predicate aware uninitialized analysis

From-SVN: r158835

gcc/ChangeLog

@@ -1,3 +1,49 @@
+2010-04-28  Xinliang David Li  <davidxl@google.com>
+
+	PR c/42643
+	* tree-ssa-uninit.c (can_skip_redundant_opnd): New function.
+	(compute_uninit_opnds_pos): New function.
+	(is_non_loop_exit_postdominating): New function.
+	(compute_control_dep_chain): New function.
+	(find_pdom): New function.
+	(convert_control_dep_chain_into_preds): New function.
+	(find_predicates): New function.
+	(find_control_equiv_block): New function.
+	(collect_phi_def_edges): New function.
+	(find_def_preds): New function.
+	(find_dom): New function.
+	(dump_predicates): New function.
+	(get_cmp_code): New function.
+	(is_value_included_in): New function.
+	(find_matching_predicate_in_rest_chains): New function.
+	(use_pred_not_overlap_with_undef_path_pred): New function.
+	(is_use_properly_guarded): New function.
+	(normalize_cond_1): New function.
+	(is_and_or_or): New function.
+	(normalize_cond): New function.
+	(is_gcond_subset_of): New function.
+	(is_subset_of_any): New function.
+	(is_or_set_subset_of): New function.
+	(is_and_set_subset_of): New function.
+	(is_norm_cond_subset_of): New function.
+	(is_pred_expr_subset_of): New function.
+	(is_pred_chain_subset_of): New function.
+	(is_included_in): New function.
+	(is_superset_of): New function.
+	(find_uninit_use): New function.
+	(warn_uninitialized_phi): New function.
+	(compute_possibly_undefined_names): New function.
+	(ssa_undefined_value_p): New function.
+	(execute_late_warn_uninitialized): New function.
+	* tree-ssa.c (ssa_undefined_value_p): Removed.
+	(warn_uninit): Changed to extern.
+	(warn_uninitialized_phi): Removed.
+	(warn_uninitialized_vars): Changed to extern.
+	(execute_late_warn_uninitialized): Removed
+	* tree-flow.h: Add new prototypes.
+	* timevar.def: Add new time variable.
+	* Makefile.in: Add new build file.
+
 2010-04-28  Uros Bizjak  <ubizjak@gmail.com>
 
 	* config/alpha/elf.h (ASM_DECLARE_OBJECT_NAME): Use gnu_unique_object

gcc/Makefile.in

@@ -1385,6 +1385,7 @@ OBJS-common = \
 	tree-ssa-threadedge.o \
 	tree-ssa-threadupdate.o \
 	tree-ssa-uncprop.o \
+	tree-ssa-uninit.o \
 	tree-ssa.o \
 	tree-ssanames.o \
 	tree-stdarg.o \
@@ -2288,6 +2289,12 @@ tree-ssa-structalias.o: tree-ssa-structalias.c \
    $(GIMPLE_H) $(HASHTAB_H) $(FUNCTION_H) $(CGRAPH_H) \
    $(TREE_PASS_H) $(TIMEVAR_H) alloc-pool.h $(SPLAY_TREE_H) $(PARAMS_H) \
    gt-tree-ssa-structalias.h $(CGRAPH_H) $(ALIAS_H) pointer-set.h
+tree-ssa-uninit.o : tree-ssa-uninit.c $(TREE_FLOW_H) $(CONFIG_H) $(SYSTEM_H) \
+   $(RTL_H) $(TREE_H) $(TM_P_H) $(EXPR_H) output.h $(DIAGNOSTIC_H) \
+   $(TOPLEV_H) $(FUNCTION_H) $(TIMEVAR_H) $(TM_H) coretypes.h \
+   $(TREE_DUMP_H) langhooks.h tree-pass.h $(BASIC_BLOCK_H) $(BITMAP_H) \
+   $(FLAGS_H) $(GGC_H) hard-reg-set.h $(HASHTAB_H) pointer-set.h \
+   $(GIMPLE_H) $(TREE_INLINE_H) $(VARRAY_H)
 tree-ssa.o : tree-ssa.c $(TREE_FLOW_H) $(CONFIG_H) $(SYSTEM_H) \
    $(RTL_H) $(TREE_H) $(TM_P_H) $(EXPR_H) output.h $(DIAGNOSTIC_H) \
    $(TOPLEV_H) $(FUNCTION_H) $(TIMEVAR_H) $(TM_H) coretypes.h \

