On 9/10/25 9:29 AM, Jakub Jelinek wrote:
On Mon, Sep 08, 2025 at 07:44:39PM +0200, Jakub Jelinek wrote:
On Mon, Sep 08, 2025 at 06:14:06PM +0200, Jakub Jelinek wrote:
Yet another option would be keep doing what we were doing unless
GET_MODE_PRECISION is 80, in which case deal with the 2 variants based on
signbit_ro value.
Here it is, tested on all of x86_64-linux (-m32/-m64), m68k-linux cross
(-mc68020) and x86_64-freebsd13.0 (-m32/-m64).
Ok for trunk if it passes full bootstrap/regtest?
Here is a new version, the only difference is abi_version_at_least
change to abi_check, so that we emit the mangling aliases for now (they
can be emitted just fine because the mangling included mangled type
(e) plus previously were always 4 or 12 hex digits longer, so it can't
clash with other long double literals or _Float128/__float128 literals
in the mangled names.
Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
2025-09-10 Jakub Jelinek <[email protected]>
* mangle.cc (write_real_cst): Mangle Intel/Motorola extended
80-bit formats using 20 hex digits instead of 24 or 32.
* g++.target/i386/mangle-ldbl-1.C: New test.
* g++.target/i386/mangle-ldbl-2.C: New test.
It looks like these tests won't run on m68k, can you make at least the
-2 test run (and pass) there?
--- gcc/cp/mangle.cc.jj 2025-09-02 17:02:44.128176211 +0200
+++ gcc/cp/mangle.cc 2025-09-09 09:43:09.422358069 +0200
@@ -2190,6 +2190,29 @@ write_real_cst (const tree value)
else
i = words - 1, limit = -1, dir = -1;
+ if (GET_MODE_PRECISION (SCALAR_FLOAT_TYPE_MODE (type)) == 80
+ && abi_check (21))
+ {
+ /* For -fabi-version=21 and above mangle
+ Intel/Motorola extended format 1.0L as
+ 3fff8000000000000000
+ rather than the previous
+ 0000000000003fff8000000000000000 (x86_64)
+ 00003fff8000000000000000 (ia32)
+ 3fff00008000000000000000 (m68k -mc68020)
+ i.e. without any embedded padding bits. */
+ if (words == 4)
+ i += dir;
+ else
+ gcc_assert (words == 3);
+ unsigned long val = (unsigned long) target_real[i];
+ if (REAL_MODE_FORMAT (SCALAR_FLOAT_TYPE_MODE (type))->signbit_ro == 95)
+ val >>= 16;
+ sprintf (buffer, "%04lx", val);
+ write_chars (buffer, 4);
+ i += dir;
+ }
+
for (; i != limit; i += dir)
{
sprintf (buffer, "%08lx", (unsigned long) target_real[i]);
--- gcc/testsuite/g++.target/i386/mangle-ldbl-1.C.jj 2025-09-08
19:34:51.143198289 +0200
+++ gcc/testsuite/g++.target/i386/mangle-ldbl-1.C 2025-09-08
19:36:17.033063950 +0200
@@ -0,0 +1,8 @@
+// { dg-do compile { target { c++20 && { x86_64-*-linux* i?86-*-linux* } } } }
+// { dg-final { scan-assembler "_Z3fooILe3fff8000000000000000EEiv" } }
+// { dg-final { scan-assembler "_Z3fooILe40008000000000000000EEiv" } }
+
+template <long double a>
+int foo () { return 0; }
+
+int bar () { return foo <1.0L> () + foo <2.0L> (); }
--- gcc/testsuite/g++.target/i386/mangle-ldbl-2.C.jj 2025-09-08
19:36:24.505965257 +0200
+++ gcc/testsuite/g++.target/i386/mangle-ldbl-2.C 2025-09-08
19:38:56.977951557 +0200
@@ -0,0 +1,11 @@
+// { dg-do compile { target { c++20 && { x86_64-*-linux* i?86-*-linux* } } } }
+// { dg-additional-options "-fabi-version=20" }
+// { dg-final { scan-assembler "_Z3fooILe0000000000003fff8000000000000000EEiv"
{ target { ! ia32 } } } }
+// { dg-final { scan-assembler "_Z3fooILe00000000000040008000000000000000EEiv"
{ target { ! ia32 } } } }
+// { dg-final { scan-assembler "_Z3fooILe00003fff8000000000000000EEiv" {
target ia32 } } }
+// { dg-final { scan-assembler "_Z3fooILe000040008000000000000000EEiv" {
target ia32 } } }
+
+template <long double a>
+int foo () { return 0; }
+
+int bar () { return foo <1.0L> () + foo <2.0L> (); }
Jakub
