From: Richard Sandiford Date: Tue, 3 Dec 2019 18:06:40 +0000 (+0000) Subject: Don't install unnecessary ARRAY_REF element sizes X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=bd8a2482569900a114d631f9c38353d3a96a1d85;p=gcc.git 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 --- diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 1b246171d46..430aedbcb05 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,10 @@ +2019-12-03 Richard Sandiford + + * 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. + 2019-12-03 Richard Sandiford * cfgexpand.c (discover_nonconstant_array_refs_r): If an access diff --git a/gcc/gimplify.c b/gcc/gimplify.c index da6566903e0..9073680cb31 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, diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index 028755bb51a..39e8ace59f7 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,7 @@ +2019-12-03 Richard Sandiford + + * gcc.target/aarch64/sve/acle/general-c/struct_1.c: New test. + 2019-12-03 Richard Sandiford * gcc.target/aarch64/sve/acle/general/deref_1.c: New test. diff --git a/gcc/testsuite/gcc.target/aarch64/sve/acle/general-c/struct_1.c b/gcc/testsuite/gcc.target/aarch64/sve/acle/general-c/struct_1.c new file mode 100644 index 00000000000..1ebc229250e --- /dev/null +++ b/gcc/testsuite/gcc.target/aarch64/sve/acle/general-c/struct_1.c @@ -0,0 +1,10 @@ +/* { dg-options "-std=c99" } */ + +#include + +void +f (svint8_t a, svint8_t b) +{ + /* Not supported, but mustn't ICE. */ + (svint8x2_t) { a, b }; +}