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Fix PR77673: bswap loads passed end of object

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2016-11-25  Thomas Preud'homme  <thomas.preudhomme@arm.com>

    gcc/
    PR tree-optimization/77673
    * tree-ssa-math-opts.c (struct symbolic_number): Add new src field.
    (init_symbolic_number): Initialize src field from src parameter.
    (perform_symbolic_merge): Select most dominated statement as the
    source statement.  Set src field of resulting n structure from the
    input src with the lowest address.
    (find_bswap_or_nop): Rename source_stmt into ins_stmt.
    (bswap_replace): Rename src_stmt into ins_stmt.  Initially get source
    of load from src field rather than insertion statement.  Cancel
    optimization if statement analyzed is not dominated by the insertion
    statement.
    (pass_optimize_bswap::execute): Rename src_stmt to ins_stmt.  Compute
    dominance information.

    gcc/testsuite/
    PR tree-optimization/77673
    * gcc.dg/pr77673.c: New test.

From-SVN: r242869
This commit is contained in:
Thomas Preud'homme 2016-11-25 10:03:38 +00:00 committed by Thomas Preud'homme
parent 605040b41a
commit 83624b6040
4 changed files with 70 additions and 14 deletions
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16
gcc/ChangeLog
View File

@ -1,3 +1,19 @@
2016-11-25 Thomas Preud'homme <thomas.preudhomme@arm.com>
PR tree-optimization/77673
* tree-ssa-math-opts.c (struct symbolic_number): Add new src field.
(init_symbolic_number): Initialize src field from src parameter.
(perform_symbolic_merge): Select most dominated statement as the
source statement. Set src field of resulting n structure from the
input src with the lowest address.
(find_bswap_or_nop): Rename source_stmt into ins_stmt.
(bswap_replace): Rename src_stmt into ins_stmt. Initially get source
of load from src field rather than insertion statement. Cancel
optimization if statement analyzed is not dominated by the insertion
statement.
(pass_optimize_bswap::execute): Rename src_stmt to ins_stmt. Compute
dominance information.
2016-11-25 Eric Botcazou <ebotcazou@adacore.com>
PR ada/67205

5
gcc/testsuite/ChangeLog
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@ -1,3 +1,8 @@
2016-11-25 Thomas Preud'homme <thomas.preudhomme@arm.com>
PR tree-optimization/77673
* gcc.dg/pr77673.c: New test.
2016-11-25 Martin Jambor <mjambor@suse.cz>
PR tree-optimization/70965

19
gcc/testsuite/gcc.dg/pr77673.c Normal file
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@ -0,0 +1,19 @@
/* { dg-do compile { target fpic } } */
/* { dg-require-effective-target bswap32 } */
/* { dg-options "-O2 -fPIC -fdump-tree-bswap" } */
/* { dg-additional-options "-march=z900" { target s390*-*-* } } */
void mach_parse_compressed(unsigned char* ptr, unsigned long int* val)
{
if (ptr[0] < 0xC0U) {
*val = ptr[0] + ptr[1];
return;
}
*val = ((unsigned long int)(ptr[0]) << 24)
| ((unsigned long int)(ptr[1]) << 16)
| ((unsigned long int)(ptr[2]) << 8)
| ptr[3];
}
/* { dg-final { scan-tree-dump-not "load_dst_\\d+ =.* if \\(" "bswap" } } */