gcc/testsuite/ChangeLog

@@ -1,3 +1,39 @@
+2010-04-28  Xinliang David Li  <davidxl@google.com>
+
+	* gcc.dg/uninit-pred-2_b.c: New test.
+	* gcc.dg/uninit-pred-4_b.c: New test.
+	* gcc.dg/uninit-pred-3_d.c: New test.
+	* gcc.dg/uninit-pred-6_b.c: New test.
+	* gcc.dg/uninit-pred-8_b.c: New test.
+	* gcc.dg/uninit-pred-3_a.c: New test.
+	* gcc.dg/uninit-pred-2_c.c: New test.
+	* gcc.dg/uninit-pred-5_a.c: New test.
+	* gcc.dg/uninit-pred-3_e.c: New test.
+	* gcc.dg/uninit-pred-7_a.c: New test.
+	* gcc.dg/uninit-pred-6_c.c: New test.
+	* gcc.dg/uninit-pred-9_a.c: New test.
+	* gcc.dg/uninit-pred-8_c.c: New test.
+	* gcc.dg/uninit-pred-3_b.c: New test.
+	* gcc.dg/uninit-pred-5_b.c: New test.
+	* gcc.dg/uninit-pred-7_b.c: New test.
+	* gcc.dg/uninit-pred-6_d.c: New test.
+	* gcc.dg/uninit-pred-9_b.c: New test.
+	* gcc.dg/uninit-pred-2_a.c: New test.
+	* gcc.dg/uninit-pred-4_a.c: New test.
+	* gcc.dg/uninit-pred-3_c.c: New test.
+	* gcc.dg/uninit-pred-6_a.c: New test.
+	* gcc.dg/uninit-pred-8_a.c: New test.
+	* gcc.dg/uninit-pred-7_c.c: New test.
+	* gcc.dg/uninit-pred-6_e.c: New test.
+	* g++.dg/uninit-pred-loop-1_b.cc: New test.
+	* g++.dg/uninit-pred-1_a.C: New test.
+	* g++.dg/uninit-pred-1_b.C: New test.
+	* g++.dg/uninit-pred-2_a.C: New test.
+	* g++.dg/uninit-pred-2_b.C: New test.
+	* g++.dg/uninit-pred-loop-1_a.cc: New test.
+	* g++.dg/uninit-pred-loop-1_c.cc: New test.
+	* g++.dg/uninit-pred-loop_1.cc: New test.
+
 2010-04-28  Martin Jambor  <mjambor@suse.cz>
 
 	* gcc.dg/lto/20091209-1_0.c: New testcase.

gcc/testsuite/g++.dg/uninit-pred-1_a.C

@@ -0,0 +1,63 @@
+/* { dg-do compile } */
+/* { dg-options "-Wuninitialized -O2" } */
+
+typedef long long int64;
+void incr ();
+bool is_valid (int);
+int  get_time ();
+
+class A 
+{
+public:
+  A ();
+  ~A () {
+    if (I) delete I;
+  }
+
+private:
+  int* I;
+};
+
+bool get_url (A *);
+
+class M {
+
+ public:
+__attribute__ ((always_inline))  int GetC (int *c)  {
+
+    A details_str;
+    if (!get_url (&details_str))
+      {
+        incr ();
+        return 1;
+      }
+
+    *c = get_time ();
+    return -1;
+  }
+
+  void do_sth();
+  void do_sth2();
+   
+  void P (int64 t)
+    {
+      int cc; /* { dg-bogus "uninitialized" "uninitialized variable warning" }  */ 
+      if (GetC (&cc) >= 0 )
+        return;
+      
+      if (t && cc <= 0 )  /* { dg-bogus "uninitialized" "uninitialized variable warning" } */
+        {
+          this->do_sth();
+          return;
+        }
+
+    do_sth2();
+  }
+};
+
+M* m; 
+void foo(int x)
+{
+  m = new M;
+  m->P(x);
+}

gcc/testsuite/g++.dg/uninit-pred-1_b.C

@@ -0,0 +1,63 @@
+/* { dg-do compile } */
+/* { dg-options "-Wuninitialized -O2" } */
+
+typedef long long int64;
+void incr ();
+bool is_valid (int);
+int  get_time ();
+
+class A 
+{
+public:
+  A ();
+  ~A () {
+    if (I) delete I;
+  }
+
+private:
+  int* I;
+};
+
+bool get_url (A *);
+
+class M {
+
+ public:
+__attribute__ ((always_inline))  int GetC (int *c)  {
+
+    A details_str;
+    if (!get_url (&details_str))
+      {
+        incr ();
+        return 1;
+      }
+
+    *c = get_time ();
+    return -1;
+  }
+
+  void do_sth();
+  void do_sth2();
+   
+  void P (int64 t)
+    {
+      int cc; /* { dg-excess-errors "note: 'cc' was declared here" } */
+      if (GetC (&cc) <= 0 ) /* return flag checked wrongly */
+        return;
+      
+      if (t && cc <= 0 )  /* { dg-warning "uninitialized" "uninitialized variable warning" } */
+        {
+          this->do_sth();
+          return;
+        }
+
+    do_sth2();
+  }
+};
+
+M* m; 
+void foo(int x)
+{
+  m = new M;
+  m->P(x);
+}

