CODEWITHSUNDEEP
cqtgccx86sse
user24205
user24205

Reputation: 502

SIMD Instructions in Qt Creator

I am working with a company to create a specialized set of codes that use SSE instructions. They are using the Qt Creator IDE. I have provided them with a C header file and corresponding *.c file that compile in XCode and Visual Studio; they don't compile in Qt Creator.

How do I alter the appropriate compiler settings so that SSE instructions will compile in Qt Creator?

The line causing the first error is as follows:

_mm_store_ps(outData, _mm_add_ps(*l, *r));

The error statements read:

Inlining failed in call to always_inline ‘__mm_add_ps’: target specific option mismatch
Inlining failed in call to always_inline ‘_mm_store_ps’: target specific option mismatch

We're also getting this warning:

SSE vector return without SSE enabled changes the ABI [-Wpsabi]

Upvotes: 0

Views: 2237

Answers (1)

Peter Cordes
Peter Cordes

Reputation: 365237

Compilers like gcc and clang require that the relevant instruction-set extensions be enabled when compiling code that uses intrinsics and vector types. e.g. -msse2. This also lets the compiler auto-vectorize with SSE2.

SSE2 is baseline for x86-64, so I guess you're building a 32-bit binary for some reason?

I think some compilers (maybe MSVC) will let you use intrinsics without enabling the compiler to automatically generate the instructions.

If you want to do runtime CPU dispatching, so you have some functions that use SSE4.1 or AVX, but need your program to work on computers without those: put your SSE4 and AVX functions in separate files, so you can build those compilation units with -msse4.1 and -mavx.

It's usually a good idea to enable -march=nehalem or -march=haswell to also enable stuff like -mpopcnt (if that's what you want), and more importantly to set -mtune=haswell to optimize for a likely target CPU as well as using extensions it supports.

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Upvotes: 3

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