Fix assembly errors:
.../libphobos/src/std/math.d: Assembler messages:.../libphobos/src/std/math.d:4773: Error: unrecognized opcode `frflags a0'.../libphobos/src/std/math.d:4856: Error: unrecognized opcode `fsflags a5'.../libphobos/src/std/math.d:4856: Error: unrecognized opcode `fsflags a5'.../libphobos/src/std/math.d:4773: Error: unrecognized opcode `frflags a0'.../libphobos/src/std/math.d:5549: Error: unrecognized opcode `fscsr a5'.../libphobos/src/std/math.d:5456: Error: unrecognized opcode `frcsr a5'.../libphobos/src/std/math.d:5456: Error: unrecognized opcode `frcsr a5'.../libphobos/src/std/math.d:5549: Error: unrecognized opcode `fscsr a5'.../libphobos/src/std/math.d:5456: Error: unrecognized opcode `frcsr a5'.../libphobos/src/std/math.d:5549: Error: unrecognized opcode `fscsr a0'.../libphobos/src/std/math.d:5456: Error: unrecognized opcode `frcsr a0'.../libphobos/src/std/math.d:5456: Error: unrecognized opcode `frcsr a0'.../libphobos/src/std/math.d:5549: Error: unrecognized opcode `fscsr s2'make[8]: *** [Makefile:1119: std/math.lo] Error 1
triggered with the RISC-V lp64 multilib in a GCC build configured with
`--enable-multilib --enable-languages=all --target=riscv64-linux-gnu'.
This is due to unconditional explicit use of F extension instructions
within inline assembly, to access IEEE exception flags. The use of
these instructions is not allowed when building for a soft-float ABI.
Correct the problem by wrapping said inline assembly into a conditional
such that if `D_SoftFloat' is true, then reads from IEEE exception flags
return 0 and writes are ignored instead, complementing r270522
("libphobos: Add D support for RISC-V Linux"), which is an updated
version of <https://gcc.gnu.org/ml/gcc-patches/2019-04/msg00325.html>,
where the problematic code has originated from.
libphobos/ChangeLog:
2019-05-02 Maciej W. Rozycki <macro@wdc.com>
* std/math.d (IeeeFlags.getIeeeFlags): Handle RISC-V soft-float ABI.
(IeeeFlags.resetIeeeFlags): Likewise.
(FloatingPointControl.getControlState): Likewise.
(FloatingPointControl.setControlState): Likewise.
From-SVN: r270815
