gcc.3.4.6 vs. gcc-4.3.2 re: pseudo instructions & bus error

["SHANE MILLER, BLOOMBERG/ 731 LEXIN" <smiller53 at bloomberg dot net>]

Hi, I compile .c files using both gcc.3.4.6 and gcc-4.3.2 chaining to Sun's 
assembler "Sun Compiler Common 10 Patch 09/04/2007" in both cases:

  gcc -O3 -D_SOLARIS -D_SPARC -Wall -Wa,-xarch=v8plus -fexceptions -c ...

I run on a "SunOS 5.10 Generic_137111-08 sun4v sparc SUNW,T5240" box with 
16x1582MHz (UltraSPARC-T2+) procesors. The gcc.3.4.6 build works. The gcc-4.3.2 
cores with a BUS error. 

How can I turn pseudo assembler instructions off and/or what switch can I add 
to the gcc line to make this BUS error go away? Either the assembler is wrong 
and/or gcc aligned a variable on the wrong boundary. Details follow.

==========
The key difference appears to be that 3.4.6 does not emit pseudo instructions 
which work on extended 8-byte words. 4.3.2 does. In this case 4.3.2 emits stx 
which is output as clrx i.e. appears in objdump of the .o file. That particular 
code fragment is the assembler equivalent of "tm->counter = 0" except counter 
is on a 4-byte boundary hence bus error:

    .align 4
    .global init
    .type   init, #function
    .proc   012
init:
.LLFB4:
    save    %sp, -112, %sp
.LLCFI9:
    st  %g0, [%i0+28]
    st  %g0, [%i0+32]
    mov -1, %g1
    st  %g0, [%i0+36]
    stx %g0, [%i0+56]                  <-  BUS ERROR HERE. 8 byte operation
    mov %i1, %o0                           on memory on a non-8 byte boundary
    st  %g0, [%i0+40]
    add %i0, 44, %o1
    call    init_helper, 0
     st %g1, [%i0+48]
    cmp %o0, 0
    bne,pt  %icc, .LL112
     sethi  %hi(369664), %o0
    call    stop, 0
     or %o0, 399, %o0
.LL112:
    return  %i7+8

Contrast with the 3.4.6 output:

    .align 4
    .global init
    .type   init, #function
    .proc   012
init:
.LLFB4:
    !#PROLOGUE# 0
    save    %sp, -112, %sp
.LLCFI0:
    !#PROLOGUE# 1
    st  %g0, [%i0+28]
    st  %g0, [%i0+32]
    st  %g0, [%i0+36]
    mov 0, %o4                         <- no stx: this works
    mov 0, %o5
    mov -1, %g1
    std %o4, [%i0+56]
    st  %g1, [%i0+48]
    add %i0, 44, %o1
    st  %g0, [%i0+40]
    call    init_helper, 0
    mov %i1, %o0
    cmp %o0, 0
    sethi   %hi(369664), %o0
    bne .LL4
    or  %o0, 399, %o0
    call    stop, 0
     nop
.LL4:
    ret