From af0d2d95a5f767d92bd64f959679fb4612247b0b Mon Sep 17 00:00:00 2001 From: Richard Biener Date: Wed, 21 Aug 2024 13:56:40 +0200 Subject: [PATCH] tree-optimization/116380 - bogus SSA update with loop distribution When updating LC PHIs after copying loops we have to handle defs defined outside of the loop appropriately (by not setting them to NULL ...). This mimics how we handle this in the SSA updating code of the vectorizer. PR tree-optimization/116380 * tree-loop-distribution.cc (copy_loop_before): Handle out-of-loop defs appropriately. * gcc.dg/torture/pr116380.c: New testcase. --- gcc/testsuite/gcc.dg/torture/pr116380.c | 16 ++++++++++++++++ gcc/tree-loop-distribution.cc | 3 +++ 2 files changed, 19 insertions(+) create mode 100644 gcc/testsuite/gcc.dg/torture/pr116380.c diff --git a/gcc/testsuite/gcc.dg/torture/pr116380.c b/gcc/testsuite/gcc.dg/torture/pr116380.c new file mode 100644 index 000000000000..5ffd99459d26 --- /dev/null +++ b/gcc/testsuite/gcc.dg/torture/pr116380.c @@ -0,0 +1,16 @@ +/* { dg-do compile } */ +/* { dg-additional-options "-fno-tree-scev-cprop" } */ + +int a[3], d[3], c; +int f(int e, int b) +{ + for (; e < 3; e++) + { + a[0] = 0; + if (b) + c = b; + d[e] = 0; + a[e] = 0; + } + return e; +} diff --git a/gcc/tree-loop-distribution.cc b/gcc/tree-loop-distribution.cc index f87393ee94d6..10f261a8769b 100644 --- a/gcc/tree-loop-distribution.cc +++ b/gcc/tree-loop-distribution.cc @@ -980,6 +980,9 @@ copy_loop_before (class loop *loop, bool redirect_lc_phi_defs) if (TREE_CODE (USE_FROM_PTR (use_p)) == SSA_NAME) { tree new_def = get_current_def (USE_FROM_PTR (use_p)); + if (!new_def) + /* Something defined outside of the loop. */ + continue; SET_USE (use_p, new_def); } } -- 2.47.3