[PATCH 1/4] ipa-sra: Do not remove statements necessary because of non-call EH (PR 95113)
Martin Jambor
mjambor@suse.cz
Thu May 28 12:06:35 GMT 2020
PR 95113 revealed that when reasoning about which parameters are dead,
IPA-SRA does not perform the same check related to non-call exceptions
as tree DCE. It most certainly should and so this patch moves the
condition used in tree-ssa-dce.c into a separate predicate (in
tree-eh.c) and uses it from both places.
gcc/ChangeLog:
2020-05-27 Martin Jambor <mjambor@suse.cz>
PR ipa/95113
* gcc/tree-ssa-dce.c (mark_stmt_if_obviously_necessary): Move non-call
exceptions check to...
* gcc/tree-eh.c (stmt_unremovable_because_of_non_call_eh_p): ...this
new function.
* gcc/tree-eh.h (stmt_unremovable_because_of_non_call_eh_p): Declare it.
* gcc/ipa-sra.c (isra_track_scalar_value_uses): Use it. New parameter
fun.
gcc/testsuite/ChangeLog:
2020-05-27 Martin Jambor <mjambor@suse.cz>
PR ipa/95113
* gcc.dg/ipa/pr95113.c: New test.
---
gcc/ipa-sra.c | 28 +++++++++++++------------
gcc/testsuite/gcc.dg/ipa/pr95113.c | 33 ++++++++++++++++++++++++++++++
gcc/tree-eh.c | 10 +++++++++
gcc/tree-eh.h | 1 +
gcc/tree-ssa-dce.c | 4 +---
5 files changed, 60 insertions(+), 16 deletions(-)
create mode 100644 gcc/testsuite/gcc.dg/ipa/pr95113.c
diff --git a/gcc/ipa-sra.c b/gcc/ipa-sra.c
index 7c922e40a4e..c81e8869e7a 100644
--- a/gcc/ipa-sra.c
+++ b/gcc/ipa-sra.c
@@ -795,17 +795,17 @@ get_single_param_flow_source (const isra_param_flow *param_flow)
}
/* Inspect all uses of NAME and simple arithmetic calculations involving NAME
- in NODE and return a negative number if any of them is used for something
- else than either an actual call argument, simple arithmetic operation or
- debug statement. If there are no such uses, return the number of actual
- arguments that this parameter eventually feeds to (or zero if there is none).
- For any such parameter, mark PARM_NUM as one of its sources. ANALYZED is a
- bitmap that tracks which SSA names we have already started
- investigating. */
+ in FUN represented with NODE and return a negative number if any of them is
+ used for something else than either an actual call argument, simple
+ arithmetic operation or debug statement. If there are no such uses, return
+ the number of actual arguments that this parameter eventually feeds to (or
+ zero if there is none). For any such parameter, mark PARM_NUM as one of its
+ sources. ANALYZED is a bitmap that tracks which SSA names we have already
+ started investigating. */
static int
-isra_track_scalar_value_uses (cgraph_node *node, tree name, int parm_num,
- bitmap analyzed)
+isra_track_scalar_value_uses (function *fun, cgraph_node *node, tree name,
+ int parm_num, bitmap analyzed)
{
int res = 0;
imm_use_iterator imm_iter;
@@ -859,8 +859,9 @@ isra_track_scalar_value_uses (cgraph_node *node, tree name, int parm_num,
}
res += all_uses;
}
- else if ((is_gimple_assign (stmt) && !gimple_has_volatile_ops (stmt))
- || gimple_code (stmt) == GIMPLE_PHI)
+ else if (!stmt_unremovable_because_of_non_call_eh_p (fun, stmt)
+ && ((is_gimple_assign (stmt) && !gimple_has_volatile_ops (stmt))
+ || gimple_code (stmt) == GIMPLE_PHI))
{
tree lhs;
if (gimple_code (stmt) == GIMPLE_PHI)
