http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49798
Summary: .quad instead of .long is used for address for x32 Product: gcc Version: 4.7.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: middle-end AssignedTo: unassig...@gcc.gnu.org ReportedBy: hjl.to...@gmail.com --- union U { int *m; double d; }; extern int xxxx; int foo (union U u) { union U v = { &xxxx}; return u.d == v.d; } --- I got [hjl@gnu-6 gcc]$ ./xgcc -B./ -mx32 -O2 -S x.c [hjl@gnu-6 gcc]$ cat x.s .file "x.c" .text .p2align 4,,15 .globl foo .type foo, @function foo: .LFB0: .cfi_startproc movq %rdi, -8(%rsp) movsd .LC0(%rip), %xmm1 movsd -8(%rsp), %xmm0 movl $1, %eax ucomisd %xmm1, %xmm0 jp .L3 jne .L3 rep ret .p2align 4,,10 .p2align 3 .L3: xorl %eax, %eax .p2align 4,,9 ret .cfi_endproc .LFE0: .size foo, .-foo .section .rodata.cst8,"aM",@progbits,8 .align 8 .LC0: .quad xxxx .ident "GCC: (GNU) 4.7.0 20110720 (experimental)" .section .note.GNU-stack,"",@progbits [hjl@gnu-6 gcc]$