http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47754
--- Comment #3 from Matthias Kretz <kretz at kde dot org> 2011-02-15 16:40:38 UTC --- ICC??? Whatever, I stopped to trust that compiler long ago: <unaligned()>: vmovups 0x2039b8(%rip),%xmm0 vmovups 0x2039b4(%rip),%xmm1 vinsertf128 $0x1,0x2039b6(%rip),%ymm0,%ymm2 vinsertf128 $0x1,0x2039b0(%rip),%ymm1,%ymm3 vaddps %ymm3,%ymm2,%ymm4 vmovups %ymm4,0x20399c(%rip) vzeroupper retq <aligned()>: vmovups 0x203978(%rip),%ymm0 vaddps 0x203974(%rip),%ymm0,%ymm1 vmovups %ymm1,0x203974(%rip) vzeroupper retq Nice optimization of unaligned loads there... not. ??? Just a small side-note for your enjoyment: I wrote a C++ abstraction for SSE; and with GCC this gives an almost four-fold speedup for Mandelbrot. ICC on the other hand compiles such awful code that - even with SSE use - it rather creates a four-fold slowdown compared to the non-SSE code. GCC really is a nice compiler! Keep on rocking!
