re PR tree-optimization/84503 (store-merging miscompilation on powerpc64 with -O3 since r241789)
PR tree-optimization/84503 * gimple-ssa-store-merging.c (merged_store_group::merge_into): Compute width as info->bitpos + info->bitsize - start. (merged_store_group::merge_overlapping): Simplify width computation. (check_no_overlap): New function. (imm_store_chain_info::try_coalesce_bswap): Compute expected start + width and last_order of the group, fail if check_no_overlap fails. (imm_store_chain_info::coalesce_immediate_stores): Don't merge info to group if check_no_overlap fails. * gcc.dg/pr84503-1.c: New test. * gcc.dg/pr84503-2.c: New test. From-SVN: r257891
This commit is contained in:
Jakub Jelinek
Jakub Jelinek
parent
ad18eed284
commit
c5679c37aa
5 changed files with 169 additions and 21 deletions
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@ -1,3 +1,16 @@
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2018-02-22 Jakub Jelinek <jakub@redhat.com>
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PR tree-optimization/84503
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* gimple-ssa-store-merging.c (merged_store_group::merge_into): Compute
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width as info->bitpos + info->bitsize - start.
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(merged_store_group::merge_overlapping): Simplify width computation.
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(check_no_overlap): New function.
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(imm_store_chain_info::try_coalesce_bswap): Compute expected
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start + width and last_order of the group, fail if check_no_overlap
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fails.
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(imm_store_chain_info::coalesce_immediate_stores): Don't merge info
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to group if check_no_overlap fails.
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2018-02-21 Segher Boessenkool <segher@kernel.crashing.org>
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* config/rs6000/altivec.md: Delete contraint arguments to
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@ -1891,12 +1891,11 @@ merged_store_group::do_merge (store_immediate_info *info)
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void
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merged_store_group::merge_into (store_immediate_info *info)
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{
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unsigned HOST_WIDE_INT wid = info->bitsize;
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/* Make sure we're inserting in the position we think we're inserting. */
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gcc_assert (info->bitpos >= start + width
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&& info->bitregion_start <= bitregion_end);
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width += wid;
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width = info->bitpos + info->bitsize - start;
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do_merge (info);
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}
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@ -1909,7 +1908,7 @@ merged_store_group::merge_overlapping (store_immediate_info *info)
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{
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/* If the store extends the size of the group, extend the width. */
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if (info->bitpos + info->bitsize > start + width)
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width += info->bitpos + info->bitsize - (start + width);
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width = info->bitpos + info->bitsize - start;
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do_merge (info);
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}
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@ -2304,6 +2303,55 @@ gather_bswap_load_refs (vec<tree> *refs, tree val)
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}
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}
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/* Check if there are any stores in M_STORE_INFO after index I
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(where M_STORE_INFO must be sorted by sort_by_bitpos) that overlap
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a potential group ending with END that have their order
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smaller than LAST_ORDER. RHS_CODE is the kind of store in the
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group. Return true if there are no such stores.
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Consider:
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MEM[(long long int *)p_28] = 0;
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MEM[(long long int *)p_28 + 8B] = 0;
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MEM[(long long int *)p_28 + 16B] = 0;
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MEM[(long long int *)p_28 + 24B] = 0;
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_129 = (int) _130;
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MEM[(int *)p_28 + 8B] = _129;
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MEM[(int *)p_28].a = -1;
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We already have
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MEM[(long long int *)p_28] = 0;
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MEM[(int *)p_28].a = -1;
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stmts in the current group and need to consider if it is safe to
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add MEM[(long long int *)p_28 + 8B] = 0; store into the same group.
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There is an overlap between that store and the MEM[(int *)p_28 + 8B] = _129;
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store though, so if we add the MEM[(long long int *)p_28 + 8B] = 0;
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into the group and merging of those 3 stores is successful, merged
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stmts will be emitted at the latest store from that group, i.e.
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LAST_ORDER, which is the MEM[(int *)p_28].a = -1; store.
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The MEM[(int *)p_28 + 8B] = _129; store that originally follows
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the MEM[(long long int *)p_28 + 8B] = 0; would now be before it,
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so we need to refuse merging MEM[(long long int *)p_28 + 8B] = 0;
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into the group. That way it will be its own store group and will
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not be touched. If RHS_CODE is INTEGER_CST and there are overlapping
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INTEGER_CST stores, those are mergeable using merge_overlapping,
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so don't return false for those. */
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static bool
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check_no_overlap (vec<store_immediate_info *> m_store_info, unsigned int i,
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enum tree_code rhs_code, unsigned int last_order,
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unsigned HOST_WIDE_INT end)
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{
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unsigned int len = m_store_info.length ();
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for (++i; i < len; ++i)
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{
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store_immediate_info *info = m_store_info[i];
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if (info->bitpos >= end)
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break;
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if (info->order < last_order
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&& (rhs_code != INTEGER_CST || info->rhs_code != INTEGER_CST))
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return false;
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}
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return true;
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}
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/* Return true if m_store_info[first] and at least one following store
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form a group which store try_size bitsize value which is byte swapped
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from a memory load or some value, or identity from some value.
