sparse-llvm: pseudo_to_value: Assertion `sym->ident == ((void *)0)' failed

sparse-llvm: pseudo_to_value: Assertion `sym->ident == ((void *)0)' failed

[Benjamin Herrenschmidt]

Hi folks !

Haven't had a chance to investigate further today (and probably won't)
so I'm shooting this here just in case ;-)

I was tracking down what looks like an LLVM bug with sign extension from
1-bit integers while playing with llvmpipe (gallium llvm backend) and
out of curiosity decided to look at what sparse generated when
sign-extending a bool :-)

So I added to my earlier hello.c some statements to that effect, and
trying to compile it results in:

sparse-llvm.c:311: pseudo_to_value: Assertion `sym->ident == ((void *)0)' failed.

The new hello.c is:

#include <stdio.h>
#include <stdbool.h>

int main(void)
{
        int i;
        double f1,f2;
        bool eq;

        printf("Hello World !\n");

        for (i = 0; i < 10; i ++)
                printf("I can count to %d\n", i);

        printf("f1=");
        scanf("%f",&f1);
        printf("f2=");
        scanf("%f",&f2);

        eq = f1 == f2;

        printf("f1==f2: %d\n", (int)eq);
        return 0;
}

Cheers,
Ben.

Re: sparse-llvm: pseudo_to_value: Assertion `sym->ident == ((void *)0)' failed

[Pekka Enberg]

On Mon, Feb 13, 2012 at 9:17 AM, Benjamin Herrenschmidt
<benh@kernel.crashing.org> wrote:
> Hi folks !
>
> Haven't had a chance to investigate further today (and probably won't)
> so I'm shooting this here just in case ;-)
>
> I was tracking down what looks like an LLVM bug with sign extension from
> 1-bit integers while playing with llvmpipe (gallium llvm backend) and
> out of curiosity decided to look at what sparse generated when
> sign-extending a bool :-)
>
> So I added to my earlier hello.c some statements to that effect, and
> trying to compile it results in:
>
> sparse-llvm.c:311: pseudo_to_value: Assertion `sym->ident == ((void *)0)' failed.
>
> The new hello.c is:
>
> #include <stdio.h>
> #include <stdbool.h>
>
> int main(void)
> {
>        int i;
>        double f1,f2;
>        bool eq;
>
>        printf("Hello World !\n");
>
>        for (i = 0; i < 10; i ++)
>                printf("I can count to %d\n", i);
>
>        printf("f1=");
>        scanf("%f",&f1);
>        printf("f2=");
>        scanf("%f",&f2);
>
>        eq = f1 == f2;
>
>        printf("f1==f2: %d\n", (int)eq);
>        return 0;
> }

I can reproduce the issue with this minimal test case:

#include <stdio.h>

int main(int argc, char *argv[])
{
	float f;

	scanf("%f", &f);

	return 0;
}

It looks like we need to teach pseudo_to_value() about ident symbols.

                        Pekka
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