Benchmark test 416.gamess from SPEC CPU2006 takes a very long time to compile with current trunk on powerpc64-linux (both -m32 and -m64) with "-O2 -floop-interchange". The slowdown started between r157243 on 20100305 and r157293 on 20100308. Here's a minimized testcase that takes several minutes now, but much less than a second before the slowdown:
SUBROUTINE BUG(A,B,X,Y,Z,N) IMPLICIT NONE DOUBLE PRECISION A(*),B(*),X(*),Y(*),Z(*) INTEGER N,J,K K = 0 DO J = 1,N K = K+1 X(K) = B(J+N*7) Y(K) = B(J+N*8) Z(K) = B(J+N*2) + A(J+N*2) K = K+1 X(K) = B(J+N*3) + A(J+N*3) Y(K) = B(J+N*9) + A(J) Z(K) = B(J+N*15) K = K+1 X(K) = B(J+N*4) + A(J+N*4) Y(K) = B(J+N*15) Z(K) = B(J+N*10) + A(J) K = K+1 X(K) = B(J+N*11) + A(J+N) Y(K) = B(J+N*5) + A(J+N*5) Z(K) = B(J+N*16) K = K+1 X(K) = B(J+N*16) Y(K) = B(J+N*6) + A(J+N*6) Z(K) = B(J+N*12) + A(J+N) K = K+1 X(K) = B(J+N*13) + A(J+N*2) Y(K) = B(J+N*17) Z(K) = B(J+N*7) + A(J+N*7) ENDDO RETURN END -- Summary: very long compile time for gamess with -floop- interchange Product: gcc Version: 4.5.0 Status: UNCONFIRMED Keywords: compile-time-hog Severity: normal Priority: P3 Component: tree-optimization AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: janis at gcc dot gnu dot org GCC target triplet: powerpc64-linux http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43349