Print value of __m128 datatype in gdb debugger

Question

Is there any way to print the value of a variable of datatype __m128 (used for Intel SSE intrinsics) directly in GDB? The command print $myVariable works fine for int and float but not for __m128.

Answer 1

It's a pain, but I usually do it like this:

gdb> p *(float *)&v@4

This is assuming that v is __m128. You can apply the same principle for e.g. an __m128i vector of unsigned char:

gdb> p /x *(unsigned char *)&v@16