------- Comment #3 from tehila at il dot ibm dot com 2008-08-25 08:45 ------- (In reply to comment #2) > Andrew, thanks for your response and ideas. > From what we see, if -funroll-loops is on, the loops: > for (j = 0; j < 4; j++) > arr[j] = mat2[i][j]; > and > for (k = 0; k < 3; k++) > point += (double) mat1[arr[l]][k]; > are being unrolled by the early-unrolling (cunrolli pass, that Richard > Guenther > has added). > I think, the problem is that the loop > for (j = 0; j < 4; j++) > is not being unrolled.
The meaning here is to the second for (j = 0; j < 4; j++) loop. It's loop #4 in cunrolli pass. > cunrolli doesn't recognize # of iterations = 4. > I think it doesn't recognize it starts from 0. > Maybe Richard could help us understand why. > Hopefully, if that loop would be unrolled, the SRA will have the opportunity > to > do the transformation we expect it to do. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37221
