middle-end: Fix malloc like functions when calling with void "return" [PR120024]

When expanding malloc like functions, we copy the return register into a temporary
and then mark that temporary register with a noalias regnote and the alignment.
This works fine unless you are calling the function with a return type of void.
At this point then the valreg will be null and a crash will happen.

A few cleanups are included in this patch because it was easier to do the fix
with the cleanups added.
The start_sequence/end_sequence for ECF_MALLOC is no longer needed; I can't tell
if it was ever needed.
The emit_move_insn function returns the last emitted instruction anyways so
there is no reason to call get_last_insn as we can just use the return value
of emit_move_insn. This has been true since this code was originally added
so I don't understand why it was done that way beforehand.

Bootstrapped and tested on x86_64-linux-gnu.

	PR middle-end/120024

gcc/ChangeLog:

	* calls.cc (expand_call): Remove start_sequence/end_sequence
	for ECF_MALLOC.
	Check valreg before deferencing it when it comes to malloc like
	functions. Use the return value of emit_move_insn instead of
	calling get_last_insn.

gcc/testsuite/ChangeLog:

	* gcc.dg/torture/malloc-1.c: New test.
	* gcc.dg/torture/malloc-2.c: New test.

Signed-off-by: Andrew Pinski <andrew.pinski@oss.qualcomm.com>

2 files changed, 22 insertions, 0 deletions

diff --git a/gcc/testsuite/gcc.dg/torture/malloc-1.c b/gcc/testsuite/gcc.dg/torture/malloc-1.c
new file mode 100644
index 0000000..ba24153
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/malloc-1.c
@@ -0,0 +1,10 @@
+/* { dg-do compile } */
+/* PR middle-end/120024 */
+
+void *f(unsigned) __attribute__((malloc));
+void g()
+{
+  void *(*g)(unsigned) = f;
+  void (*h)(unsigned) = (void (*)(unsigned))g;
+  h(1);
+}
diff --git a/gcc/testsuite/gcc.dg/torture/malloc-2.c b/gcc/testsuite/gcc.dg/torture/malloc-2.c
new file mode 100644
index 0000000..8eeca9d
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/malloc-2.c
@@ -0,0 +1,12 @@
+/* { dg-do compile } */
+/* PR middle-end/120024 */
+
+void *f(unsigned) __attribute__((malloc));
+void h1(void);
+void g(void)
+{
+  void *(*g)(unsigned) = f;
+  void (*h)(unsigned) = (void (*)(unsigned))g;
+  h(1);
+  h1();
+}