newlib: Fix long double for unsupported rounding modes and exceptions

RISC-V newlib fails to build for soft float multilibs since long double
support was enabled in:

  commit 04798b7bb69571452d2cfc7e0b052a9bbd3b619d
  Author: Kito Cheng <kito.cheng@sifive.com>
  Date:   Mon Dec 4 15:41:39 2023 +0800

      RISC-V: Support long double math

      Long double for RISC-V is using 128 bit IEEE 754 format like Aarch64,
      so we reference AArch64 to support that.

The RISC-V soft floating point environment only supports the
FE_TONEAREST rounding mode and does not support exceptions.  Guard long
double rounding and exception support with ifdefs based on the presence
of the relevant rounding modes and exceptions.

Tested on gcc/g++ testsuite using RISC-V GNU Newlib Toolchain built by
riscv-gnu-toolchain with multilibs:

    riscv-sim/-march=rv32i/-mabi=ilp32/-mcmodel=medlow
    riscv-sim/-march=rv32iac/-mabi=ilp32/-mcmodel=medlow
    riscv-sim/-march=rv32im/-mabi=ilp32/-mcmodel=medlow
    riscv-sim/-march=rv32imac/-mabi=ilp32/-mcmodel=medlow
    riscv-sim/-march=rv32imafc/-mabi=ilp32f/-mcmodel=medlow
    riscv-sim/-march=rv64imac/-mabi=lp64/-mcmodel=medlow

Co-authored-by: Simon Cook <simon.cook@embecosm.com>

diff --git a/newlib/libm/ld/s_fmal.c b/newlib/libm/ld/s_fmal.c
index a379346c171f042caa7606892dcb2b03f52c0881..281dd685b3fcd3676965c1fa68b624e044ff362f 100644 (file)
--- a/newlib/libm/ld/s_fmal.c
+++ b/newlib/libm/ld/s_fmal.c
@@ -199,27 +199,37 @@ fmal(long double x, long double y, long double z)
         * modes other than FE_TONEAREST are painful.
         */
        if (spread < -LDBL_MANT_DIG) {
+#ifdef FE_INEXACT
                feraiseexcept(FE_INEXACT);
+#endif
+#ifdef FE_UNDERFLOW
                if (!isnormal(z))
                        feraiseexcept(FE_UNDERFLOW);
+#endif
                switch (oround) {
-               case FE_TONEAREST:
+               default: /* FE_TONEAREST */
                        return (z);
+#ifdef FE_TOWARDZERO
                case FE_TOWARDZERO:
                        if (x > 0.0 ^ y < 0.0 ^ z < 0.0)
                                return (z);
                        else
                                return (nextafterl(z, 0));
+#endif
+#ifdef FE_DOWNWARD
                case FE_DOWNWARD:
                        if (x > 0.0 ^ y < 0.0)
                                return (z);
                        else
                                return (nextafterl(z, -INFINITY));
-               default:        /* FE_UPWARD */
+#endif
+#ifdef FE_UPWARD
+               case FE_UPWARD:
                        if (x > 0.0 ^ y < 0.0)
                                return (nextafterl(z, INFINITY));
                        else
                                return (z);
+#endif
                }
        }
        if (spread <= LDBL_MANT_DIG * 2)

diff --git a/newlib/libm/ld/s_lrint.c b/newlib/libm/ld/s_lrint.c
index ad9b978fa8f427d512f0ad4a60a08827ca168b04..dde3cc434624d29d11ba522ad4d351b120df5953 100644 (file)
--- a/newlib/libm/ld/s_lrint.c
+++ b/newlib/libm/ld/s_lrint.c
@@ -53,8 +53,10 @@ fn(type x)
 
        feholdexcept(&env);
        d = (dtype)roundit(x);
+#if defined(FE_INVALID) && defined(FE_INEXACT)
        if (fetestexcept(FE_INVALID))
                feclearexcept(FE_INEXACT);
+#endif
        feupdateenv(&env);
        return (d);
 }

diff --git a/newlib/libm/ld/s_lround.c b/newlib/libm/ld/s_lround.c
index f67f9fbeb5d7d3fce46a22caa27137bad7be20df..fefafa877de05e70ab1b8afda48356455b997ff5 100644 (file)
--- a/newlib/libm/ld/s_lround.c
+++ b/newlib/libm/ld/s_lround.c
@@ -64,7 +64,9 @@ fn(type x)
                x = roundit(x);
                return ((dtype)x);
        } else {
+#ifdef FE_INVALID
                feraiseexcept(FE_INVALID);
+#endif
                return (DTYPE_MAX);
        }
 }