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extend.texi (Extended Asm): Mention that a memory clobber does not count as a side-effect.

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* extend.texi (Extended Asm): Mention that a memory clobber
does not count as a side-effect.

From-SVN: r35110
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Geoff Keating 2000-07-18 00:23:50 +00:00 committed by Geoffrey Keating
parent 5b1a6de4de
commit dd40655a26
2 changed files with 7 additions and 1 deletions
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@ -1,5 +1,8 @@
2000-07-17 Geoffrey Keating <geoffk@cygnus.com>
* extend.texi (Extended Asm): Mention that a memory clobber
does not count as a side-effect.
* unroll.c (copy_loop_body): Fix one instance of using host
arithmetic on the target; fixes loop-4 on a 32-bit -> 64-bit
cross-compile.

5
gcc/extend.texi
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@ -2558,7 +2558,10 @@ effect. But it is valid no matter what the machine.
If your assembler instruction modifies memory in an unpredictable
fashion, add @samp{memory} to the list of clobbered registers. This
will cause GNU CC to not keep memory values cached in registers across
the assembler instruction.
the assembler instruction. You will also want to add the
@code{volatile} keyword if the memory affected is not listed in the
inputs or outputs of the @code{asm}, as the @samp{memory} clobber does
not count as a side-effect of the @code{asm}.
You can put multiple assembler instructions together in a single
@code{asm} template, separated either with newlines (written as