From 1a7200da71550e6f92da66f0b328bb20d3bcdf35 Mon Sep 17 00:00:00 2001 From: Richard Biener Date: Tue, 19 Jul 2022 09:57:22 +0200 Subject: [PATCH] middle-end/106331 - fix mem attributes for string op arguments get_memory_rtx tries hard to come up with a MEM_EXPR to record in the memory attributes but in the last fallback fails to properly account for an unknown offset and thus, as visible in this testcase, incorrect alignment computed from set_mem_attributes. The following rectifies both parts. PR middle-end/106331 * builtins.cc (get_memory_rtx): Compute alignment from the original address and set MEM_OFFSET to unknown when we create a MEM_EXPR from the base object of the address. * gfortran.dg/pr106331.f90: New testcase. (cherry picked from commit e4ff11a8f2e80adb8ada69bf35ee6a1ab18a9c85) --- gcc/builtins.cc | 13 +++++++++---- gcc/testsuite/gfortran.dg/pr106331.f90 | 7 +++++++ 2 files changed, 16 insertions(+), 4 deletions(-) create mode 100644 gcc/testsuite/gfortran.dg/pr106331.f90 diff --git a/gcc/builtins.cc b/gcc/builtins.cc index 85459200a09b..57929a42bc4c 100644 --- a/gcc/builtins.cc +++ b/gcc/builtins.cc @@ -1360,7 +1360,7 @@ expand_builtin_prefetch (tree exp) rtx get_memory_rtx (tree exp, tree len) { - tree orig_exp = exp; + tree orig_exp = exp, base; rtx addr, mem; /* When EXP is not resolved SAVE_EXPR, MEM_ATTRS can be still derived @@ -1391,10 +1391,11 @@ get_memory_rtx (tree exp, tree len) if (is_gimple_mem_ref_addr (TREE_OPERAND (exp, 0))) set_mem_attributes (mem, exp, 0); else if (TREE_CODE (TREE_OPERAND (exp, 0)) == ADDR_EXPR - && (exp = get_base_address (TREE_OPERAND (TREE_OPERAND (exp, 0), - 0)))) + && (base = get_base_address (TREE_OPERAND (TREE_OPERAND (exp, 0), + 0)))) { - exp = build_fold_addr_expr (exp); + unsigned int align = get_pointer_alignment (TREE_OPERAND (exp, 0)); + exp = build_fold_addr_expr (base); exp = fold_build2 (MEM_REF, build_array_type (char_type_node, build_range_type (sizetype, @@ -1402,6 +1403,10 @@ get_memory_rtx (tree exp, tree len) NULL)), exp, build_int_cst (ptr_type_node, 0)); set_mem_attributes (mem, exp, 0); + /* Since we stripped parts make sure the offset is unknown and the + alignment is computed from the original address. */ + clear_mem_offset (mem); + set_mem_align (mem, align); } set_mem_alias_set (mem, 0); return mem; diff --git a/gcc/testsuite/gfortran.dg/pr106331.f90 b/gcc/testsuite/gfortran.dg/pr106331.f90 new file mode 100644 index 000000000000..3873863be481 --- /dev/null +++ b/gcc/testsuite/gfortran.dg/pr106331.f90 @@ -0,0 +1,7 @@ +! { dg-do run } +! { dg-options "-Og" } + +PROGRAM main + CHARACTER(LEN=24) :: a(2) + a = '' +END PROGRAM -- 2.47.3