------- Comment #8 from jv244 at cam dot ac dot uk 2008-08-19 05:43 ------- (In reply to comment #7) > That is, GCCs inner loop is > > .L6: > addl $1, %eax > addsd %xmm12, %xmm11 > cmpl $100000000, %eax > addsd %xmm14, %xmm3 > addsd %xmm15, %xmm2 > addsd %xmm13, %xmm1 > jne .L6 > > which doesn't necessarily look slower than ICCs. >
Right... checked trunk, and it now does something very smart with the testcase from comment 4 ... it is now about 10 times faster than ifort (9.1 /11.0) > gfortran -O3 -ftree-vectorize -ffast-math -march=native -S PR31079_4.f90 > ./a.out 0.25201499 > ifort -xT -O2 PR31079_4.f90 > ./a.out 2.040127 I'll see if there is a way to get the testcase somewhat smarter. I checked the very first program (comment #0), and this is still slower with gfortran (intel 3.51 vs gfortran 4.1). Just for completeness, I attach the Fortran source and the intel assembly. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31079
