From 32b5875c911f80d551d006d7473e6f1f8705857a Mon Sep 17 00:00:00 2001 From: Jakub Jelinek Date: Sat, 18 Feb 2023 12:40:49 +0100 Subject: [PATCH] reassoc: Fold some statements [PR108819] This spot in update_ops can replace one or both of the assign operands with constants, creating 1 & 1 and similar expressions which can confuse later passes until they are folded. Rather than folding both constants by hand and also handling swapping of operands for commutative ops if the first one is constant and second one is not, the following patch just uses fold_stmt_inplace to do that. I think we shouldn't fold more than the single statement because that could screw up the rest of the pass, we'd have to mark all those with uids, visited and the like. 2023-02-18 Jakub Jelinek PR tree-optimization/108819 * tree-ssa-reassoc.cc (update_ops): Fold new stmt in place. * gcc.dg/pr108819.c: New test. --- gcc/testsuite/gcc.dg/pr108819.c | 19 +++++++++++++++++++ gcc/tree-ssa-reassoc.cc | 3 +++ 2 files changed, 22 insertions(+) create mode 100644 gcc/testsuite/gcc.dg/pr108819.c diff --git a/gcc/testsuite/gcc.dg/pr108819.c b/gcc/testsuite/gcc.dg/pr108819.c new file mode 100644 index 00000000000..28fa558b260 --- /dev/null +++ b/gcc/testsuite/gcc.dg/pr108819.c @@ -0,0 +1,19 @@ +/* PR tree-optimization/108819 */ +/* { dg-do compile } */ +/* { dg-options "-O1 -fno-tree-ccp -fno-tree-forwprop" } */ + +int a, b; + +int +main () +{ + int d = 1; + for (; b; b++) + if (a < 1) + while (d <= a && a <= 0UL) + { + int *e = &d; + *e = 0; + } + return 0; +} diff --git a/gcc/tree-ssa-reassoc.cc b/gcc/tree-ssa-reassoc.cc index f163612f140..8fd22591f55 100644 --- a/gcc/tree-ssa-reassoc.cc +++ b/gcc/tree-ssa-reassoc.cc @@ -4687,6 +4687,9 @@ update_ops (tree var, enum tree_code code, const vec &ops, gimple_set_uid (g, gimple_uid (stmt)); gimple_set_visited (g, true); gsi_insert_before (&gsi, g, GSI_SAME_STMT); + gimple_stmt_iterator gsi2 = gsi_for_stmt (g); + if (fold_stmt_inplace (&gsi2)) + update_stmt (g); } return var; }