[PATCH] (another one) Fix PR33870, PTA and partitoning interaction
Richard Guenther
rguenther@suse.de
Fri Oct 26 14:54:00 GMT 2007
On Wed, 24 Oct 2007, Daniel Berlin wrote:
> On 10/24/07, Richard Guenther <rguenther@suse.de> wrote:
> > On Wed, 24 Oct 2007, Daniel Berlin wrote:
> >
> > > On 10/24/07, Richard Guenther <rguenther@suse.de> wrote:
> > > >
> > > > So, as opposed to the earlier patch which papered over one specific case
> > > > of the problem (which is that alias partitioning rips apart SFTs belonging
> > > > to the same parent variable), this is a hammer that really solves it
> > > > but at a cost (maybe, to be investigated).
> > > >
> > > > IMHO the operand scanning part of accesses through pointers is fragile
> > > > in that it requires that the full set of SFTs that possibly are addressed
> > > > by the pointer is available together as aliases of a symbol.
> > >
> > > Actually, it only requires that the points-to sets be correct :)
> >
> > But we don't use the points-to set. We use the aliased bitmap.
>
> Feel free to keep the ptset around for 4.3 (i think we already do),
> and just use that.
> I'd happily approve that.
I tried and it's not too easy. But the following works and should do
the equivalent thing by looking into MPTs.
Bootstrapped on x86_64-unknown-linux-gnu, testing in progress.
Ok if that passes?
Richard.
2007-10-26 Richard Guenther <rguenther@suse.de>
PR tree-optimization/33870
* tree-ssa-operands.c (add_vars_for_offset): Reduce code
duplication. Remove redundant call to access_can_touch_variable.
(add_vars_for_bitmap): New helper for recursing over MPT contents.
(add_virtual_operand): Use it.
* gcc.dg/tree-ssa/alias-15.c: New testcase.
* gcc.c-torture/execute/pr33870.c: Likewise.
Index: tree-ssa-operands.c
===================================================================
--- tree-ssa-operands.c (revision 129646)
+++ tree-ssa-operands.c (working copy)
@@ -1419,55 +1419,57 @@ add_vars_for_offset (tree full_ref, tree
}
else if (TREE_CODE (var) == STRUCT_FIELD_TAG)
{
- if (size == -1)
+ bool added = false;
+ subvar_t sv = get_subvars_for_var (SFT_PARENT_VAR (var));
+ for (; sv; sv = sv->next)
{
- bool added = false;
- subvar_t sv = get_subvars_for_var (SFT_PARENT_VAR (var));
- for (; sv; sv = sv->next)
- {
- if (overlap_subvar (SFT_OFFSET (var) + offset, size,
- sv->var, NULL)
- && access_can_touch_variable (full_ref, sv->var,
- offset, size))
- {
- added = true;
- if (is_def)
- append_vdef (sv->var);
- else
- append_vuse (sv->var);
- }
- }
- return added;
- }
- else
- {
- bool added = false;
- subvar_t sv = get_subvars_for_var (SFT_PARENT_VAR (var));
- for (; sv; sv = sv->next)
+ /* Once we hit the end of the parts that could touch,
+ stop looking. */
+ if (size != -1
+ && SFT_OFFSET (var) + offset + size <= SFT_OFFSET (sv->var))
+ break;
+ if (overlap_subvar (SFT_OFFSET (var) + offset, size, sv->var, NULL))
{
- /* Once we hit the end of the parts that could touch,
- stop looking. */
- if (SFT_OFFSET (var) + offset + size <= SFT_OFFSET (sv->var))
- break;
- if (overlap_subvar (SFT_OFFSET (var) + offset, size,
- sv->var, NULL)
- && access_can_touch_variable (full_ref, sv->var, offset,
- size))
- {
- added = true;
- if (is_def)
- append_vdef (sv->var);
- else
- append_vuse (sv->var);
- }
+ added = true;
+ if (is_def)
+ append_vdef (sv->var);
+ else
+ append_vuse (sv->var);
}
- return added;
}
+ return added;
}
return false;
}
+/* Add all aliases from ALIASES as virtual operands for the access
+ FULL_REF at OFFSET and size SIZE. IS_CALL_SITE is true if the
+ stmt of the reference is a call. IS_DEF is true if we should add
+ VDEF virtual operands, otherwise we'll add VUSEs. *NONE_ADDED
+ is set to false once the first virtual operand was added. */
+
+static void
+add_vars_for_bitmap (bitmap aliases, tree full_ref,
+ HOST_WIDE_INT offset, HOST_WIDE_INT size,
+ bool is_call_site, bool is_def, bool *none_added)
+{
+ bitmap_iterator bi;
+ unsigned int i;
+
+ EXECUTE_IF_SET_IN_BITMAP (aliases, 0, i, bi)
+ {
+ tree al = referenced_var (i);
+
+ if (TREE_CODE (al) == MEMORY_PARTITION_TAG)
+ add_vars_for_bitmap (MPT_SYMBOLS (al), full_ref,
+ offset, size, is_call_site, is_def, none_added);
+ else
+ *none_added &= !add_vars_for_offset (full_ref, al, offset, size,
+ is_call_site, is_def);
+ }
+}
+
/* Add VAR to the virtual operands array. FLAGS is as in
get_expr_operands. FULL_REF is a tree that contains the entire
pointer dereference expression, if available, or NULL otherwise.
