Re: xemacs coredump in M-x eval-print-last-sexp

I agree with Jerry. On the Arm it is prefetching the pointer before doing the branch not equal. It has *something* to do with the casts. If you take the gcc output and remove all the silly casts and brackets you get the following: if (var.gu.type == Lisp_Type_Record && ((struct lrecord_header*)var.ui)->type == lrecord_type_symbol) 10e4: e2153003 ands r3, r5, #3 ; 0x3 10e8: e1a02003 mov r2, r3 10ec: e5d53000 ldrb r3, [r5] <- bad instruction! bad! 10f0: 1a000441 bne 21fc <signal_1+0x4c4> Which crashes :-( It loads r5 indirect before the branch. However, remove the struct cast and replace it with a simple unsigned: if (var.gu.type == Lisp_Type_Record && (*((unsigned*)var.ui) & 0xff) == lrecord_type_symbol) 10e4: e2153003 ands r3, r5, #3 ; 0x3 10e8: e1a02003 mov r2, r3 10ec: 1a000441 bne 21f8 <signal_1+0x4c0> 10f0: e5d53000 ldrb r3, [r5] And it works :-) Notice that the indirect load is now after the branch. Note this also explains why the use_union_type flag is irrelevant here. It only affects the first part of the if, not the casting part. I don't know where to go from here. I suppose RECORD_TYPEP could be modified to do the above cast but I am way out of my depth here. Cheers, Sean P.S. I love the great comment that tells you that 3 decimal is 3 hex. I learn something new everyday.