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re PR debug/43077 (VTA issues caused by SSA expand)

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PR debug/43077
	* cfgexpand (expand_debug_expr): Expand TERed ssa names in place.
	(expand_gimple_basic_block): Generate and use debug temps if there
	are debug uses left after the last real use of TERed ssa names.
	Unlink debug immediate uses when they are expanded.

testsuite/
	PR debug/43077
	* gcc.dg/guality/pr43077-1.c: New test.

From-SVN: r157009
This commit is contained in:
Michael Matz 2010-02-23 16:41:52 +00:00
parent 38170f34f3
commit 2a8e30fbf3
4 changed files with 194 additions and 6 deletions
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8
gcc/ChangeLog
View File

@ -1,3 +1,11 @@
2010-02-23 Michael Matz <matz@suse.de>
PR debug/43077
* cfgexpand (expand_debug_expr): Expand TERed ssa names in place.
(expand_gimple_basic_block): Generate and use debug temps if there
are debug uses left after the last real use of TERed ssa names.
Unlink debug immediate uses when they are expanded.
2010-02-23 Manuel López-Ibáñez <manu@gcc.gnu.org>
PR 43123

132
gcc/cfgexpand.c
View File

@ -2338,7 +2338,10 @@ expand_debug_expr (tree exp)
if (inner_mode == VOIDmode)
{
inner_mode = TYPE_MODE (TREE_TYPE (TREE_OPERAND (exp, 0)));
if (TREE_CODE (exp) == SSA_NAME)
inner_mode = TYPE_MODE (TREE_TYPE (exp));
else
inner_mode = TYPE_MODE (TREE_TYPE (TREE_OPERAND (exp, 0)));
if (mode == inner_mode)
return op0;
}
@ -2354,6 +2357,7 @@ expand_debug_expr (tree exp)
}
else if (FLOAT_MODE_P (mode))
{
gcc_assert (TREE_CODE (exp) != SSA_NAME);
if (TYPE_UNSIGNED (TREE_TYPE (TREE_OPERAND (exp, 0))))
op0 = simplify_gen_unary (UNSIGNED_FLOAT, mode, op0, inner_mode);
else
@ -2886,14 +2890,24 @@ expand_debug_expr (tree exp)
case SSA_NAME:
{
int part = var_to_partition (SA.map, exp);
gimple g = get_gimple_for_ssa_name (exp);
if (g)
{
op0 = expand_debug_expr (gimple_assign_rhs_to_tree (g));
if (!op0)
return NULL;
}
else
{
int part = var_to_partition (SA.map, exp);
if (part == NO_PARTITION)
return NULL;
if (part == NO_PARTITION)
return NULL;
gcc_assert (part >= 0 && (unsigned)part < SA.map->num_partitions);
gcc_assert (part >= 0 && (unsigned)part < SA.map->num_partitions);
op0 = SA.partition_to_pseudo[part];
op0 = SA.partition_to_pseudo[part];
}
goto adjust_mode;
}
@ -3050,6 +3064,105 @@ expand_gimple_basic_block (basic_block bb)
basic_block new_bb;
stmt = gsi_stmt (gsi);
/* If this statement is a non-debug one, and we generate debug
insns, then this one might be the last real use of a TERed
SSA_NAME, but where there are still some debug uses further
down. Expanding the current SSA name in such further debug
uses by their RHS might lead to wrong debug info, as coalescing
might make the operands of such RHS be placed into the same
pseudo as something else. Like so:
a_1 = a_0 + 1; // Assume a_1 is TERed and a_0 is dead
use(a_1);
a_2 = ...
#DEBUG ... => a_1
As a_0 and a_2 don't overlap in lifetime, assume they are coalesced.
If we now would expand a_1 by it's RHS (a_0 + 1) in the debug use,
the write to a_2 would actually have clobbered the place which
formerly held a_0.
So, instead of that, we recognize the situation, and generate
debug temporaries at the last real use of TERed SSA names:
a_1 = a_0 + 1;
#DEBUG #D1 => a_1
use(a_1);
a_2 = ...
#DEBUG ... => #D1
*/
if (MAY_HAVE_DEBUG_INSNS
&& SA.values
&& !is_gimple_debug (stmt))
{
ssa_op_iter iter;
tree op;
gimple def;
location_t sloc = get_curr_insn_source_location ();
tree sblock = get_curr_insn_block ();
/* Look for SSA names that have their last use here (TERed
names always have only one real use). */
FOR_EACH_SSA_TREE_OPERAND (op, stmt, iter, SSA_OP_USE)
if ((def = get_gimple_for_ssa_name (op)))
{
imm_use_iterator imm_iter;
use_operand_p use_p;
bool have_debug_uses = false;
FOR_EACH_IMM_USE_FAST (use_p, imm_iter, op)
{
if (gimple_debug_bind_p (USE_STMT (use_p)))
{
have_debug_uses = true;
break;
}
}
if (have_debug_uses)
{
/* OP is a TERed SSA name, with DEF it's defining
statement, and where OP is used in further debug
instructions. Generate a debug temporary, and
replace all uses of OP in debug insns with that
temporary. */
gimple debugstmt;
tree value = gimple_assign_rhs_to_tree (def);
tree vexpr = make_node (DEBUG_EXPR_DECL);
rtx val;
enum machine_mode mode;
set_curr_insn_source_location (gimple_location (def));
set_curr_insn_block (gimple_block (def));
DECL_ARTIFICIAL (vexpr) = 1;
TREE_TYPE (vexpr) = TREE_TYPE (value);
if (DECL_P (value))
mode = DECL_MODE (value);
else
mode = TYPE_MODE (TREE_TYPE (value));
DECL_MODE (vexpr) = mode;
val = gen_rtx_VAR_LOCATION
(mode, vexpr, (rtx)value, VAR_INIT_STATUS_INITIALIZED);
val = emit_debug_insn (val);
FOR_EACH_IMM_USE_STMT (debugstmt, imm_iter, op)
{
if (!gimple_debug_bind_p (debugstmt))
continue;
FOR_EACH_IMM_USE_ON_STMT (use_p, imm_iter)
SET_USE (use_p, vexpr);
update_stmt (debugstmt);
}
}
}
set_curr_insn_source_location (sloc);
set_curr_insn_block (sblock);
}
currently_expanding_gimple_stmt = stmt;
/* Expand this statement, then evaluate the resulting RTL and
@ -3102,6 +3215,13 @@ expand_gimple_basic_block (basic_block bb)
INSN_VAR_LOCATION_LOC (val) = (rtx)value;
}
/* In order not to generate too many debug temporaries,
we delink all uses of debug statements we already expanded.
Therefore debug statements between definition and real
use of TERed SSA names will continue to use the SSA name,
and not be replaced with debug temps. */
delink_stmt_imm_use (stmt);
gsi = nsi;
gsi_next (&nsi);
if (gsi_end_p (nsi))