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@ -2375,6 +2423,7 @@ imm_store_chain_info::try_coalesce_bswap (merged_store_group *merged_store,
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unsigned int last_order = merged_store->last_order;
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gimple *first_stmt = merged_store->first_stmt;
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gimple *last_stmt = merged_store->last_stmt;
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unsigned HOST_WIDE_INT end = merged_store->start + merged_store->width;
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store_immediate_info *infof = m_store_info[first];
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for (unsigned int i = first; i <= last; ++i)
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@ -2413,25 +2462,23 @@ imm_store_chain_info::try_coalesce_bswap (merged_store_group *merged_store,
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}
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else
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{
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if (n.base_addr)
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if (n.base_addr && n.vuse != this_n.vuse)
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{
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if (n.vuse != this_n.vuse)
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{
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if (vuse_store == 0)
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return false;
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vuse_store = 1;
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}
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if (info->order > last_order)
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{
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last_order = info->order;
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last_stmt = info->stmt;
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}
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else if (info->order < first_order)
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{
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first_order = info->order;
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first_stmt = info->stmt;
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}
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if (vuse_store == 0)
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return false;
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vuse_store = 1;
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}
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if (info->order > last_order)
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{
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last_order = info->order;
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last_stmt = info->stmt;
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}
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else if (info->order < first_order)
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{
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first_order = info->order;
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first_stmt = info->stmt;
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}
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end = MAX (end, info->bitpos + info->bitsize);
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ins_stmt = perform_symbolic_merge (ins_stmt, &n, info->ins_stmt,
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&this_n, &n);
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@ -2452,6 +2499,9 @@ imm_store_chain_info::try_coalesce_bswap (merged_store_group *merged_store,
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if (n.base_addr == NULL_TREE && !is_gimple_val (n.src))
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return false;
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if (!check_no_overlap (m_store_info, last, LROTATE_EXPR, last_order, end))
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return false;
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/* Don't handle memory copy this way if normal non-bswap processing
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would handle it too. */
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if (n.n == cmpnop && (unsigned) n.n_ops == last - first + 1)
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@ -2633,7 +2683,13 @@ imm_store_chain_info::coalesce_immediate_stores ()
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: !info->ops[0].base_addr)
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&& (infof->ops[1].base_addr
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? compatible_load_p (merged_store, info, base_addr, 1)
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: !info->ops[1].base_addr))
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: !info->ops[1].base_addr)
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&& check_no_overlap (m_store_info, i, info->rhs_code,
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MAX (merged_store->last_order,
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info->order),
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MAX (merged_store->start
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+ merged_store->width,
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info->bitpos + info->bitsize)))
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{
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merged_store->merge_into (info);
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continue;
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@ -1,3 +1,9 @@
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2018-02-22 Jakub Jelinek <jakub@redhat.com>
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PR tree-optimization/84503
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* gcc.dg/pr84503-1.c: New test.
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* gcc.dg/pr84503-2.c: New test.
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2018-02-21 Jakub Jelinek <jakub@redhat.com>
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PR tree-optimization/84478
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68
gcc/testsuite/gcc.dg/pr84503-1.c
Normal file
68
gcc/testsuite/gcc.dg/pr84503-1.c
Normal file
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@ -0,0 +1,68 @@
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/* PR tree-optimization/84503 */
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/* { dg-do run } */
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/* { dg-options "-O3" } */
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typedef __SIZE_TYPE__ size_t;
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typedef __UINTPTR_TYPE__ uintptr_t;
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struct S { int a; unsigned short b; int c, d, e; long f, g, h; int i, j; };
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static struct S *k;
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static size_t l = 0;
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int m;
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static int
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bar (void)
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{
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unsigned i;
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int j;
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if (k[0].c == 0)
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{
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++m;
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size_t n = l * 2;
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struct S *o;
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o = (struct S *) __builtin_realloc (k, sizeof (struct S) * n);
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if (!o)
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__builtin_exit (0);
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k = o;
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for (i = l; i < n; i++)
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{
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void *p = (void *) &k[i];
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int q = 0;
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size_t r = sizeof (struct S);
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if ((((uintptr_t) p) % __alignof__ (long)) == 0
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&& r % sizeof (long) == 0)
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{
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long __attribute__ ((may_alias)) *s = (long *) p;
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long *t = (long *) ((char *) s + r);
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while (s < t)
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*s++ = 0;
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}
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else
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__builtin_memset (p, q, r);
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k[i].c = i + 1;
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k[i].a = -1;
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}
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k[n - 1].c = 0;
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k[0].c = l;
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l = n;
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}
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j = k[0].c;
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k[0].c = k[j].c;
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return j;
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}
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int
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main ()
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{
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k = (struct S *) __builtin_malloc (sizeof (struct S));
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if (!k)
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__builtin_exit (0);
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__builtin_memset (k, '\0', sizeof (struct S));
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k->a = -1;
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l = 1;
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for (int i = 0; i < 15; ++i)
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bar ();
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if (m != 4)
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__builtin_abort ();
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return 0;
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}
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5
gcc/testsuite/gcc.dg/pr84503-2.c
Normal file
5
gcc/testsuite/gcc.dg/pr84503-2.c
Normal file
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@ -0,0 +1,5 @@
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/* PR tree-optimization/84503 */
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/* { dg-do run } */
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/* { dg-options "-O3 -fno-tree-vectorize -fno-ivopts" } */
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#include "pr84503-1.c"
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