Hi!
The following bug has been introduced when cond_expr_object_size has been
added in 2007. We want to treat a COND_EXPR like a PHI with 2 arguments,
and PHI is handled in a loop that breaks if the lhs value is unknown, and
then does the if (TREE_CODE (arg) == SSA_NAME) merge_object_sizes else
expr_object_size which is used even in places that handle just a single
operand (with the lhs value initialized to the opposite value of unknown
first). At least expr_object_size asserts that the lhs value is not
unknown at the start.
Fixed thusly, bootstrapped/regtested on x86_64-linux and i686-linux, ok for
trunk?
2019-10-17 Jakub Jelinek <ja...@redhat.com>
PR tree-optimization/92056
* tree-object-size.c (cond_expr_object_size): Return early if then_
processing resulted in unknown size.
* gcc.c-torture/compile/pr92056.c: New test.
--- gcc/tree-object-size.c.jj 2019-10-05 09:35:14.895967464 +0200
+++ gcc/tree-object-size.c 2019-10-16 15:34:11.414769994 +0200
@@ -903,6 +903,9 @@ cond_expr_object_size (struct object_siz
else
expr_object_size (osi, var, then_);
+ if (object_sizes[object_size_type][varno] == unknown[object_size_type])
+ return reexamine;
+
if (TREE_CODE (else_) == SSA_NAME)
reexamine |= merge_object_sizes (osi, var, else_, 0);
else
--- gcc/testsuite/gcc.c-torture/compile/pr92056.c.jj 2019-10-16
15:42:56.042848440 +0200
+++ gcc/testsuite/gcc.c-torture/compile/pr92056.c 2019-10-16
15:42:41.595066602 +0200
@@ -0,0 +1,18 @@
+/* PR tree-optimization/92056 */
+
+const char *d;
+
+void
+foo (int c, char *e, const char *a, const char *b)
+{
+ switch (c)
+ {
+ case 33:
+ for (;; d++)
+ if (__builtin_strcmp (b ? : "", d))
+ return;
+ break;
+ case 4:
+ __builtin_sprintf (e, a);
+ }
+}
Jakub
