Qt, GCC, SSE and stack alignment

Question

I\'m trying to make a program compiled with GCC and using Qt and SSE intrinsics. It seems that when one of my functions is called by Qt, the stack alignment is not preserved

Answer 1

__attribute__((force_align_arg_pointer)) void paintEvent(QPaintEvent *);

made it work! Does anybody have a better solution?

Answer 2

You can use the option -mstackrealign to do that without adding attributes to your source code:

-mstackrealign Realign the stack at entry. On the Intel x86, the -mstackrealign option will generate an alternate prologue and epilogue that realigns the runtime stack if necessary. This supports mixing legacy codes that keep a 4-byte aligned stack with modern codes that keep a 16-byte stack for SSE compatibility. See also the attribute force_align_arg_pointer, applicable to individual functions.

(from the GCC docs)