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expr.c (is_aligning_offset): New function. 

* expr.c (is_aligning_offset): New function.
	(expand_expr, case COMPONENT_EXPR): Call it.

From-SVN: r52076
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Richard Kenner 2002-04-09 13:40:36 +00:00 committed by Richard Kenner
parent a129752b4e
commit 47a036ed46
2 changed files with 62 additions and 0 deletions
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5
gcc/ChangeLog
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@ -1,3 +1,8 @@
Tue Apr 9 09:35:45 2002 Richard Kenner <kenner@vlsi1.ultra.nyu.edu>
* expr.c (is_aligning_offset): New function.
(expand_expr, case COMPONENT_EXPR): Call it.
2002-04-09 Alan Modra <amodra@bigpond.net.au>
* configure.in (auto-build.h): Use target_alias and build_alias

57
gcc/expr.c
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@ -147,6 +147,7 @@ static rtx store_field PARAMS ((rtx, HOST_WIDE_INT,
int));
static rtx var_rtx PARAMS ((tree));
static HOST_WIDE_INT highest_pow2_factor PARAMS ((tree));
static int is_aligning_offset PARAMS ((tree, tree));
static rtx expand_increment PARAMS ((tree, int, int));
static void do_jump_by_parts_greater PARAMS ((tree, int, rtx, rtx));
static void do_jump_by_parts_equality PARAMS ((tree, rtx, rtx));
@ -6928,6 +6929,12 @@ expand_expr (exp, target, tmode, modifier)
highest_pow2_factor (offset));
}
/* If OFFSET is making OP0 more aligned than BIGGEST_ALIGNMENT,
record its alignment as BIGGEST_ALIGNMENT. */
if (GET_CODE (op0) == MEM && bitpos == 0 && offset != 0
&& is_aligning_offset (offset, tem))
set_mem_align (op0, BIGGEST_ALIGNMENT);
/* Don't forget about volatility even if this is a bitfield. */
if (GET_CODE (op0) == MEM && volatilep && ! MEM_VOLATILE_P (op0))
{
@ -8802,6 +8809,56 @@ expand_expr (exp, target, tmode, modifier)
return temp;
}
/* Subroutine of above: returns 1 if OFFSET corresponds to an offset that
when applied to the address of EXP produces an address known to be
aligned more than BIGGEST_ALIGNMENT. */
static int
is_aligning_offset (offset, exp)
tree offset;
tree exp;
{
/* Strip off any conversions and WITH_RECORD_EXPR nodes. */
while (TREE_CODE (offset) == NON_LVALUE_EXPR
|| TREE_CODE (offset) == NOP_EXPR
|| TREE_CODE (offset) == CONVERT_EXPR
|| TREE_CODE (offset) == WITH_RECORD_EXPR)
offset = TREE_OPERAND (offset, 0);
/* We must now have a BIT_AND_EXPR with a constant that is one less than
power of 2 and which is larger than BIGGEST_ALIGNMENT. */
if (TREE_CODE (offset) != BIT_AND_EXPR
|| !host_integerp (TREE_OPERAND (offset, 1), 1)
|| compare_tree_int (TREE_OPERAND (offset, 1), BIGGEST_ALIGNMENT) <= 0
|| !exact_log2 (tree_low_cst (TREE_OPERAND (offset, 1), 1) + 1) < 0)
return 0;
/* Look at the first operand of BIT_AND_EXPR and strip any conversion.
It must be NEGATE_EXPR. Then strip any more conversions. */
offset = TREE_OPERAND (offset, 0);
while (TREE_CODE (offset) == NON_LVALUE_EXPR
|| TREE_CODE (offset) == NOP_EXPR
|| TREE_CODE (offset) == CONVERT_EXPR)
offset = TREE_OPERAND (offset, 0);
if (TREE_CODE (offset) != NEGATE_EXPR)
return 0;
offset = TREE_OPERAND (offset, 0);
while (TREE_CODE (offset) == NON_LVALUE_EXPR
|| TREE_CODE (offset) == NOP_EXPR
|| TREE_CODE (offset) == CONVERT_EXPR)
offset = TREE_OPERAND (offset, 0);
/* This must now be the address either of EXP or of a PLACEHOLDER_EXPR
whose type is the same as EXP. */
return (TREE_CODE (offset) == ADDR_EXPR
&& (TREE_OPERAND (offset, 0) == exp
|| (TREE_CODE (TREE_OPERAND (offset, 0)) == PLACEHOLDER_EXPR
&& (TREE_TYPE (TREE_OPERAND (offset, 0))
== TREE_TYPE (exp)))));
}
/* Return the tree node if a ARG corresponds to a string constant or zero
if it doesn't. If we return non-zero, set *PTR_OFFSET to the offset
in bytes within the string that ARG is accessing. The type of the