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+ always do the x86_64 reference optimizations as if SS=DS, because the CPU

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basically ignores these segments in long mode

git-svn-id: trunk@37515 -
This commit is contained in:
nickysn 2017-10-24 15:38:59 +00:00
parent e58bad8eef
commit 5ae32a0ec5
1 changed files with 14 additions and 0 deletions
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14
compiler/x86/aasmcpu.pas
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@ -1873,10 +1873,24 @@ implementation
var
ss_equals_ds: boolean;
begin
{$ifdef x86_64}
{ x86_64 in long mode ignores all segment base, limit and access rights
checks for the DS, ES and SS registers, so we can set ss_equals_ds to
true (and thus, perform stronger optimizations on the reference),
regardless of whether this is inline asm or not (so, even if the user
is doing tricks by loading different values into DS and SS, it still
doesn't matter while the processor is in long mode) }
ss_equals_ds:=True;
{$else x86_64}
{ for i8086 and i386 inline asm, we assume SS<>DS, even if we're
compiling for a memory model, where SS=DS, because the user might be
doing something tricky with the segment registers (and may have
temporarily set them differently) }
if inlineasm then
ss_equals_ds:=False
else
ss_equals_ds:=segment_regs_equal(NR_DS,NR_SS);
{$endif x86_64}
{ remove redundant segment overrides }
if (ref.segment<>NR_NO) and
((inlineasm and (ref.segment=get_default_segment_of_ref(ref))) or