diff options
Diffstat (limited to 'gcc/expr.c')
| -rw-r--r-- | gcc/expr.c | 37 |
1 files changed, 26 insertions, 11 deletions
@@ -3788,7 +3788,7 @@ expand_assignment (tree to, tree from) push_temp_slots (); tem = get_inner_reference (to, &bitsize, &bitpos, &offset, &mode1, - &unsignedp, &volatilep); + &unsignedp, &volatilep, true); /* If we are going to use store_bit_field and extract_bit_field, make sure to_rtx will be safe for multiple use. */ @@ -5244,13 +5244,27 @@ store_field (rtx target, HOST_WIDE_INT bitsize, HOST_WIDE_INT bitpos, If the field describes a variable-sized object, *PMODE is set to VOIDmode and *PBITSIZE is set to -1. An access cannot be made in - this case, but the address of the object can be found. */ + this case, but the address of the object can be found. + + If KEEP_ALIGNING is true and the target is STRICT_ALIGNMENT, we don't + look through nodes that serve as markers of a greater alignment than + the one that can be deduced from the expression. These nodes make it + possible for front-ends to prevent temporaries from being created by + the middle-end on alignment considerations. For that purpose, the + normal operating mode at high-level is to always pass FALSE so that + the ultimate containing object is really returned; moreover, the + associated predicate handled_component_p will always return TRUE + on these nodes, thus indicating that they are essentially handled + by get_inner_reference. TRUE should only be passed when the caller + is scanning the expression in order to build another representation + and specifically knows how to handle these nodes; as such, this is + the normal operating mode in the RTL expanders. */ tree get_inner_reference (tree exp, HOST_WIDE_INT *pbitsize, HOST_WIDE_INT *pbitpos, tree *poffset, enum machine_mode *pmode, int *punsignedp, - int *pvolatilep) + int *pvolatilep, bool keep_aligning) { tree size_tree = 0; enum machine_mode mode = VOIDmode; @@ -5352,14 +5366,10 @@ get_inner_reference (tree exp, HOST_WIDE_INT *pbitsize, bitsize_int (*pbitsize)); break; - /* We can go inside most conversions: all NON_VALUE_EXPRs, all normal - conversions that don't change the mode, and all view conversions - except those that need to "step up" the alignment. */ - case VIEW_CONVERT_EXPR: - if ((TYPE_ALIGN (TREE_TYPE (exp)) + if (keep_aligning && STRICT_ALIGNMENT + && (TYPE_ALIGN (TREE_TYPE (exp)) > TYPE_ALIGN (TREE_TYPE (TREE_OPERAND (exp, 0)))) - && STRICT_ALIGNMENT && (TYPE_ALIGN (TREE_TYPE (TREE_OPERAND (exp, 0))) < BIGGEST_ALIGNMENT) && (TYPE_ALIGN_OK (TREE_TYPE (exp)) @@ -6082,8 +6092,13 @@ expand_expr_addr_expr_1 (tree exp, rtx target, enum machine_mode tmode, return result; } + /* Pass FALSE as the last argument to get_inner_reference although + we are expanding to RTL. The rationale is that we know how to + handle "aligning nodes" here: we can just bypass them because + they won't change the final object whose address will be returned + (they actually exist only for that purpose). */ inner = get_inner_reference (exp, &bitsize, &bitpos, &offset, - &mode1, &unsignedp, &volatilep); + &mode1, &unsignedp, &volatilep, false); break; } @@ -6908,7 +6923,7 @@ expand_expr_real_1 (tree exp, rtx target, enum machine_mode tmode, tree offset; int volatilep = 0; tree tem = get_inner_reference (exp, &bitsize, &bitpos, &offset, - &mode1, &unsignedp, &volatilep); + &mode1, &unsignedp, &volatilep, true); rtx orig_op0; /* If we got back the original object, something is wrong. Perhaps |