Hi, when I compile "Hello World" optimized, I get error messages and an unusable binary. Everything works fine with gcc version 3.3.5 (or unoptimized). Cheers Christian maeder@leo -> uname -a SunOS leo 5.8 Generic_117000-05 sun4u sparc SUNW,Sun-Fire-280R maeder@leo -> ghc --version The Glorious Glasgow Haskell Compilation System, version 6.2.1 maeder@leo -> gcc -v Reading specs from /export/software/mirror/sparc-solaris/lang/bin/../lib/gcc/sparc-sun-solaris2.8/3.4.3/specs Configured with: ../gcc-3.4.3/configure --prefix=/usr/local/lang -program-suffix=_3.4.3 --with-as=/usr/ccs/bin/as --with-ld=/usr/ccs/bin/ld --enable-version-specific-runtime-libs --enable-languages=c,c++,f77 --enable-shared=libstdc++ --disable-nls Thread model: posix gcc version 3.4.3 maeder@leo -> ghc --make Main.hs -O Chasing modules from: Main.hs Compiling Main ( Main.hs, Main.o ) /tmp/ghc14393.hc: In function `__stginit_Main': /tmp/ghc14393.hc:5: note: if this code is reached, the program will abort /tmp/ghc14393.hc: In function `__stginit_ZCMain': /tmp/ghc14393.hc:12: note: if this code is reached, the program will abort /tmp/ghc14393.hc: In function `Main_a_entry': /tmp/ghc14393.hc:33: note: if this code is reached, the program will abort /tmp/ghc14393.hc: In function `Main_main_slow': /tmp/ghc14393.hc:49: note: if this code is reached, the program will abort /tmp/ghc14393.hc: In function `Main_main_entry': /tmp/ghc14393.hc:64: note: if this code is reached, the program will abort /tmp/ghc14393.hc: In function `ZCMain_main_slow': /tmp/ghc14393.hc:79: note: if this code is reached, the program will abort Linking ... maeder@leo -> ./a.out Illegal Instruction