-finline-stringops: allow expansion into edges [PR113002]

Builtin expanders for memset and memcpy may involve conditionals and
loops, but their sequences may be end up emitted in edges.  Alas,
commit_one_edge_insertion rejects sequences that end with a jump, a
requirement that makes sense for insertions after expand, but not so
much during expand.

During expand, jumps may appear in the middle of the insert sequence
as much as in the end, and it's only after committing edge insertions
out of PHI nodes that we go through the entire function splitting
blocks where needed, so relax the assert in commit_one_edge_insertion
so that jumps are accepted during expand even at the end of the
sequence.


for  gcc/ChangeLog

	PR rtl-optimization/113002
	* cfgrtl.cc (commit_one_edge_insertion): Tolerate jumps in the
	inserted sequence during expand.

for  gcc/testsuite/ChangeLog

	PR rtl-optimization/113002
	* gcc.dg/vect/pr113002.c: New.

2 files changed, 20 insertions, 1 deletions

diff --git a/gcc/cfgrtl.cc b/gcc/cfgrtl.cc
index 2a3f853..437eb3a 100644
--- a/gcc/cfgrtl.cc
+++ b/gcc/cfgrtl.cc
@@ -2092,7 +2092,13 @@ commit_one_edge_insertion (edge e)
 	delete_insn (before);
     }
   else
-    gcc_assert (!JUMP_P (last));
+    /* Some builtin expanders, such as those for memset and memcpy,
+       may generate loops and conditionals, and those may get emitted
+       into edges.  That's ok while expanding to rtl, basic block
+       boundaries will be identified and split afterwards.  ???  Need
+       we check whether the destination labels of any inserted jumps
+       are also part of the inserted sequence?  */
+    gcc_assert (!JUMP_P (last) || currently_expanding_to_rtl);
 }
 
 /* Update the CFG for all queued instructions.  */
diff --git a/gcc/testsuite/gcc.dg/vect/pr113002.c b/gcc/testsuite/gcc.dg/vect/pr113002.c
new file mode 100644
index 0000000..186710f
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/vect/pr113002.c
@@ -0,0 +1,13 @@
+/* { dg-do compile } */
+/* { dg-require-effective-target int128 } */
+/* { dg-options "-finline-stringops -Os" } */
+
+typedef __int128 v64u128 __attribute__((vector_size(64)));
+int c;
+v64u128 u;
+void foo() {
+  if (c)
+    u = (v64u128){0};
+  else
+    u = (v64u128){1};
+}