On Mon, Nov 25, 2013 at 7:41 PM, Jeff Law <[email protected]> wrote:
> On 11/25/13 02:22, bin.cheng wrote:
>>
>> Hi,
>> I previously committed two patches lowering complex address expression for
>> IVOPT at http://gcc.gnu.org/ml/gcc-patches/2013-11/msg00546.html and
>> http://gcc.gnu.org/ml/gcc-patches/2013-11/msg01103.html
>> When I bootstrapping GCC I found there were some peculiar cases like
>> &MEM[ptr+CST] + xxxx, which should be handled too. This patch consists
>> below two changes:
>>
>> 1) change in alloc_iv:
>> Original code lowers top level complex address expressions like
>> &MEM[ptr+off]. The patch relaxes check condition in order to lower
>> expressions like &MEM[ptr+off] + xxx, just as the BASE from below dump:
>> use 2
>> generic
>> in statement _595 = &MEM[(void *)&this_prg + 36B] + _594;
>>
>> at position
>> type struct gcov_bucket_type *
>> base (struct gcov_bucket_type *) &MEM[(void *)&this_prg + 36B] +
>> (sizetype) ((unsigned int) (src_i_683 + -1) * 20)
>> step 4294967276
>> base object (void *) &this_prg
>> related candidates
>>
>> 2) change in tree_to_aff_combination:
>> The function get_inner_reference returns "&MEM[ptr+off]" as the core for
>> input like the memory ADDRESS in below dump:
>> use 2
>> address
>> in statement _59 = MEM[(const struct gcov_ctr_summary *)summary_22(D) +
>> 4B].histogram[h_ix_111].min_value;
>>
>> at position MEM[(const struct gcov_ctr_summary *)summary_22(D) +
>> 4B].histogram[h_ix_111].min_value
>> type const gcov_type *
>> base (const gcov_type *) &MEM[(const struct gcov_ctr_summary
>> *)summary_22(D) + 4B] + 36
>> step 20
>> base object (void *) summary_22(D)
>> related candidates
>>
>> Which can be further reduced into something like "summary_22(D) + 40B".
>> This change is necessary for the first one, because I am using
>> tree_to_aff_combination rather than get_inner_reference_aff now.
>>
>> Bootstrap and test on x86/x86_64/arm. Is it OK?
>>
>> Thanks.
>> bin
>>
>> 2013-11-25 Bin Cheng <[email protected]>
>>
>> * tree-ssa-loop-ivopts.c (contain_complex_addr_expr): New.
>> (alloc_iv): Lower more cases by calling contain_complex_addr_expr
>> and tree_to_aff_combination.
>> * tree-affine.c (tree_to_aff_combination): Handle &MEM[ptr+CST]
>> in core part of complex reference.
>>
>> gcc/testsuite/ChangeLog
>> 2013-11-25 Bin Cheng <[email protected]>
>>
>> * gcc.dg/tree-ssa/ivopts-lower_base.c: New test.
>
> Unless there's a PR for this problem, I think this needs to wait.
I agree. Btw, please split the patch.
Index: gcc/tree-affine.c
===================================================================
--- gcc/tree-affine.c (revision 205087)
+++ gcc/tree-affine.c (working copy)
@@ -328,7 +328,19 @@ tree_to_aff_combination (tree expr, tree type, aff
double_int::from_uhwi (bitpos / BITS_PER_UNIT));
core = build_fold_addr_expr (core);
if (TREE_CODE (core) == ADDR_EXPR)
- aff_combination_add_elt (comb, core, double_int_one);
+ {
+ /* Handle &MEM[ptr + CST] in core part of complex reference. */
+ if (TREE_CODE (TREE_OPERAND (core, 0)) == MEM_REF)
+ {
+ core = TREE_OPERAND (core, 0);
+ tree_to_aff_combination (TREE_OPERAND (core, 0), type, &tmp);
+ aff_combination_add (comb, &tmp);
+ tree_to_aff_combination (TREE_OPERAND (core, 1), sizetype, &tmp);
+ aff_combination_add (comb, &tmp);
+ }
+ else
+ aff_combination_add_elt (comb, core, double_int_one);
+ }
else
{
tree_to_aff_combination (core, type, &tmp)
please handle the offset before taking the address, thus
if (TREE_CODE (core) == MEM_REF)
{
add constant offset;
core = TREE_OPERAND (core, 0);
}
else
core = build_fold_addr_expr (core);
that simplifies things and avoids the address building.
Richard.
> jeff
>
>