@@ -876,7 +877,7 @@ isra_track_scalar_value_uses (cgraph_node *node, tree name, int parm_num,
gcc_assert (!gimple_vdef (stmt));
if (bitmap_set_bit (analyzed, SSA_NAME_VERSION (lhs)))
{
- int tmp = isra_track_scalar_value_uses (node, lhs, parm_num,
+ int tmp = isra_track_scalar_value_uses (fun, node, lhs, parm_num,
analyzed);
if (tmp < 0)
{
@@ -927,7 +928,8 @@ isra_track_scalar_param_local_uses (function *fun, cgraph_node *node, tree parm,
return true;
bitmap analyzed = BITMAP_ALLOC (NULL);
- int call_uses = isra_track_scalar_value_uses (node, name, parm_num, analyzed);
+ int call_uses = isra_track_scalar_value_uses (fun, node, name, parm_num,
+ analyzed);
BITMAP_FREE (analyzed);
if (call_uses < 0)
return true;
diff --git a/gcc/testsuite/gcc.dg/ipa/pr95113.c b/gcc/testsuite/gcc.dg/ipa/pr95113.c
new file mode 100644
index 00000000000..a8f8c901ebe
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/ipa/pr95113.c
@@ -0,0 +1,33 @@
+/* { dg-do run } */
+/* { dg-options "-O2 -fexceptions -fnon-call-exceptions" } */
+/* { dg-require-effective-target exceptions } */
+
+int a, b;
+
+static inline long int
+foo (long int x, int y)
+{
+ if (y == 0)
+ return 0;
+
+ if (x == -1 && y == -1)
+ return 0;
+
+ return x / y;
+}
+
+static inline int
+bar (int *p)
+{
+ int c = foo (a, 1) + *p;
+ return b;
+}
+
+int
+main ()
+{
+ int d = 0;
+ b = foo (1, 1);
+ bar (&d);
+ return 0;
+}
diff --git a/gcc/tree-eh.c b/gcc/tree-eh.c
index 10ef2e3157c..4246dca8806 100644
--- a/gcc/tree-eh.c
+++ b/gcc/tree-eh.c
@@ -2936,6 +2936,16 @@ stmt_could_throw_p (function *fun, gimple *stmt)
}
}
+/* Return true if STMT in function FUN must be assumed necessary because of
+ non-call exceptions. */
+
+bool
+stmt_unremovable_because_of_non_call_eh_p (function *fun, gimple *stmt)
+{
+ return (fun->can_throw_non_call_exceptions
+ && !fun->can_delete_dead_exceptions
+ && stmt_could_throw_p (fun, stmt));
+}
/* Return true if expression T could throw an exception. */
diff --git a/gcc/tree-eh.h b/gcc/tree-eh.h
index cb1019e0d87..ba911cadbe7 100644
--- a/gcc/tree-eh.h
+++ b/gcc/tree-eh.h
@@ -39,6 +39,7 @@ extern bool operation_could_trap_p (enum tree_code, bool, bool, tree);
extern bool tree_could_trap_p (tree);
extern tree rewrite_to_non_trapping_overflow (tree);
extern bool stmt_could_throw_p (function *, gimple *);
+extern bool stmt_unremovable_because_of_non_call_eh_p (function *, gimple *);
extern bool tree_could_throw_p (tree);
extern bool stmt_can_throw_external (function *, gimple *);
extern bool stmt_can_throw_internal (function *, gimple *);
diff --git a/gcc/tree-ssa-dce.c b/gcc/tree-ssa-dce.c
index 757cfad5b5e..fae5ae72340 100644
--- a/gcc/tree-ssa-dce.c
+++ b/gcc/tree-ssa-dce.c
@@ -201,9 +201,7 @@ mark_stmt_if_obviously_necessary (gimple *stmt, bool aggressive)
{
/* With non-call exceptions, we have to assume that all statements could
throw. If a statement could throw, it can be deemed necessary. */
- if (cfun->can_throw_non_call_exceptions
- && !cfun->can_delete_dead_exceptions
- && stmt_could_throw_p (cfun, stmt))
+ if (stmt_unremovable_because_of_non_call_eh_p (cfun, stmt))
{
mark_stmt_necessary (stmt, true);
return;
--
2.26.2
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