When we swap operands for SLP builds we lose track where exactly pattern defs are - but we fail to update the any_pattern member of the operands info. Do so conservatively.
Bootstrapped and tested on x86_64-unknown-linux-gnu, pushed. 2021-08-25 Richard Biener <rguent...@suse.de> PR tree-optimization/102046 * tree-vect-slp.c (vect_build_slp_tree_2): Conservatively update ->any_pattern when swapping operands. * gcc.dg/vect/pr102046.c: New testcase. --- gcc/testsuite/gcc.dg/vect/pr102046.c | 19 +++++++++++++++++++ gcc/tree-vect-slp.c | 4 ++++ 2 files changed, 23 insertions(+) create mode 100644 gcc/testsuite/gcc.dg/vect/pr102046.c diff --git a/gcc/testsuite/gcc.dg/vect/pr102046.c b/gcc/testsuite/gcc.dg/vect/pr102046.c new file mode 100644 index 00000000000..ae48b497dc0 --- /dev/null +++ b/gcc/testsuite/gcc.dg/vect/pr102046.c @@ -0,0 +1,19 @@ +/* { dg-do compile } */ +/* { dg-additional-options "-O3 -fvect-cost-model=dynamic" } */ +/* { dg-additional-options "-march=btver2" { target x86_64-*-* i?86-*-* } } */ + +struct S +{ + unsigned a, b; +}; + +struct S g; + +void +foo (struct S *o) +{ + struct S s = g; + s.b *= 3; + s.a -= s.a / 2; + *o = s; +} diff --git a/gcc/tree-vect-slp.c b/gcc/tree-vect-slp.c index edc11c62793..4d688c7a267 100644 --- a/gcc/tree-vect-slp.c +++ b/gcc/tree-vect-slp.c @@ -2311,6 +2311,10 @@ out: } if (dump_enabled_p ()) dump_printf (MSG_NOTE, "\n"); + /* After swapping some operands we lost track whether an + operand has any pattern defs so be conservative here. */ + if (oprnds_info[0]->any_pattern || oprnds_info[1]->any_pattern) + oprnds_info[0]->any_pattern = oprnds_info[1]->any_pattern = true; /* And try again with scratch 'matches' ... */ bool *tem = XALLOCAVEC (bool, group_size); if ((child = vect_build_slp_tree (vinfo, oprnd_info->def_stmts, -- 2.31.1