Not sure if this is valgrind, me or DMD so thought I should report it. Program runs, so could be just valgrind.
It causes valgrind grief when casting a mutable double variable to a ubyte variable. Casting a literal floating point value worked, as did an immutable double variable.
------------------------
void main()
{
double dval = 123.456;
ubyte ubvalFAIL = cast(ubyte)(dval); // Causes the problem.
ubyte ubvalOK = cast(ubyte)(123.456); // This cast works if above line commented out.
}
------------------------
Given the second cast worked I tried the following and it worked also:
void main() {
immutable double dval = 123.456;
ubyte ubvalOK = cast(ubyte)(dval); // Happy valgrind.
}
=============================================
$ objdump -d quicktest | grep "41652e" -n8
427- 41650c: f2 48 0f 10 05 ab 77 rex.W movsd 0x177ab(%rip),%xmm0 # 42dcc0 <__dso_handle+0x8>
428- 416513: 01 00
429- 416515: f2 48 0f 11 45 f0 rex.W movsd %xmm0,-0x10(%rbp)
430- 41651b: dd 45 f0 fldl -0x10(%rbp)
431- 41651e: 50 push %rax
432- 41651f: d9 7c 24 02 fnstcw 0x2(%rsp)
433- 416523: 66 c7 44 24 04 bf 0f movw $0xfbf,0x4(%rsp)
434- 41652a: d9 6c 24 04 fldcw 0x4(%rsp)
435: 41652e: 48 df 1c 24 rex.W fistp (%rsp) <<<< HERE
436- 416532: 48 d9 6c 24 02 rex.W fldcw 0x2(%rsp)
437- 416537: 58 pop %rax
438- 416538: 88 45 f8 mov %al,-0x8(%rbp)
439- 41653b: 31 c0 xor %eax,%eax
440- 41653d: c9 leaveq
441- 41653e: c3 retq
442- 41653f: 90 nop
443- 416540: c8 00 00 00 enterq $0x0,$0x0
============================================================================
VALGRIND OUTPUT (abbrev.)
------------------------
vex amd64->IR: unhandled instruction bytes: 0x48 0xDF 0x1C 0x24 0x48 0xD9 0x6C 0x24
vex amd64->IR: REX=1 REX.W=1 REX.R=0 REX.X=0 REX.B=0
vex amd64->IR: VEX=0 VEX.L=0 VEX.nVVVV=0x0 ESC=NONE
vex amd64->IR: PFX.66=0 PFX.F2=0 PFX.F3=0
==2323== valgrind: Unrecognised instruction at address 0x4176fe.
==2323== at 0x4176FE: _Dmain (/tmp/quicktest.d:18)
...
...
==2323== Your program just tried to execute an instruction that Valgrind
==2323== did not recognise. There are two possible reasons for this.
==2323== 1. Your program has a bug and erroneously jumped to a non-code
==2323== location. If you are running Memcheck and you just saw a
==2323== warning about a bad jump, it's probably your program's fault.
==2323== 2. The instruction is legitimate but Valgrind doesn't handle it,
==2323== i.e. it's Valgrind's fault. If you think this is the case or
==2323== you are not sure, please let us know and we'll try to fix it.
==2323== Either way, Valgrind will now raise a SIGILL signal which will
==2323== probably kill your program.
===========================
Thanks.
Comment #1 by maxim — 2013-05-09T22:03:49Z
This is Valgrind issue. Some of x87 float instructions are not recognized by it.