From fb2f98bb6c5e016514bc3b93f8f1550e39e7d28f Mon Sep 17 00:00:00 2001 From: Richard Sandiford Date: Tue, 16 Jan 2018 15:13:32 +0000 Subject: [PATCH] Two fixes for live-out SLP inductions (PR 83857) vect_analyze_loop_operations was calling vectorizable_live_operation for all live-out phis, which led to a bogus ncopies calculation in the pure SLP case. I think v_a_l_o should only be passing phis that are vectorised using normal loop vectorisation, since vect_slp_analyze_node_operations handles the SLP side (and knows the correct slp_index and slp_node arguments to pass in, via vect_analyze_stmt). With that fixed we hit an older bug that vectorizable_live_operation didn't handle live-out SLP inductions. Fixed by using gimple_phi_result rather than gimple_get_lhs for phis. 2018-01-16 Richard Sandiford gcc/ PR tree-optimization/83857 * tree-vect-loop.c (vect_analyze_loop_operations): Don't call vectorizable_live_operation for pure SLP statements. (vectorizable_live_operation): Handle PHIs. gcc/testsuite/ PR tree-optimization/83857 * gcc.dg/vect/pr83857.c: New test. From-SVN: r256747 --- gcc/ChangeLog | 7 +++++++ gcc/testsuite/ChangeLog | 5 +++++ gcc/testsuite/gcc.dg/vect/pr83857.c | 30 ++++++++++++++++++++++++++++++ gcc/tree-vect-loop.c | 11 +++++++++-- 4 files changed, 51 insertions(+), 2 deletions(-) create mode 100644 gcc/testsuite/gcc.dg/vect/pr83857.c diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 055e924..979f5ae 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,10 @@ +2018-01-16 Richard Sandiford + + PR tree-optimization/83857 + * tree-vect-loop.c (vect_analyze_loop_operations): Don't call + vectorizable_live_operation for pure SLP statements. + (vectorizable_live_operation): Handle PHIs. + 2018-01-16 Richard Biener PR tree-optimization/83867 diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index ae57828..0e24ae4 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,8 @@ +2018-01-16 Richard Sandiford + + PR tree-optimization/83857 + * gcc.dg/vect/pr83857.c: New test. + 2018-01-16 Richard Biener PR tree-optimization/83867 diff --git a/gcc/testsuite/gcc.dg/vect/pr83857.c b/gcc/testsuite/gcc.dg/vect/pr83857.c new file mode 100644 index 0000000..92e648b --- /dev/null +++ b/gcc/testsuite/gcc.dg/vect/pr83857.c @@ -0,0 +1,30 @@ +/* { dg-do run } */ +/* { dg-additional-options "-ffast-math" } */ + +#define N 100 + +double __attribute__ ((noinline, noclone)) +f (double *x, double y) +{ + double a = 0; + for (int i = 0; i < N; ++i) + { + a += y; + x[i * 2] += a; + x[i * 2 + 1] += a; + } + return a - y; +} + +double x[N * 2]; + +int +main (void) +{ + if (f (x, 5) != (N - 1) * 5) + __builtin_abort (); + return 0; +} + +/* { dg-final { scan-tree-dump "Loop contains only SLP stmts" "vect" { target vect_double } } } */ +/* { dg-final { scan-tree-dump "vectorized 1 loops" "vect" { target vect_double } } } */ diff --git a/gcc/tree-vect-loop.c b/gcc/tree-vect-loop.c index 64b9ce3..79b8186 100644 --- a/gcc/tree-vect-loop.c +++ b/gcc/tree-vect-loop.c @@ -1851,7 +1851,10 @@ vect_analyze_loop_operations (loop_vec_info loop_vinfo) ok = vectorizable_reduction (phi, NULL, NULL, NULL, NULL); } - if (ok && STMT_VINFO_LIVE_P (stmt_info)) + /* SLP PHIs are tested by vect_slp_analyze_node_operations. */ + if (ok + && STMT_VINFO_LIVE_P (stmt_info) + && !PURE_SLP_STMT (stmt_info)) ok = vectorizable_live_operation (phi, NULL, NULL, -1, NULL); if (!ok) @@ -8217,7 +8220,11 @@ vectorizable_live_operation (gimple *stmt, gcc_assert (!LOOP_VINFO_FULLY_MASKED_P (loop_vinfo)); /* Get the correct slp vectorized stmt. */ - vec_lhs = gimple_get_lhs (SLP_TREE_VEC_STMTS (slp_node)[vec_entry]); + gimple *vec_stmt = SLP_TREE_VEC_STMTS (slp_node)[vec_entry]; + if (gphi *phi = dyn_cast (vec_stmt)) + vec_lhs = gimple_phi_result (phi); + else + vec_lhs = gimple_get_lhs (vec_stmt); /* Get entry to use. */ bitstart = bitsize_int (vec_index); -- 2.7.4