[gcc r11-8202] PR middle-end/89230 - Bogus uninited usage warning with printf

[Martin Sebor <msebor@gcc.gnu.org>]

https://gcc.gnu.org/g:2dbbbe893f75f587c48111ab4c97cf5e74fb91bb

commit r11-8202-g2dbbbe893f75f587c48111ab4c97cf5e74fb91bb
Author: Martin Sebor <msebor@redhat.com>
Date:   Thu Apr 15 14:09:56 2021 -0600

    PR middle-end/89230 - Bogus uninited usage warning with printf
    
    gcc/testsuite/ChangeLog:
            * gcc.dg/uninit-pr89230-1.c: New test.
            * gcc.dg/uninit-pr89230-2.c: Same.

Diff:
---
 gcc/testsuite/gcc.dg/uninit-pr89230-1.c | 25 +++++++++++++++
 gcc/testsuite/gcc.dg/uninit-pr89230-2.c | 54 +++++++++++++++++++++++++++++++++
 2 files changed, 79 insertions(+)

diff --git a/gcc/testsuite/gcc.dg/uninit-pr89230-1.c b/gcc/testsuite/gcc.dg/uninit-pr89230-1.c
new file mode 100644
index 00000000000..1c07c4f6d78
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/uninit-pr89230-1.c
@@ -0,0 +1,25 @@
+/* PR middle-end/89230 - Bogus uninited usage warning with printf
+   { dg-do compile }
+   { dg-options "-O2 -Wall" } */
+
+struct S { int i, j; };
+
+/* attribute__ ((malloc)) */ struct S* f (void);
+
+int g (void)
+{
+  struct S *p = f (), *q;
+
+  if (p->i || !(q = f ()) || p->j != q->i)
+   {
+     __builtin_printf ("%i", p->i);
+
+     if (p->i)
+       return 1;
+
+     if (!q)        // { dg-bogus "\\\[-Wmaybe-uninitialized" }
+       return 2;
+   }
+
+  return 0;
+}
diff --git a/gcc/testsuite/gcc.dg/uninit-pr89230-2.c b/gcc/testsuite/gcc.dg/uninit-pr89230-2.c
new file mode 100644
index 00000000000..473d2da5d3d
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/uninit-pr89230-2.c
@@ -0,0 +1,54 @@
+/* PR middle-end/89230 - Bogus uninited usage warning with printf
+   { dg-do compile }
+   { dg-options "-O2 -Wall" } */
+
+typedef __SIZE_TYPE__ size_t;
+
+extern void* memset (void*, int, size_t);
+extern int printf (const char*, ...);
+extern int rand (void);
+
+struct S
+{
+  int a;
+  int b;
+};
+
+struct H
+{
+  int c;
+  int d;
+};
+
+void getblk (void* blk)
+{
+  struct S* s = (struct S*) blk;
+  memset (blk, 0, 512);
+  s->a = rand () & 1;
+}
+
+struct H* gethdr (void* blk)
+{
+  memset (blk, 0, 512);
+  return rand () & 1 ? (struct H*) blk : 0;
+}
+
+int main (void)
+{
+  char blk[512], tmp[512];
+  struct S *s = (struct S*) blk;
+  struct H *h;
+
+  getblk (blk);
+
+  if (s->a  ||  !(h = gethdr (tmp))  ||  s->a != h->d) {
+
+    printf ("%d\n", s->b);
+    if (s->a)
+      printf ("s->a = %d\n", s->a);
+    else if (!h)
+      printf ("!h\n");
+    else
+      printf ("h->d = %d\n", h->d);
+  }
+}