The following makes sure the virtual operand updating when sinking
stores works for the case we ignore paths to kills. The final
sink location might not post-dominate the original stmt location
which would require inserting of a virtual PHI which we do not support.
Bootstrapped and tested on x86_64-unknown-linux-gnu, pushed.
PR tree-optimization/115220
PR tree-optimization/115226
* tree-ssa-sink.cc (statement_sink_location): When ignoring
paths to kills when sinking stores make sure the final
sink location is still post-dominated by the original one.
Otherwise we'd need to insert a PHI node to merge virtual operands.
* gcc.dg/torture/pr115220.c: New testcase.
* gcc.dg/torture/pr115226.c: New testcase.
---
gcc/testsuite/gcc.dg/torture/pr115220.c | 14 ++++++++++++++
gcc/testsuite/gcc.dg/torture/pr115226.c | 15 +++++++++++++++
gcc/tree-ssa-sink.cc | 12 +++++++++---
3 files changed, 38 insertions(+), 3 deletions(-)
create mode 100644 gcc/testsuite/gcc.dg/torture/pr115220.c
create mode 100644 gcc/testsuite/gcc.dg/torture/pr115226.c
diff --git a/gcc/testsuite/gcc.dg/torture/pr115220.c
b/gcc/testsuite/gcc.dg/torture/pr115220.c
new file mode 100644
index 00000000000..e7b5da6ba42
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr115220.c
@@ -0,0 +1,14 @@
+/* { dg-do compile } */
+/* { dg-additional-options "--param logical-op-non-short-circuit=0" } */
+
+extern char **environ;
+static char ***p_environ = &environ;
+int
+_setenv_r (const char *name, const char *value)
+{
+ register char *C;
+ int offset;
+ for (C = (*p_environ)[offset]; (*C = *name++) && *C != '='; ++C);
+ for (*C++ = '='; (*C++ = *value++) != 0;);
+ return 0;
+}
diff --git a/gcc/testsuite/gcc.dg/torture/pr115226.c
b/gcc/testsuite/gcc.dg/torture/pr115226.c
new file mode 100644
index 00000000000..9a0bc7c9b6a
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr115226.c
@@ -0,0 +1,15 @@
+/* { dg-do compile } */
+
+extern void c();
+int a, b;
+int main() {
+ while (b) {
+ int d, e = 0, *f = &a;
+ *f = 1;
+ e = 1 >> d ? : 1 << d;
+ if (e)
+ a = 0;
+ c();
+ }
+ return 0;
+}
diff --git a/gcc/tree-ssa-sink.cc b/gcc/tree-ssa-sink.cc
index b0fe871cf1e..8c551e42a4d 100644
--- a/gcc/tree-ssa-sink.cc
+++ b/gcc/tree-ssa-sink.cc
@@ -467,11 +467,17 @@ statement_sink_location (gimple *stmt, basic_block frombb,
if (!sinkbb)
return false;
- sinkbb = select_best_block (frombb, sinkbb, stmt);
- if (sinkbb == frombb)
+ basic_block bestbb = select_best_block (frombb, sinkbb, stmt);
+ if (bestbb == frombb
+ /* When we sink a store make sure there's not a path to any of
+ the possibly skipped killing defs as that wrecks the virtual
+ operand update, requiring inserting of a PHI node. */
+ || (gimple_vdef (stmt)
+ && bestbb != sinkbb
+ && !dominated_by_p (CDI_POST_DOMINATORS, bestbb, sinkbb)))
return false;
- *togsi = gsi_after_labels (sinkbb);
+ *togsi = gsi_after_labels (bestbb);
return true;
}
--
2.35.3
