On 1/18/22 13:06, Martin Sebor wrote:
On 1/18/22 06:37, Richard Sandiford wrote:
In this PR the waccess pass was fed:
D.10779 ={v} {CLOBBER};
VIEW_CONVERT_EXPR<svuint64_t[2]>(D.10779) = .MASK_LOAD_LANES
(addr_5(D), 64B, _2);
_7 = D.10779.__val[0];
However, the tracking of m_clobbers only looked at gassigns,
so it missed that the clobber on the first line was overwritten
by the call on the second line.
This patch splits the updating of m_clobbers out into its own
function, called after the check_*() routines, and extends it
to handle both gassigns and gcalls. I think that makes sense
as an instance of the "read, operate, write" model, with the
new function being part of "write".
Previously only the gimple_clobber_p handling was conditional
on m_check_dangling_p, but I think the whole of the new function
can be. We only enter stmts into m_clobbers if m_check_dangling_p,
so we only need to remove them under the same condition.
Thanks for the patch. If you or someone can think of a test case
that's independent of a target, adding one would be very helpful.
Other than that, since I can't approve any changes I CC Jason who
was kind enough to approve the implementation of the warning for
his OK.
OK if Martin is happy with it.
Tested on aarch64-linux-gnu. OK to install?
Richard
gcc/
PR middle-end/104092
* gimple-ssa-warn-access.cc (pass_waccess::update_clobbers_from_lhs):
New function, split out from...
(pass_waccess::check_stmt): ...here and generalized to calls.
(pass_waccess::check_block): Call it.
gcc/testsuite/
* gcc.target/aarch64/sve/acle/general/pr104092.c: New test.
---
gcc/gimple-ssa-warn-access.cc | 68 +++++++++++--------
.../aarch64/sve/acle/general/pr104092.c | 7 ++
2 files changed, 48 insertions(+), 27 deletions(-)
create mode 100644
gcc/testsuite/gcc.target/aarch64/sve/acle/general/pr104092.c
diff --git a/gcc/gimple-ssa-warn-access.cc
b/gcc/gimple-ssa-warn-access.cc
index f639807a78a..25066fa6b89 100644
--- a/gcc/gimple-ssa-warn-access.cc
+++ b/gcc/gimple-ssa-warn-access.cc
@@ -2094,6 +2094,9 @@ private:
/* Check a non-call statement. */
void check_stmt (gimple *);
+ /* Update the clobber map based on the lhs of a statement. */
+ void update_clobbers_from_lhs (gimple *);
+
/* Check statements in a basic block. */
void check_block (basic_block);
@@ -4270,33 +4273,6 @@ is_auto_decl (tree x)
void
pass_waccess::check_stmt (gimple *stmt)
{
- if (m_check_dangling_p && gimple_clobber_p (stmt))
- {
- /* Ignore clobber statemts in blocks with exceptional edges. */
- basic_block bb = gimple_bb (stmt);
- edge e = EDGE_PRED (bb, 0);
- if (e->flags & EDGE_EH)
- return;
-
- tree var = gimple_assign_lhs (stmt);
- m_clobbers.put (var, stmt);
- return;
- }
-
- if (is_gimple_assign (stmt))
- {
- /* Clobbered unnamed temporaries such as compound literals can be
- revived. Check for an assignment to one and remove it from
- M_CLOBBERS. */
- tree lhs = gimple_assign_lhs (stmt);
- while (handled_component_p (lhs))
- lhs = TREE_OPERAND (lhs, 0);
-
- if (is_auto_decl (lhs))
- m_clobbers.remove (lhs);
- return;
- }
-
if (greturn *ret = dyn_cast <greturn *> (stmt))
{
if (optimize && flag_isolate_erroneous_paths_dereference)
@@ -4326,6 +4302,42 @@ pass_waccess::check_stmt (gimple *stmt)
}
}
+/* Update the clobber map based on the lhs of STMT. */
+
+void
+pass_waccess::update_clobbers_from_lhs (gimple *stmt)
+{
+ if (gimple_clobber_p (stmt))
+ {
+ /* Ignore clobber statements in blocks with exceptional edges. */
+ basic_block bb = gimple_bb (stmt);
+ edge e = EDGE_PRED (bb, 0);
+ if (e->flags & EDGE_EH)
+ return;
+
+ tree var = gimple_assign_lhs (stmt);
+ m_clobbers.put (var, stmt);
+ return;
+ }
+
+ if (is_gimple_assign (stmt) || is_gimple_call (stmt))
+ {
+ /* Clobbered unnamed temporaries such as compound literals can be
+ revived. Check for an assignment to one and remove it from
+ M_CLOBBERS. */
+ tree lhs = gimple_get_lhs (stmt);
+ if (!lhs)
+ return;
+
+ while (handled_component_p (lhs))
+ lhs = TREE_OPERAND (lhs, 0);
+
+ if (is_auto_decl (lhs))
+ m_clobbers.remove (lhs);
+ return;
+ }
+}
+
/* Check basic block BB for invalid accesses. */
void
@@ -4340,6 +4352,8 @@ pass_waccess::check_block (basic_block bb)
check_call (call);
else
check_stmt (stmt);
+ if (m_check_dangling_p)
+ update_clobbers_from_lhs (stmt);
}
}
diff --git
a/gcc/testsuite/gcc.target/aarch64/sve/acle/general/pr104092.c
b/gcc/testsuite/gcc.target/aarch64/sve/acle/general/pr104092.c
new file mode 100644
index 00000000000..c17ece7d82f
--- /dev/null
+++ b/gcc/testsuite/gcc.target/aarch64/sve/acle/general/pr104092.c
@@ -0,0 +1,7 @@
+/* { dg-options "-O2 -Wall" } */
+
+#include <arm_sve.h>
+
+svuint64_t bar(svbool_t pg, const uint64_t *addr) {
+ return svget2(svld2_u64(pg, addr), 0);
+}
