------- Comment #2 from dominiq at lps dot ens dot fr 2008-12-06 23:56 ------- The output of -ftree-vectorizer-verbose=6 gives:
/opt/gcc/_gcc_clean/gcc/testsuite/gcc.dg/vect/vect-67.c:30: note: not vectorized: too many BBs in loop. /opt/gcc/_gcc_clean/gcc/testsuite/gcc.dg/vect/vect-67.c:17: note: Detected interleaving ia[i_91][1][8] and ia[i_91][1][9] /opt/gcc/_gcc_clean/gcc/testsuite/gcc.dg/vect/vect-67.c:17: note: Detected interleaving ia[i_91][1][8] and ia[i_91][1][10] /opt/gcc/_gcc_clean/gcc/testsuite/gcc.dg/vect/vect-67.c:17: note: Detected interleaving ia[i_91][1][8] and ia[i_91][1][11] /opt/gcc/_gcc_clean/gcc/testsuite/gcc.dg/vect/vect-67.c:17: note: Detected interleaving ia[i_91][1][8] and ia[i_91][1][12] ... /opt/gcc/_gcc_clean/gcc/testsuite/gcc.dg/vect/vect-67.c:17: note: Detected interleaving ia[i_91][1][20] and ia[i_91][1][21] /opt/gcc/_gcc_clean/gcc/testsuite/gcc.dg/vect/vect-67.c:17: note: Detected interleaving ia[i_91][1][20] and ia[i_91][1][22] /opt/gcc/_gcc_clean/gcc/testsuite/gcc.dg/vect/vect-67.c:17: note: Detected interleaving ia[i_91][1][20] and ia[i_91][1][23] /opt/gcc/_gcc_clean/gcc/testsuite/gcc.dg/vect/vect-67.c:17: note: Detected interleaving ia[i_91][1][21] and ia[i_91][1][22] /opt/gcc/_gcc_clean/gcc/testsuite/gcc.dg/vect/vect-67.c:17: note: Detected interleaving ia[i_91][1][21] and ia[i_91][1][23] /opt/gcc/_gcc_clean/gcc/testsuite/gcc.dg/vect/vect-67.c:17: note: Detected interleaving ia[i_91][1][22] and ia[i_91][1][23] /opt/gcc/_gcc_clean/gcc/testsuite/gcc.dg/vect/vect-67.c:17: note: not vectorized: complicated access pattern. /opt/gcc/_gcc_clean/gcc/testsuite/gcc.dg/vect/vect-67.c:9: note: vectorized 0 loops in function. The failure appeared between revisions 137614 (passed) and 137631, most of them are branches or FE patches but 137620 (IPA->unlikely?) and 137631. Compiling with -fno-tree-pre does not help. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37853
