[Xen-ia64-devel] staging - gcc-4.1.x bug?

[Alex Williamson <alex.williamson@xxxxxx>]

   Any gcc wizards?  Compiling latest staging with gcc-4.1.x and
no_warns=y results in the errors below.  This doesn't happen with
gcc-3.4 or 4.2.  The warnings were introduced by this changeset:

http://xenbits.xensource.com/staging/xen-unstable.hg?rev/66fa2bc70e2a

The nested ternary operators in ns16550.c are where the problems occur,
but the code itself appears correct.  Is it time for me to give up on
gcc-4.1, or not worry about no_warns=y builds?  It can be fixed by
moving code around like this:

def_baud = console_has((index == 0) ? "com1" : "com2") ? BAUD_AUTO : 0;
uart->baud = defaults->baud ? : def_baud;

But that's a bit of a kludge and it still seems rather fragile.  Any
other ideas?  Thanks,

        Alex

-- 
Alex Williamson                             HP Open Source & Linux Org.


gcc -O2 -fomit-frame-pointer -DNDEBUG -fno-strict-aliasing -std=gnu99 -Wall 
-Wstrict-prototypes -Wno-unused-value -Wdeclaration-after-statement -nostdinc 
-fno-builtin -fno-common -mconstant-gp -O2 -fomit-frame-pointer -D__KERNEL__ 
-iwithprefix include -I/home/awilliam/xen/20070924-staging/xen/include 
-I/home/awilliam/xen/20070924-staging/xen/include/asm-ia64 
-I/home/awilliam/xen/20070924-staging/xen/include/asm-ia64/linux 
-I/home/awilliam/xen/20070924-staging/xen/include/asm-ia64/linux-xen 
-I/home/awilliam/xen/20070924-staging/xen/include/asm-ia64/linux-null 
-I/home/awilliam/xen/20070924-staging/xen/arch/ia64/linux 
-I/home/awilliam/xen/20070924-staging/xen/arch/ia64/linux-xen -DIA64 -DXEN 
-DLINUX_2_6 -ffixed-r13 -mfixed-range=f2-f5,f12-f127,b2-b5 -g 
-DCONFIG_XEN_IA64_EXPOSE_P2M -DCONFIG_XEN_IA64_PERVCPU_VHPT 
-DCONFIG_XEN_IA64_TLB_TRACK -DCONFIG_XEN_IA64_TLBFLUSH_CLOCK 
-Wa,--fatal-warnings -Werror -Wno-uninitialized -g -D__XEN__ -c ns16550.c -o 
ns16550.o
/tmp/cczn0I0R.s: Assembler messages:
/tmp/cczn0I0R.s:961: Warning: Use of 'addl' may violate WAW dependency 'GR%, % 
in 1 - 127' (impliedf), specific resource number is 34
/tmp/cczn0I0R.s:957: Warning: This is the location of the conflicting usage
/tmp/cczn0I0R.s:979: Warning: Use of 'ld8.mov' may violate RAW dependency 'GR%, 
% in 1 - 127' (impliedf), specific resource number is 34
/tmp/cczn0I0R.s:974: Warning: This is the location of the conflicting usage
/tmp/cczn0I0R.s:979: Warning: Use of 'ld8.mov' may violate WAW dependency 'GR%, 
% in 1 - 127' (impliedf), specific resource number is 34
/tmp/cczn0I0R.s:974: Warning: This is the location of the conflicting usage
/tmp/cczn0I0R.s:13741: Error: 6 warnings, treating warnings as errors
make[5]: *** [ns16550.o] Error 1
make[5]: Leaving directory 
`/home/awilliam/xen/20070924-staging/xen/drivers/char'
make[4]: *** [char/built_in.o] Error 2
make[4]: Leaving directory `/home/awilliam/xen/20070924-staging/xen/drivers'
make[3]: *** [/home/awilliam/xen/20070924-staging/xen/drivers/built_in.o] Error 
2
make[3]: Leaving directory `/home/awilliam/xen/20070924-staging/xen/arch/ia64'
make[2]: *** [/home/awilliam/xen/20070924-staging/xen/xen] Error 2
make[2]: Leaving directory `/home/awilliam/xen/20070924-staging/xen'
make[1]: *** [install] Error 2
make[1]: Leaving directory `/home/awilliam/xen/20070924-staging/xen'
make: *** [install-xen] Error 2



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