MSPM0G3507: arm-none-eabi-gcc 10.3.1 combination of -O1 and -flto removes interrupt vector table and other functions (MSPM0 SDK 1.20.0.5)

Hello,

we are using arm-none-eabi-gcc to cross build for MSPM0G3507 MCU. The version set is

• arm-none-eabi-gcc: 10.3.1
• MSPM0 SDK: 1.20.0.5

If using compiler settings -O0 and -flto code runs as expected.

If using -O1/2/s and -flto the binary gets suspiciously small and when downloaded kind of "bricks" the MCU .. at least I cannot access it via SWD anymore.

As a root cause I figured that the interruptVectors table in the startup_mspm0g3507_gcc.c is completely removed from the binary.

If I change 

void (*const interruptVectors[])(void) __attribute__((section(".intvecs"))) = {
    (pFunc)&__StackTop, /* The initial stack pointer */
    Reset_Handler,      /* The reset handler         */
    NMI_Handler,        /* The NMI handler           */

to 

void (*const interruptVectors[])(void) __attribute__((section(".intvecs"), used)) = {
    (pFunc)&__StackTop, /* The initial stack pointer */
    Reset_Handler,      /* The reset handler         */
    NMI_Handler,        /* The NMI handler           */
    HardFault_Handler,  /* The hard fault handler    */
    0,                  /* Reserved                  */

the interruptVectors table is not removed anymore and the code runs. As this modification regards the GCC specific startup file I am fine modifying it.

Yet also the function void DL_Common_delayCycles(uint32_t cycles) in dl_common.c is getting removed when using -O1/2/s and -flto. So still the code shows unexpected behavior in some locations.

I don't want to do modifications in the TI driver lib like setting compiler specific attributes like I did in the startup file.

Any suggestions how to approach this issue? LTOs are absolutely necessary in our project ...

Is there any statement from TI on what arm-none-eabi-gcc versions and optimization options are supported given a specific  MSPM0 SDK?

Any changes the interruptVectors table will be marked with the used attribute in next MSPM0 SDK releases?

Best Regards 

Marco