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[Bug inline-asm/43998] inline assembler: can't set clobbering for input register
- From: "ebotcazou at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 14 May 2010 07:10:49 -0000
- Subject: [Bug inline-asm/43998] inline assembler: can't set clobbering for input register
- References: <bug-43998-17114@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #12 from ebotcazou at gcc dot gnu dot org 2010-05-14 07:10 -------
> the compiler may think that "something" do not modify eax. So next assignment
> may use eax ( mov eax, x ). So, "it does not make sense to have it as a
> clobber" is not correct. does not it ?
Andrew was saying that it doesn't make sense to consider input operands as
clobbered by an inline asm, generically.
> And the second, "Because the way the constraints are implemented inside GCC,
> an input constraint cannot overlap with a clobber." - It definitely the bug.
No, it isn't, it's clearly stated in the manual: "You may not write a clobber
description in a way that overlaps with an input or output operand."
--
ebotcazou at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |ebotcazou at gcc dot gnu dot
| |org
Status|UNCONFIRMED |RESOLVED
Resolution| |INVALID
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43998