[PATCH]middle-end: skip checking loop exits if loop malformed [PR111878]

[Tamar Christina <tamar.christina@arm.com>]

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Hi All,

Before my refactoring if the loop->latch was incorrect then find_loop_location
skipped checking the edges and would eventually return a dummy location.

It turns out that a loop can have
loops_state_satisfies_p (LOOPS_HAVE_RECORDED_EXITS) but also not have a latch
in which case get_loop_exit_edges traps.

This restores the old behavior.

Bootstrapped Regtested on x86_64-pc-linux-gnu and no issues.

Ok for master?

Thanks,
Tamar

gcc/ChangeLog:

	PR tree-optimization/111878
	* tree-vect-loop-manip.cc (find_loop_location): Skip edges check if
	latch incorrect.

gcc/testsuite/ChangeLog:

	PR tree-optimization/111878
	* gcc.dg/graphite/pr111878.c: New test.

--- inline copy of patch -- 
diff --git a/gcc/testsuite/gcc.dg/graphite/pr111878.c b/gcc/testsuite/gcc.dg/graphite/pr111878.c
new file mode 100644
index 0000000000000000000000000000000000000000..6722910062e43c827e94c53b43f106af1848852a
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/graphite/pr111878.c
@@ -0,0 +1,19 @@
+/* { dg-options "-O3 -fgraphite-identity -fsave-optimization-record" } */
+
+int long_c2i_ltmp;
+int *long_c2i_cont;
+
+void
+long_c2i (long utmp, int i)
+{
+  int neg = 1;
+  switch (long_c2i_cont[0])
+    case 0:
+    neg = 0;
+  for (; i; i++)
+    if (neg)
+      utmp |= long_c2i_cont[i] ^ 5;
+    else
+      utmp |= long_c2i_cont[i];
+  long_c2i_ltmp = utmp;
+}
diff --git a/gcc/tree-vect-loop-manip.cc b/gcc/tree-vect-loop-manip.cc
index b9161274ce401a7307f3e61ad23aa036701190d7..ff188840c1762d0b5fb6655cb93b5a8662b31343 100644
--- a/gcc/tree-vect-loop-manip.cc
+++ b/gcc/tree-vect-loop-manip.cc
@@ -1792,7 +1792,8 @@ find_loop_location (class loop *loop)
   if (!loop)
     return dump_user_location_t ();
 
-  if (loops_state_satisfies_p (LOOPS_HAVE_RECORDED_EXITS))
+  if (loops_state_satisfies_p (LOOPS_HAVE_RECORDED_EXITS)
+      && loop->latch != EXIT_BLOCK_PTR_FOR_FN (cfun))
     {
       /* We only care about the loop location, so use any exit with location
 	 information.  */




-- 

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diff --git a/gcc/testsuite/gcc.dg/graphite/pr111878.c b/gcc/testsuite/gcc.dg/graphite/pr111878.c
new file mode 100644
index 0000000000000000000000000000000000000000..6722910062e43c827e94c53b43f106af1848852a
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/graphite/pr111878.c
@@ -0,0 +1,19 @@
+/* { dg-options "-O3 -fgraphite-identity -fsave-optimization-record" } */
+
+int long_c2i_ltmp;
+int *long_c2i_cont;
+
+void
+long_c2i (long utmp, int i)
+{
+  int neg = 1;
+  switch (long_c2i_cont[0])
+    case 0:
+    neg = 0;
+  for (; i; i++)
+    if (neg)
+      utmp |= long_c2i_cont[i] ^ 5;
+    else
+      utmp |= long_c2i_cont[i];
+  long_c2i_ltmp = utmp;
+}
diff --git a/gcc/tree-vect-loop-manip.cc b/gcc/tree-vect-loop-manip.cc
index b9161274ce401a7307f3e61ad23aa036701190d7..ff188840c1762d0b5fb6655cb93b5a8662b31343 100644
--- a/gcc/tree-vect-loop-manip.cc
+++ b/gcc/tree-vect-loop-manip.cc
@@ -1792,7 +1792,8 @@ find_loop_location (class loop *loop)
   if (!loop)
     return dump_user_location_t ();
 
-  if (loops_state_satisfies_p (LOOPS_HAVE_RECORDED_EXITS))
+  if (loops_state_satisfies_p (LOOPS_HAVE_RECORDED_EXITS)
+      && loop->latch != EXIT_BLOCK_PTR_FOR_FN (cfun))
     {
       /* We only care about the loop location, so use any exit with location
 	 information.  */