5
gcc/testsuite/ChangeLog
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@ -1,3 +1,8 @@
2010-02-23 Jakub Jelinek <jakub@redhat.com>
PR debug/43077
* gcc.dg/guality/pr43077-1.c: New test.
2010-02-23 Manuel López-Ibáñez <manu@gcc.gnu.org>
PR 43123

55
gcc/testsuite/gcc.dg/guality/pr43077-1.c Normal file
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@ -0,0 +1,55 @@
/* PR debug/43077 */
/* { dg-do run } */
/* { dg-options "-g" } */
int varb;
int __attribute__((noinline))
fn1 (void)
{
int vara = (varb == 3); /* { dg-final { gdb-test 11 "vara" "0" } } */
asm volatile ("" : : "g" (vara)); /* { dg-final { gdb-test 11 "varb" "2" } } */
return 0;
}
int __attribute__((noinline))
fn2 (void)
{
int vara = (varb == 3); /* { dg-final { gdb-test 19 "vara" "1" } } */
asm volatile ("" : : "g" (vara)); /* { dg-final { gdb-test 19 "varb" "3" } } */
return 0;
}
int __attribute__((noinline))
foo (unsigned long *p, unsigned long *q)
{
int ret;
asm volatile ("" : "=r" (ret), "=r" (*p), "=r" (*q) : "0" (1), "1" (2), "2" (3));
return ret;
}
int __attribute__((noinline))
fn3 (void)
{
unsigned long a = 0, b = 0, c = 0;
a = foo (&b, &c);
/* { dg-final { gdb-test 42 "a" "1" } } */
/* { dg-final { gdb-test 42 "b" "2" } } */
/* { dg-final { gdb-test 42 "c" "3" } } */
unsigned long vara = a; /* { dg-final { gdb-test 42 "vara" "1" } } */
unsigned long varb = b; /* { dg-final { gdb-test 42 "varb" "2" } } */
unsigned long varc = c; /* { dg-final { gdb-test 42 "varc" "3" } } */
asm volatile ("" : : "g" (vara), "g" (varb), "g" (varc));
return a;
}
int
main (void)
{
asm volatile ("" : "=r" (varb) : "0" (2));
fn1 ();
asm volatile ("" : "=r" (varb) : "0" (3));
fn2 ();
fn3 ();
return 0;
}