in functions under hard float, so they are unavailable
with the given configuration.  While with new bif infrastructure, it
becomes available and gets ICE due to incomplete supports.

Segher and Peter pointed out that we should make it available with
soft float, I agree we can extend it to cover both soft and hard
float.  But considering it's stage 4 now and this regression is
classified as P1, also the previous behavior requiring hard float
aligns with what document [1] says, I think it may be a good idea to
fix it with a small patch to be consistent with the previous
behavior.  Then we can extend the functionality by being tracked in new
PR105213 for GCC13.

Re-bootstrapped and re-tested as before.

v1: https://gcc.gnu.org/pipermail/gcc-patches/2022-March/591147.html

v2: Add one more test case.
    https://gcc.gnu.org/pipermail/gcc-patches/2022-April/592981.html
    
v3: Add FIXME as Segher suggested.

[1] https://gcc.gnu.org/onlinedocs/gcc/Basic-PowerPC-Built-in-Functions-Available-on-ISA-2_002e05.html#Basic-PowerPC-Built-in-Functions-Available-on-ISA-2_002e05

BR,
Kewen
-----
	PR target/103623

gcc/ChangeLog:

	* config/rs6000/rs6000-builtins.def (__builtin_pack_longdouble): Add
	nosoft attribute.
	(__builtin_unpack_longdouble): Likewise.
	(__builtin_pack_ibm128): Likewise.
	(__builtin_unpack_ibm128): Likewise.

gcc/testsuite/ChangeLog:

	* gcc.target/powerpc/pr103623.c: New test.
---
 gcc/config/rs6000/rs6000-builtins.def       | 12 ++++--
 gcc/testsuite/gcc.target/powerpc/pr103623.c | 47 +++++++++++++++++++++
 2 files changed, 55 insertions(+), 4 deletions(-)
 create mode 100644 gcc/testsuite/gcc.target/powerpc/pr103623.c

--
2.27.0
diff mbox series

Patch

diff --git a/gcc/config/rs6000/rs6000-builtins.def b/gcc/config/rs6000/rs6000-builtins.def
index 0f527c5d78f..9170de35874 100644
--- a/gcc/config/rs6000/rs6000-builtins.def
+++ b/gcc/config/rs6000/rs6000-builtins.def
@@ -220,7 +220,8 @@ 
 ; This is redundant with __builtin_pack_ibm128, as it requires long
 ; double to be __ibm128.  Should probably be deprecated.
   const long double __builtin_pack_longdouble (double, double);
-    PACK_TF packtf {ibmld}
+; FIXME: Make this available for soft-float, see PR105213.
+    PACK_TF packtf {ibmld,nosoft}

   unsigned long __builtin_ppc_mftb ();
     MFTB rs6000_mftb_di {32bit}
@@ -235,18 +236,21 @@ 
     MTFSF rs6000_mtfsf {}

   const __ibm128 __builtin_pack_ibm128 (double, double);
-    PACK_IF packif {ibm128}
+; FIXME: Make this available for soft-float, see PR105213.
+    PACK_IF packif {ibm128,nosoft}

   void __builtin_set_fpscr_rn (const int[0,3]);
     SET_FPSCR_RN rs6000_set_fpscr_rn {nosoft}

   const double __builtin_unpack_ibm128 (__ibm128, const int<1>);
-    UNPACK_IF unpackif {ibm128}
+; FIXME: Make this available for soft-float, see PR105213.
+    UNPACK_IF unpackif {ibm128,nosoft}

 ; This is redundant with __builtin_unpack_ibm128, as it requires long
 ; double to be __ibm128.  Should probably be deprecated.
   const double __builtin_unpack_longdouble (long double, const int<1>);
-    UNPACK_TF unpacktf {ibmld}
+; FIXME: Make this available for soft-float, see PR105213.
+    UNPACK_TF unpacktf {ibmld,nosoft}


 ; Builtins that have been around just about forever, but not quite.
diff --git a/gcc/testsuite/gcc.target/powerpc/pr103623.c b/gcc/testsuite/gcc.target/powerpc/pr103623.c
new file mode 100644
index 00000000000..701db8bafa8
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/pr103623.c
@@ -0,0 +1,47 @@ 
+/* { dg-skip-if "" { powerpc*-*-darwin* } } */
+/* { dg-options "-mlong-double-128 -msoft-float" } */
+
+/* Verify there is no ICE.  */
+
+#include <stddef.h>
+#include <stdlib.h>
+#include <math.h>
+
+#if defined(__LONG_DOUBLE_IEEE128__)
+/* If long double is IEEE 128-bit, we need to use the __ibm128 type instead of
+   long double, and to use the appropriate pack/unpack routines.  We can't use
+   __ibm128 on systems that don't support IEEE 128-bit floating point, because
+   the type is not enabled on those systems.  */
+#define PACK __builtin_pack_ibm128
+#define UNPACK __builtin_unpack_ibm128
+#define LDOUBLE __ibm128
+
+#elif defined(__LONG_DOUBLE_IBM128__)
+#define PACK __builtin_pack_longdouble
+#define UNPACK __builtin_unpack_longdouble
+#define LDOUBLE long double
+
+#else
+#error "long double must be either IBM 128-bit or IEEE 128-bit"
+#endif
+
+extern LDOUBLE bar (LDOUBLE);
+
+int
+main (void)
+{
+  double high = pow (2.0, 60);
+  double low = 2.0;
+  LDOUBLE a = ((LDOUBLE) high) + ((LDOUBLE) low);
+  double x0 = UNPACK (a, 0);
+  /* Let's ignore all error messages about built-in function
+     unsupported due to soft-float, since they are not test
+     points here (this case is to check no ICE).  */
+  /* { dg-excess-errors "pr103623" } */
+  double x1 = UNPACK (a, 1);
+  LDOUBLE b = PACK (x0, x1);
+  LDOUBLE c = bar (b);
+
+  return c > a;
+}
+