LLVM+Clang 3.3: clang: for the -vectorize-loops option: may only occur zero or one times!

Hi,

My application generates some C code which I then compile using LLVM+Clang before running it. For the compilation side of things, I have a class which one of the methods (the CompilerEngine::compileCode() method in https://raw.github.com/opencor/opencor/llvm_3.3/src/plugins/misc/Compiler/src/compilerengine.cpp) is based on the code from the clang-interpreter example (http://llvm.org/viewvc/llvm-project/cfe/trunk/examples/clang-interpreter/main.cpp?view=co). The idea is therefore to create an instance of the ‘compiler’ class and, among other things, use its compileCode() whenever needed.

All of this works perfectly fine using LLVM+Clang 3.2, but not with LLVM+Clang 3.3. At least, not out of the box. Basically, the first time I try to compile some C code, everything is fine. However, if I try to compile some other C code, then I will get the following error message:

clang: for the -vectorize-loops option: may only occur zero or one times!

FWIW, I use the -O3 option which I understand makes implicit use of the loop vectorizer, and that seems to be the problem. Indeed, if I disable the loop vectorizer (using the -fno-vectorize option), then everything is fine but I clearly don’t want to have to do that. So, right now, my solution consists of commenting out the test for the number of option occurrences in the Option::addOccurrence() method (http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Support/CommandLine.cpp?view=co), but it is clearly not satisfactory either (even though it’s good enough for my particular purpose).

So, would anyone have any idea about what I might be missing, if anything?..

Cheers, Alan.

Hi,

I can confirm this problem. We use clang's libtooling ToolInvocation object
and the second module fails to compile even through it's a completely fresh
instance.

Adding -fno-vectorize explicitly seems to work around this problem, but
does anyone know a real fix?

ciao,
Mario

Thanks Mario, it's good (so to speak!) to know that I am not the only one
experiencing this problem!

I have had another look at the LLVM code and, as far as I can tell, it would
seem that it's related to llvm::cl:: RegisteredOptionList not being properly
reset or something. Anyway, I want to be able to take advantage of the loop
vectorizer, so I have decided to comment out the test for the number of
option occurrences in the Option::addOccurrence() method
(http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Support/CommandLine.cpp?
view=co). Not nice, but it seems to be doing the job for me and, unless I am
told/shown otherwise, there doesn't seem to be any other solution, so...

Alan

From: Mario Schwalbe [mailto:m3o.s6e@googlemail.com]
Sent: 21 June 2013 10:32
To: Alan Garny
Cc: LLVM Dev; Clang Dev; Mario Schwalbe
Subject: Re: [LLVMdev] LLVM+Clang 3.3: clang: for the -vectorize-loops

option:

may only occur zero or one times!

Hi,

I can confirm this problem. We use clang's libtooling ToolInvocation

object

and the second module fails to compile even through it's a completely

fresh

instance.

Adding -fno-vectorize explicitly seems to work around this problem, but

does

anyone know a real fix?

ciao,
Mario

> My application generates some C code which I then compile using
LLVM+Clang before running it. For the compilation side of things, I have a
class which one of the methods (the CompilerEngine::compileCode() method
in
https://raw.github.com/opencor/opencor/llvm_3.3/src/plugins/misc/Compiler
/sr c/compilerengine.cpp) is based on the code from the clang-interpreter
example (http://llvm.org/viewvc/llvm-project/cfe/trunk/examples/clang-
interpreter/ma in.cpp?view=co). The idea is therefore to create an

instance of

the 'compiler' class and, among other things, use its compileCode()

whenever

needed.
>
> All of this works perfectly fine using LLVM+Clang 3.2, but not with
LLVM+Clang 3.3. At least, not out of the box. Basically, the first time I

try to

compile some C code, everything is fine. However, if I try to compile some
other C code, then I will get the following error message:
>
> clang: for the -vectorize-loops option: may only occur zero or one

times!

>
> FWIW, I use the -O3 option which I understand makes implicit use of the
loop vectorizer, and that seems to be the problem. Indeed, if I disable

the

loop vectorizer (using the -fno-vectorize option), then everything is fine

but I

clearly don't want to have to do that. So, right now, my solution consists

of

commenting out the test for the number of option occurrences in the
Option::addOccurrence() method (http://llvm.org/viewvc/llvm-
project/llvm/trunk/lib/Support/CommandLine.cpp? view=co), but it is

clearly