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On my M1 iMac 24” 2021 using vDSP_DFT_SetupD() to create a new vDSP_DFT_SetupD structure that is half the size of the previous one causes vDSP_DFT_ExecuteD() to crash. This issue does not affect the x86_64 executable, which runs correctly on x86_64 hardware and under Rosetta emulation.

The attached command line tool demonstrates the problem. When run the results expected are:

    Starting
    Setup 1 created
    Setup 1 executed
    Setup 2 created
    Setup 1 destroyed
    Setup 2 executed
    Setup 2 destroyed
    Finished
    Program ended with exit code: 0

The results I actually see on M1 hardware are:

    Starting
    Setup 1 created
    Setup 1 executed
    Setup 2 created
    Setup 1 destroyed
    zsh: segmentation fault  ./DFTbug

With the stack trace in Xcode:

    Thread 1: EXC_BAD_ACCESS (code=1, address=0x10)
    #0	0x00000001b230a92c in ___lldb_unnamed_symbol1320 ()
    #1	0x00000001b22adf3c in ___lldb_unnamed_symbol909 ()
    #2	0x0000000100003ec0 in main at /Users/cdhw/Downloads/DFTbug/DFTbug/main.c:28
    #3	0x000000010001508c in start ()

I’ve pasted code below for a short command line tool that demonstrates the issue.

A workaround is to use NULL instead of a previous vDSP_DFT_SetupD structure but this has severe speed penalty in practice.



//
//  main.c
//  DFTbug
//
//  Created by Charles Williams on 07/10/2022.
//

#include <stdio.h>
#include <Accelerate/Accelerate.h>

int main(int argc, const char * argv[]) {
    int N = 1024*1024;
    double * out_real = calloc(N,sizeof(double));
    double * out_imag = calloc(N,sizeof(double));
    double * inp_real = calloc(N,sizeof(double));
    double * inp_imag = calloc(N,sizeof(double));

    printf("Starting\n");
    
    vDSP_DFT_SetupD setup_1 = vDSP_DFT_zop_CreateSetupD(NULL, N, vDSP_DFT_INVERSE );
    printf("Setup 1 created\n");
    vDSP_DFT_ExecuteD( setup_1, out_real, out_imag, inp_real, inp_imag);
    printf("Setup 1 executed\n");
    vDSP_DFT_SetupD setup_2 = vDSP_DFT_zop_CreateSetupD(setup_1, N/2, vDSP_DFT_INVERSE );
    printf("Setup 2 created\n");
    vDSP_DFT_DestroySetupD(setup_1);
    printf("Setup 1 destroyed\n");
    vDSP_DFT_ExecuteD( setup_2, out_real, out_imag, inp_real, inp_imag);
    printf("Setup 2 executed\n");
   vDSP_DFT_DestroySetupD(setup_2);
    printf("Setup 2 destroyed\n");

    printf("Finished\n");

    return 0;
}