Forums - Problem with LLVM 3.6 when Loading and Storing

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Problem with LLVM 3.6 when Loading and Storing
andre.trofino
Join Date: 13 Apr 15
Posts: 2
Posted: Mon, 2015-06-29 13:37
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Hello,

I made simple code to test inline NEON assembly using LLVM 3.6:
void jmpTest(float *a) {

    float b[4] = {1.0, 2.0, 3.0, 4.0};

    asm (
            "vld1.f32 q0, [%[b]]    \n\t"
            "mov r1, #2                \n\t"
            "vdup.f32 q1, r1        \n\t"
            "vmul.f32 q0, q0, q1       \n\t"
            "vst1.f32 q0, [%[a]]    \n\t"
        :
        : [a] "r" (a), [b] "r" (b)
        : "memory", "r1", "q0", "q1"
    );
}

But i get this error:

Error: Neon quad precision register expected -- `vld1.f32 q0,[r2]'
Error: Neon quad precision register expected -- `vst1.f32 q0,[r0]'

it only happens when i try to load or store C++ variables. Also, this was not happening when i was using LLVM 3.5.

The syntax is the same as i have seen around the internet, what is it that it's not working?

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Re: Problem with LLVM 3.6 when Loading and Storing
andre.trofino
Join Date: 13 Apr 15
Posts: 2
Posted: Wed, 2015-07-01 04:14
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I've solved this problem by replacing "q0" in the store and load instructions for "{d0,d1}"

            "vld1.f32 {d0,d1}, [%[b]]    \n\t"
            "mov r1, #2                \n\t"
            "vdup.f32 q1, r1        \n\t"
            "vmul.f32 q0, q0, q1       \n\t"
            "vst1.f32 {d0,d1}, [%[a]]    \n\t"
        :
        : [a] "r" (a), [b] "r" (b)
        : "memory", "r1", "q0", "q1"

I have no idea why 3.6 doesn't accept the other one, by this way it works

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