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| author | Richard Biener <rguenther@suse.de> | 2022-11-08 13:49:16 +0100 |
|---|---|---|
| committer | Richard Biener <rguenther@suse.de> | 2022-11-08 16:38:39 +0100 |
| commit | 7899582a059a9d8c25bfff305cd236d219dc4f20 (patch) | |
| tree | f528ce0356c7f144bacf2cb8d6aebb5292cc8fc7 /gcc/gimple-low.cc | |
| parent | 215355d302d8602c7eeefb9c927a3dbb221714c8 (diff) | |
| download | gcc-7899582a059a9d8c25bfff305cd236d219dc4f20.zip gcc-7899582a059a9d8c25bfff305cd236d219dc4f20.tar.gz gcc-7899582a059a9d8c25bfff305cd236d219dc4f20.tar.bz2 | |
tree-optimization/107389 - honor __builtin_assume_alignment at -O0
The following makes sure to set alignment information on the LHS
of __builtin_assume_alignment calls even when not optimizing so
uses as arguments to builtin functions like memcpy or __atomic_load_n
can be reflected at RTL expansion time.
PR tree-optimization/107389
* gimple-low.cc (lower_builtin_assume_aligned): New.
(lower_stmt): Call it.
* gcc.dg/pr107389.c: New testcase.
Diffstat (limited to 'gcc/gimple-low.cc')
| -rw-r--r-- | gcc/gimple-low.cc | 41 |
1 files changed, 41 insertions, 0 deletions
diff --git a/gcc/gimple-low.cc b/gcc/gimple-low.cc index 512aa9f..53df2e7 100644 --- a/gcc/gimple-low.cc +++ b/gcc/gimple-low.cc @@ -84,6 +84,7 @@ static void lower_try_catch (gimple_stmt_iterator *, struct lower_data *); static void lower_gimple_return (gimple_stmt_iterator *, struct lower_data *); static void lower_builtin_setjmp (gimple_stmt_iterator *); static void lower_builtin_posix_memalign (gimple_stmt_iterator *); +static void lower_builtin_assume_aligned (gimple_stmt_iterator *); /* Lower the body of current_function_decl from High GIMPLE into Low @@ -768,6 +769,14 @@ lower_stmt (gimple_stmt_iterator *gsi, struct lower_data *data) lower_builtin_posix_memalign (gsi); return; } + else if (DECL_FUNCTION_CODE (decl) == BUILT_IN_ASSUME_ALIGNED + && !optimize) + { + lower_builtin_assume_aligned (gsi); + data->cannot_fallthru = false; + gsi_next (gsi); + return; + } } if (decl && (flags_from_decl_or_type (decl) & ECF_NORETURN)) @@ -1310,6 +1319,38 @@ lower_builtin_posix_memalign (gimple_stmt_iterator *gsi) gsi_insert_after (gsi, stmt, GSI_NEW_STMT); gsi_insert_after (gsi, gimple_build_label (noalign_label), GSI_NEW_STMT); } + +/* Lower calls to __builtin_assume_aligned when not optimizing. */ + +static void +lower_builtin_assume_aligned (gimple_stmt_iterator *gsi) +{ + gcall *call = as_a <gcall *> (gsi_stmt (*gsi)); + + tree lhs = gimple_call_lhs (call); + if (!lhs || !POINTER_TYPE_P (TREE_TYPE (lhs)) || TREE_CODE (lhs) != SSA_NAME) + return; + + tree align = gimple_call_arg (call, 1); + tree misalign = (gimple_call_num_args (call) > 2 + ? gimple_call_arg (call, 2) : NULL_TREE); + if (!tree_fits_uhwi_p (align) + || (misalign && !tree_fits_uhwi_p (misalign))) + return; + + unsigned aligni = TREE_INT_CST_LOW (align); + unsigned misaligni = misalign ? TREE_INT_CST_LOW (misalign) : 0; + if (aligni <= 1 + || (aligni & (aligni - 1)) != 0 + || (misaligni & ~(aligni - 1)) != 0) + return; + + /* For lowering we simply transfer alignment information to the + result and leave the call otherwise unchanged, it will be elided + at RTL expansion time. */ + ptr_info_def *pi = get_ptr_info (lhs); + set_ptr_info_alignment (pi, aligni, misaligni); +} /* Record the variables in VARS into function FN. */ |