Am 03.10.2011 10:24, schrieb Jonas Maebe:
On 03 Oct 2011, at 10:14, Florian Klämpfl wrote:
FPC doesn't do any optimization in procedures containing inline
assembler.
It does.
Oops, I thought you changed this a while ago :)
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fpc-devel maillist
Jonas Maebe schrieb:
It does. But also assumes that all registers are used in assembler
blocks, unless the programmer specifies otherwise.
But a:=a+1; does not imply any register usage, and the variable is a
global one?
DoDi
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fpc-devel maillis
2011/10/3 Jonas Maebe :
> asm nop end [];
>
> then the statement will optimized. Otherwise the compiler assumes that the
> contents of eax may still be used inside the assembler block and hence
> cannot remove its use.
>
> The fact that the optimization is performed in case the used register is ax
On 03 Oct 2011, at 10:14, Florian Klämpfl wrote:
FPC doesn't do any optimization in procedures containing inline
assembler.
It does. But also assumes that all registers are used in assembler
blocks, unless the programmer specifies otherwise. If you change the
assembler block into
asm
Am 03.10.2011 08:27, schrieb Alexander Klenin:
the following code:
{$mode objfpc}
var
a: Integer;
begin
a := a + 1;
asm nop end;
end.
generates (under -O2):
movlU_P$PROGRAM_A,%eax
incl%eax
movl%eax,U_P$PROGRAM_A
nop
instead of a single "incl
the following code:
{$mode objfpc}
var
a: Integer;
begin
a := a + 1;
asm nop end;
end.
generates (under -O2):
movlU_P$PROGRAM_A,%eax
incl%eax
movl%eax,U_P$PROGRAM_A
nop
instead of a single "incl".
removing either "asm" statement OR $mode directiv
