Hi, https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87306, it's older POWER hardware specific test case issue. On POWER7 and earlier, we implicitly set flag -mno-allow-movmisalign which disables vectorization when to vectorize the code requires that misaligned loads and stores. For POWER8 and upper, the opposite value is implicitly set(-mallow-movmisalign), then the vectorization performs as expected.
Similar to https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65484, the proposed fix is to make dg-final checks whether vect_hw_misalign support on powerpc, only further verify the dump pattern when it's on to consitent to the behavior. Tested on trunk for POWER8 LE and POWER7 BE systems. Is this ok for trunk? --- gcc/testsuite/ChangeLog 2019-01-16 Kewen Lin <li...@gcc.gnu.org> PR target/87306 * gcc.dg/vect/bb-slp-pow-1.c : Modify to reflect that the loop is not vectorized on POWER unless hardware misaligned loads are available. diff --git a/gcc/testsuite/gcc.dg/vect/bb-slp-pow-1.c b/gcc/testsuite/gcc.dg/vect/bb-slp-pow-1.c index 5a05bd4..6742e12 100644 --- a/gcc/testsuite/gcc.dg/vect/bb-slp-pow-1.c +++ b/gcc/testsuite/gcc.dg/vect/bb-slp-pow-1.c @@ -25,4 +25,8 @@ main (void) return 0; } -/* { dg-final { scan-tree-dump-times "basic block vectorized" 1 "slp2" } } */ +/* On older powerpc hardware (POWER7 and earlier), the default flag + -mno-allow-movmisalign prevents vectorization. On POWER8 and later, + when vect_hw_misalign is true, vectorization occurs. */ + +/* { dg-final { scan-tree-dump-times "basic block vectorized" 1 "slp2" { target {{ ! powerpc*-*-* } || { powerpc*-*-* && vect_hw_misalign }} } } } */
