From bd8a2482569900a114d631f9c38353d3a96a1d85 Mon Sep 17 00:00:00 2001 From: Richard Sandiford Date: Tue, 3 Dec 2019 18:06:40 +0000 Subject: Don't install unnecessary ARRAY_REF element sizes Even EXACT_DIV_EXPR doesn't distribute across addition for wrapping types, so in general we can't fold EXACT_DIV_EXPRs of POLY_INT_CSTs at compile time. This was causing an ICE when trying to gimplify the element size field in an ARRAY_REF. If the result of that EXACT_DIV_EXPR is an invariant, we don't bother recording it in the ARRAY_REF and simply read the element size from the element type. This avoids the overhead of doing: /* ??? tree_ssa_useless_type_conversion will eliminate casts to sizetype from another type of the same width and signedness. */ if (TREE_TYPE (aligned_size) != sizetype) aligned_size = fold_convert_loc (loc, sizetype, aligned_size); return size_binop_loc (loc, MULT_EXPR, aligned_size, size_int (TYPE_ALIGN_UNIT (elmt_type))); each time array_ref_element_size is called. So rather than read array_ref_element_size, do some arithmetic on it, and only then check whether the result is an invariant, we might as well check whether the element size is an invariant to start with. We're then directly testing whether array_ref_element_size gives a reusable value. For consistency, the patch makes the same change for the offset field in a COMPONENT_REF, although I don't think that can trigger yet. 2019-12-03 Richard Sandiford gcc/ * gimplify.c (gimplify_compound_lval): Don't gimplify and install an array element size if array_element_size is already an invariant. Similarly don't gimplify and install a field offset if component_ref_field_offset is already an invariant. gcc/testsuite/ * gcc.target/aarch64/sve/acle/general-c/struct_1.c: New test. From-SVN: r278942 --- gcc/gimplify.c | 37 ++++++++++++++++++++----------------- 1 file changed, 20 insertions(+), 17 deletions(-) (limited to 'gcc/gimplify.c') diff --git a/gcc/gimplify.c b/gcc/gimplify.c index da65669..9073680 100644 --- a/gcc/gimplify.c +++ b/gcc/gimplify.c @@ -2987,17 +2987,18 @@ gimplify_compound_lval (tree *expr_p, gimple_seq *pre_p, gimple_seq *post_p, if (TREE_OPERAND (t, 3) == NULL_TREE) { - tree elmt_type = TREE_TYPE (TREE_TYPE (TREE_OPERAND (t, 0))); - tree elmt_size = unshare_expr (array_ref_element_size (t)); - tree factor = size_int (TYPE_ALIGN_UNIT (elmt_type)); - - /* Divide the element size by the alignment of the element - type (above). */ - elmt_size - = size_binop_loc (loc, EXACT_DIV_EXPR, elmt_size, factor); - + tree elmt_size = array_ref_element_size (t); if (!is_gimple_min_invariant (elmt_size)) { + elmt_size = unshare_expr (elmt_size); + tree elmt_type = TREE_TYPE (TREE_TYPE (TREE_OPERAND (t, 0))); + tree factor = size_int (TYPE_ALIGN_UNIT (elmt_type)); + + /* Divide the element size by the alignment of the element + type (above). */ + elmt_size = size_binop_loc (loc, EXACT_DIV_EXPR, + elmt_size, factor); + TREE_OPERAND (t, 3) = elmt_size; tret = gimplify_expr (&TREE_OPERAND (t, 3), pre_p, post_p, is_gimple_reg, @@ -3017,16 +3018,18 @@ gimplify_compound_lval (tree *expr_p, gimple_seq *pre_p, gimple_seq *post_p, /* Set the field offset into T and gimplify it. */ if (TREE_OPERAND (t, 2) == NULL_TREE) { - tree offset = unshare_expr (component_ref_field_offset (t)); - tree field = TREE_OPERAND (t, 1); - tree factor - = size_int (DECL_OFFSET_ALIGN (field) / BITS_PER_UNIT); - - /* Divide the offset by its alignment. */ - offset = size_binop_loc (loc, EXACT_DIV_EXPR, offset, factor); - + tree offset = component_ref_field_offset (t); if (!is_gimple_min_invariant (offset)) { + offset = unshare_expr (offset); + tree field = TREE_OPERAND (t, 1); + tree factor + = size_int (DECL_OFFSET_ALIGN (field) / BITS_PER_UNIT); + + /* Divide the offset by its alignment. */ + offset = size_binop_loc (loc, EXACT_DIV_EXPR, + offset, factor); + TREE_OPERAND (t, 2) = offset; tret = gimplify_expr (&TREE_OPERAND (t, 2), pre_p, post_p, is_gimple_reg, -- cgit v1.1