[LLVMdev] inline asm constraints in LLVM

[John Thompson]

I'm trying to fix the handling of multiple alternate constraints in Clang
(see
http://gcc.gnu.org/onlinedocs/gcc/Multi_002dAlternative.html#Multi_002dAlternative
).

How should the constraints be represented in the .ll file?

Clang currently will assert because the code generator sees a constraints
string with the wrong number of comma-separated items.

Basically, after some editing, it just concatenates them together.  The
commas used in the string for a multiple alternative constraint gets
confused with the commas separating the constraints.

Briefly looking at the LLVM asm parser, I can't really see anything that
tells me multiple alternative constraints are supported.

But if they are, please tell me the string format, and perhaps update the
docs to show this.

If they are not yet supported in LLVM, what should I do?

-John

-- 
John Thompson
John.Thompson.JTSoftware at gmail.com
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