Hi, I posted a reply to http://gcc.gnu.org/ml/gcc-help/2006-03/msg00159.html but seeing as it was in March it's probably disappeared under the radar. I'm running gcc 4: $: /export/BobTheBuilder/compilers/x86-linux-cross/x86_64-linux-gcc-4.1.0/bin/x86_64-linux-gcc --version x86_64-linux-gcc (GCC) 4.1.0 And I'm seeing problems with signalling NaN propagation in my code if I compile with -O3. The problem is is the compiler is putting the operands into the x87 registers with code like: flds 0x108(%rsp) fstps 0x20(%rsp) Which kills the Signalling aspect of the NaN so when it gets to my hand crafted SSE2 assembler routine the signal isn't thrown. I'm compiling the code with: -march=nocona -mfpmath=sse -msse2 -ffast-math But it doesn't seem to make any difference. Putting a fprintf to dump the operands before the call does change the register allocation and keep the numbers un-molested in xmm registers. However I'm under the impression gcc shouldn't be generating any x87 code unless explicitly enabled. I also tried: -ffixed-st0 -ffixed-st1 -ffixed-st2 -ffixed-st3 -ffixed-st4 -ffixed-st5 -ffixed-st6 -ffixed-st7 To try and force the x87 floating point registers from being used. Unfortunately gcc didn't recognise the registers and I couldn't find the REGISTER_NAMES macro definition in the sources for what the correct incantation was. The previously mentioned message seemed to imply this was fixed but I can't find any reference in the 4.1.1 ChangeLog. Any suggestions on how I can work around this bug? -- Alex, homepage: http://www.bennee.com/~alex/ The qotc (quote of the con) was Liz's: "My brain is paged out to my liver"