44
gcc/tree-ssa-math-opts.c
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@ -1957,6 +1957,7 @@ struct symbolic_number {
tree base_addr;
tree offset;
HOST_WIDE_INT bytepos;
tree src;
tree alias_set;
tree vuse;
unsigned HOST_WIDE_INT range;
@ -2061,6 +2062,7 @@ init_symbolic_number (struct symbolic_number *n, tree src)
return false;
n->base_addr = n->offset = n->alias_set = n->vuse = NULL_TREE;
n->src = src;
/* Set up the symbolic number N by setting each byte to a value between 1 and
the byte size of rhs1. The highest order byte is set to n->size and the
@ -2185,6 +2187,7 @@ perform_symbolic_merge (gimple *source_stmt1, struct symbolic_number *n1,
uint64_t inc;
HOST_WIDE_INT start_sub, end_sub, end1, end2, end;
struct symbolic_number *toinc_n_ptr, *n_end;
basic_block bb1, bb2;
if (!n1->base_addr || !n2->base_addr
|| !operand_equal_p (n1->base_addr, n2->base_addr, 0))
@ -2198,15 +2201,20 @@ perform_symbolic_merge (gimple *source_stmt1, struct symbolic_number *n1,
{
n_start = n1;
start_sub = n2->bytepos - n1->bytepos;
source_stmt = source_stmt1;
}
else
{
n_start = n2;
start_sub = n1->bytepos - n2->bytepos;
source_stmt = source_stmt2;
}
bb1 = gimple_bb (source_stmt1);
bb2 = gimple_bb (source_stmt2);
if (dominated_by_p (CDI_DOMINATORS, bb1, bb2))
source_stmt = source_stmt1;
else
source_stmt = source_stmt2;
/* Find the highest address at which a load is performed and
compute related info. */
end1 = n1->bytepos + (n1->range - 1);
@ -2263,6 +2271,7 @@ perform_symbolic_merge (gimple *source_stmt1, struct symbolic_number *n1,
n->vuse = n_start->vuse;
n->base_addr = n_start->base_addr;
n->offset = n_start->offset;
n->src = n_start->src;
n->bytepos = n_start->bytepos;
n->type = n_start->type;
size = TYPE_PRECISION (n->type) / BITS_PER_UNIT;
@ -2512,7 +2521,7 @@ find_bswap_or_nop (gimple *stmt, struct symbolic_number *n, bool *bswap)
uint64_t cmpxchg = CMPXCHG;
uint64_t cmpnop = CMPNOP;
gimple *source_stmt;
gimple *ins_stmt;
int limit;
/* The last parameter determines the depth search limit. It usually
@ -2522,9 +2531,9 @@ find_bswap_or_nop (gimple *stmt, struct symbolic_number *n, bool *bswap)
in libgcc, and for initial shift/and operation of the src operand. */
limit = TREE_INT_CST_LOW (TYPE_SIZE_UNIT (gimple_expr_type (stmt)));
limit += 1 + (int) ceil_log2 ((unsigned HOST_WIDE_INT) limit);
source_stmt = find_bswap_or_nop_1 (stmt, n, limit);
ins_stmt = find_bswap_or_nop_1 (stmt, n, limit);
if (!source_stmt)
if (!ins_stmt)
return NULL;
/* Find real size of result (highest non-zero byte). */
@ -2576,7 +2585,7 @@ find_bswap_or_nop (gimple *stmt, struct symbolic_number *n, bool *bswap)
return NULL;
n->range *= BITS_PER_UNIT;
return source_stmt;
return ins_stmt;
}
namespace {
@ -2625,7 +2634,7 @@ public:
changing of basic block. */
static bool
bswap_replace (gimple *cur_stmt, gimple *src_stmt, tree fndecl,
bswap_replace (gimple *cur_stmt, gimple *ins_stmt, tree fndecl,
tree bswap_type, tree load_type, struct symbolic_number *n,
bool bswap)
{
@ -2634,25 +2643,31 @@ bswap_replace (gimple *cur_stmt, gimple *src_stmt, tree fndecl,
gimple *bswap_stmt;
gsi = gsi_for_stmt (cur_stmt);
src = gimple_assign_rhs1 (src_stmt);
src = n->src;
tgt = gimple_assign_lhs (cur_stmt);
/* Need to load the value from memory first. */
if (n->base_addr)
{
gimple_stmt_iterator gsi_ins = gsi_for_stmt (src_stmt);
gimple_stmt_iterator gsi_ins = gsi_for_stmt (ins_stmt);
tree addr_expr, addr_tmp, val_expr, val_tmp;
tree load_offset_ptr, aligned_load_type;
gimple *addr_stmt, *load_stmt;
unsigned align;
HOST_WIDE_INT load_offset = 0;
basic_block ins_bb, cur_bb;
ins_bb = gimple_bb (ins_stmt);
cur_bb = gimple_bb (cur_stmt);
if (!dominated_by_p (CDI_DOMINATORS, cur_bb, ins_bb))
return false;
align = get_object_alignment (src);
/* Move cur_stmt just before one of the load of the original
to ensure it has the same VUSE. See PR61517 for what could
go wrong. */
if (gimple_bb (cur_stmt) != gimple_bb (src_stmt))
if (gimple_bb (cur_stmt) != gimple_bb (ins_stmt))
reset_flow_sensitive_info (gimple_assign_lhs (cur_stmt));
gsi_move_before (&gsi, &gsi_ins);
gsi = gsi_for_stmt (cur_stmt);
@ -2827,6 +2842,7 @@ pass_optimize_bswap::execute (function *fun)
memset (&nop_stats, 0, sizeof (nop_stats));
memset (&bswap_stats, 0, sizeof (bswap_stats));
calculate_dominance_info (CDI_DOMINATORS);
FOR_EACH_BB_FN (bb, fun)
{
@ -2838,7 +2854,7 @@ pass_optimize_bswap::execute (function *fun)
variant wouldn't be detected. */
for (gsi = gsi_last_bb (bb); !gsi_end_p (gsi);)
{
gimple *src_stmt, *cur_stmt = gsi_stmt (gsi);
gimple *ins_stmt, *cur_stmt = gsi_stmt (gsi);
tree fndecl = NULL_TREE, bswap_type = NULL_TREE, load_type;
enum tree_code code;
struct symbolic_number n;
@ -2871,9 +2887,9 @@ pass_optimize_bswap::execute (function *fun)
continue;
}
src_stmt = find_bswap_or_nop (cur_stmt, &n, &bswap);
ins_stmt = find_bswap_or_nop (cur_stmt, &n, &bswap);
if (!src_stmt)
if (!ins_stmt)
continue;
switch (n.range)
@ -2907,7 +2923,7 @@ pass_optimize_bswap::execute (function *fun)
if (bswap && !fndecl && n.range != 16)
continue;
if (bswap_replace (cur_stmt, src_stmt, fndecl, bswap_type, load_type,
if (bswap_replace (cur_stmt, ins_stmt, fndecl, bswap_type, load_type,
&n, bswap))
changed = true;
}