https://gcc.gnu.org/g:952725ad810600bf6b0730e3a121dca2fbd2c6ce
commit r17-2006-g952725ad810600bf6b0730e3a121dca2fbd2c6ce Author: Richard Biener <[email protected]> Date: Mon Jun 29 13:08:07 2026 +0200 Expand TMR fixup when we end up with a (void *)0 base When create_mem_ref falls back to a (void *)0 base address we currently only fall back to LEA plus indirection when the target can use a second index register. But we also need to do this if there's a scaled by one index. Or rather always to be safe. * tree-ssa-loop-ivopts.cc (rewrite_use_address): Always avoid TARGET_MEM_REF with a base of zero. * tree-ssa-sccvn.cc (vn_reference_maybe_forwprop_address): Do not forward TARGET_MEM_REF addresses. Diff: --- gcc/tree-ssa-loop-ivopts.cc | 3 +-- gcc/tree-ssa-sccvn.cc | 3 +++ 2 files changed, 4 insertions(+), 2 deletions(-) diff --git a/gcc/tree-ssa-loop-ivopts.cc b/gcc/tree-ssa-loop-ivopts.cc index 4ca553251887..f8dfc77de4ae 100644 --- a/gcc/tree-ssa-loop-ivopts.cc +++ b/gcc/tree-ssa-loop-ivopts.cc @@ -7639,11 +7639,10 @@ rewrite_use_address (struct ivopts_data *data, else { /* When we end up confused enough and have no suitable base but - stuffed everything to index2 use a LEA for the address and + stuffed everything to indexes use a LEA for the address and create a plain MEM_REF to avoid basing a memory reference on address zero which create_mem_ref_raw does as fallback. */ if (TREE_CODE (ref) == TARGET_MEM_REF - && TMR_INDEX2 (ref) != NULL_TREE && integer_zerop (TREE_OPERAND (ref, 0))) { ref = fold_build1 (ADDR_EXPR, TREE_TYPE (TREE_OPERAND (ref, 0)), ref); diff --git a/gcc/tree-ssa-sccvn.cc b/gcc/tree-ssa-sccvn.cc index 98b837be01d0..a95350abccbf 100644 --- a/gcc/tree-ssa-sccvn.cc +++ b/gcc/tree-ssa-sccvn.cc @@ -1507,6 +1507,9 @@ vn_reference_maybe_forwprop_address (vec<vn_reference_op_s> *ops, = wide_int_to_tree (TREE_TYPE (mem_op->op0), wi::to_poly_wide (new_mem_op->op0)); } + /* Do not forward addresses of TARGET_MEM_REF. */ + else if (tem[0].opcode == TARGET_MEM_REF) + return changed; else gcc_assert (tem.last ().opcode == STRING_CST); ops->pop ();