@@ -1530,24 +1532,17 @@ add_virtual_operand (tree var, stmt_ann_
}
else
{
- bitmap_iterator bi;
- unsigned int i;
- tree al;
+ bool none_added = true;
/* The variable is aliased. Add its aliases to the virtual
operands. */
gcc_assert (!bitmap_empty_p (aliases));
-
+
+ add_vars_for_bitmap (aliases, full_ref, offset, size,
+ is_call_site, flags & opf_def, &none_added);
+
if (flags & opf_def)
{
- bool none_added = true;
- EXECUTE_IF_SET_IN_BITMAP (aliases, 0, i, bi)
- {
- al = referenced_var (i);
- none_added &= !add_vars_for_offset (full_ref, al, offset, size,
- is_call_site, true);
- }
-
/* If the variable is also an alias tag, add a virtual
operand for it, otherwise we will miss representing
references to the members of the variable's alias set.
@@ -1566,15 +1561,6 @@ add_virtual_operand (tree var, stmt_ann_
}
else
{
- bool none_added = true;
- EXECUTE_IF_SET_IN_BITMAP (aliases, 0, i, bi)
- {
- al = referenced_var (i);
- none_added &= !add_vars_for_offset (full_ref, al, offset, size,
- is_call_site, false);
-
- }
-
/* Even if no aliases have been added, we still need to
establish def-use and use-def chains, lest
transformations think that this is not a memory
Index: testsuite/gcc.c-torture/execute/pr33870.c
===================================================================
*** testsuite/gcc.c-torture/execute/pr33870.c (revision 0)
--- testsuite/gcc.c-torture/execute/pr33870.c (revision 0)
***************
*** 0 ****
--- 1,87 ----
+ extern void abort (void);
+
+ typedef struct PgHdr PgHdr;
+ typedef unsigned char u8;
+ struct PgHdr {
+ unsigned int pgno;
+ PgHdr *pNextHash, *pPrevHash;
+ PgHdr *pNextFree, *pPrevFree;
+ PgHdr *pNextAll;
+ u8 inJournal;
+ short int nRef;
+ PgHdr *pDirty, *pPrevDirty;
+ unsigned int notUsed;
+ };
+
+ static inline PgHdr *merge_pagelist(PgHdr *pA, PgHdr *pB)
+ {
+ PgHdr result;
+ PgHdr *pTail;
+ pTail = &result;
+ while( pA && pB ){
+ if( pA->pgno<pB->pgno ){
+ pTail->pDirty = pA;
+ pTail = pA;
+ pA = pA->pDirty;
+ }else{
+ pTail->pDirty = pB;
+ pTail = pB;
+ pB = pB->pDirty;
+ }
+ }
+ if( pA ){
+ pTail->pDirty = pA;
+ }else if( pB ){
+ pTail->pDirty = pB;
+ }else{
+ pTail->pDirty = 0;
+ }
+ return result.pDirty;
+ }
+
+ PgHdr * __attribute__((noinline)) sort_pagelist(PgHdr *pIn)
+ {
+ PgHdr *a[25], *p;
+ int i;
+ __builtin_memset (a, 0, sizeof (a));
+ while( pIn ){
+ p = pIn;
+ pIn = p->pDirty;
+ p->pDirty = 0;
+ for(i=0; i<25 -1; i++){
+ if( a[i]==0 ){
+ a[i] = p;
+ break;
+ }else{
+ p = merge_pagelist(a[i], p);
+ a[i] = 0;
+ }
+ }
+ if( i==25 -1 ){
+ a[i] = merge_pagelist(a[i], p);
+ }
+ }
+ p = a[0];
+ for(i=1; i<25; i++){
+ p = merge_pagelist (p, a[i]);
+ }
+ return p;
+ }
+
+ int main()
+ {
+ PgHdr a[5];
+ PgHdr *p;
+ a[0].pgno = 5;
+ a[0].pDirty = &a[1];
+ a[1].pgno = 4;
+ a[1].pDirty = &a[2];
+ a[2].pgno = 1;
+ a[2].pDirty = &a[3];
+ a[3].pgno = 3;
+ a[3].pDirty = 0;
+ p = sort_pagelist (&a[0]);
+ if (p->pDirty == p)
+ abort ();
+ return 0;
+ }
Index: testsuite/gcc.dg/tree-ssa/alias-15.c
===================================================================
*** testsuite/gcc.dg/tree-ssa/alias-15.c (revision 0)
--- testsuite/gcc.dg/tree-ssa/alias-15.c (revision 0)
***************
*** 0 ****
--- 1,20 ----
+ /* { dg-do compile } */
+ /* { dg-options "-O -fno-early-inlining -fdump-tree-salias-vops-details" } */
+
+ struct foo {
+ int a;
+ struct X {
+ int b[4];
+ } b;
+ } m;
+ static inline struct X *wrap(struct X *p) { return p; }
+ int test2(void)
+ {
+ struct X *p = wrap(&m.b);
+ /* Both memory references need to alias the same SFT. */
+ return p->b[3] - m.b.b[3];
+ }
+
+ /* { dg-final { scan-tree-dump "SFT.1 created for var m offset 128" "salias" } } */
+ /* { dg-final { scan-tree-dump-times "VUSE <SFT.1_" 2 "salias" } } */
+ /* { dg-final { cleanup-tree-dump "salias" } } */
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