From 2686de5617bfb572343933be2883e8274c9735b5 Mon Sep 17 00:00:00 2001 From: Richard Biener Date: Mon, 9 Nov 2020 15:19:56 +0100 Subject: [PATCH] tree-optimization/97760 - reduction paths with unhandled live stmt This makes sure we reject reduction paths with a live stmt that is not the last one altering the value. This is because we do not handle this in the epilogue unless there's a scalar epilogue loop. 2020-11-09 Richard Biener PR tree-optimization/97760 * tree-vect-loop.c (check_reduction_path): Reject reduction paths we do not handle in epilogue generation. * gcc.dg/vect/pr97760.c: New testcase. --- gcc/testsuite/gcc.dg/vect/pr97760.c | 26 ++++++++++++++++++++++++++ gcc/tree-vect-loop.c | 9 ++++++--- 2 files changed, 32 insertions(+), 3 deletions(-) create mode 100644 gcc/testsuite/gcc.dg/vect/pr97760.c diff --git a/gcc/testsuite/gcc.dg/vect/pr97760.c b/gcc/testsuite/gcc.dg/vect/pr97760.c new file mode 100644 index 00000000000..da5ac937a43 --- /dev/null +++ b/gcc/testsuite/gcc.dg/vect/pr97760.c @@ -0,0 +1,26 @@ +#include "tree-vect.h" + +int b=1; +static int *g = &b; + +void __attribute__((noipa)) +h (unsigned int n) +{ + int i = 3; + int f = 3; + for (; f <= 50; f += 4) { + i += 4; + *g = i; + i += n; + } +} + +int main () +{ + check_vect (); + + h (9); + if (*g != 150 || b != 150) + __builtin_abort (); + return 0; +} diff --git a/gcc/tree-vect-loop.c b/gcc/tree-vect-loop.c index 977633a3ce3..39b7319e825 100644 --- a/gcc/tree-vect-loop.c +++ b/gcc/tree-vect-loop.c @@ -3326,14 +3326,17 @@ pop: fail = true; break; } - /* Check there's only a single stmt the op is used on inside - of the loop. */ + /* Check there's only a single stmt the op is used on. For the + not value-changing tail and the last stmt allow out-of-loop uses. + ??? We could relax this and handle arbitrary live stmts by + forcing a scalar epilogue for example. */ imm_use_iterator imm_iter; gimple *op_use_stmt; unsigned cnt = 0; FOR_EACH_IMM_USE_STMT (op_use_stmt, imm_iter, op) if (!is_gimple_debug (op_use_stmt) - && flow_bb_inside_loop_p (loop, gimple_bb (op_use_stmt))) + && (*code != ERROR_MARK + || flow_bb_inside_loop_p (loop, gimple_bb (op_use_stmt)))) { /* We want to allow x + x but not x < 1 ? x : 2. */ if (is_gimple_assign (op_use_stmt) -- 2.30.2