gcc/testsuite/g++.dg/uninit-pred-2_a.C

@@ -0,0 +1,62 @@
+/* { dg-do compile } */
+/* { dg-options "-Wuninitialized -O2" } */
+
+typedef long long int64;
+void incr ();
+bool is_valid (int);
+int  get_time ();
+
+class A 
+{
+public:
+  A ();
+  ~A () {
+    if (I) delete I;
+  }
+
+private:
+  int* I;
+};
+
+bool get_url (A *);
+
+class M {
+
+ public:
+__attribute__ ((always_inline))  bool GetC (int *c)  {
+
+    A details_str;
+    if (get_url (&details_str))
+      {
+        *c = get_time ();
+        return true;
+      }
+
+    return false;
+  }
+
+  void do_sth();
+  void do_sth2();
+   
+  void P (int64 t)
+    {
+      int cc; 
+      if (!GetC (&cc)) /* return flag checked properly */
+        return;
+      
+      if (cc <= 0)  /* { dg-bogus "uninitialized" "uninitialized variable warning" } */
+        {
+          this->do_sth();
+          return;
+        }
+
+    do_sth2();
+  }
+};
+
+M* m; 
+void foo(int x)
+{
+  m = new M;
+  m->P(x);
+}

gcc/testsuite/g++.dg/uninit-pred-2_b.C

@@ -0,0 +1,62 @@
+/* { dg-do compile } */
+/* { dg-options "-Wuninitialized -O2" } */
+
+typedef long long int64;
+void incr ();
+bool is_valid (int);
+int  get_time ();
+
+class A 
+{
+public:
+  A ();
+  ~A () {
+    if (I) delete I;
+  }
+
+private:
+  int* I;
+};
+
+bool get_url (A *);
+
+class M {
+
+ public:
+__attribute__ ((always_inline))  bool GetC (int *c)  {
+
+    A details_str;
+    if (get_url (&details_str))
+      {
+        *c = get_time ();
+        return true;
+      }
+
+    return false;
+  }
+
+  void do_sth();
+  void do_sth2();
+   
+  void P (int64 t)
+    {
+      int cc; /* { dg-excess-errors "note" } */
+      if (GetC (&cc)) /* return flag checked wrongly */
+        return;
+      
+      if (cc <= 0)  /* { dg-warning "uninitialized" "uninitialized variable warning" } */
+        {
+          this->do_sth();
+          return;
+        }
+
+    do_sth2();
+  }
+};
+
+M* m; 
+void foo(int x)
+{
+  m = new M;
+  m->P(x);
+}

gcc/testsuite/g++.dg/uninit-pred-loop-1_a.cc

@@ -0,0 +1,21 @@
+/* { dg-do compile } */
+/* { dg-options "-Wuninitialized -O2" } */
+
+extern int bar();
+int foo(void)
+{
+ for (;;) {
+   int err = ({int _err; /*  { dg-bogus "uninitialized" "false warning" } */
+     for (int i = 0; i < 16; ++i) {
+       _err = 17;
+       _err = bar();
+     }
+     _err; /*  { dg-bogus "uninitialized" "false warning" } */
+   });
+
+   if (err == 0) return 17; 
+ }
+
+ return 18;
+}
+

gcc/testsuite/g++.dg/uninit-pred-loop-1_b.cc

@@ -0,0 +1,21 @@
+/* { dg-do compile } */
+/* { dg-options "-Wuninitialized -O2" } */
+
+extern int bar();
+int foo(int n)
+{
+ for (;;) {
+   int err = ({int _err; 
+     for (int i = 0; i < n; ++i) {
+       _err = 17;
+       _err = bar();
+     }
+     _err; 
+   }); /* { dg-warning "uninitialized" "warn on _err" } */
+
+   if (err == 0) return 17; 
+ }
+
+ return 18;
+}
+

gcc/testsuite/g++.dg/uninit-pred-loop-1_c.cc

@@ -0,0 +1,23 @@
+/* { dg-do compile } */
+/* { dg-options "-Wuninitialized -O2" } */
+
+extern int bar();
+int foo(int n, int m)
+{
+ for (;;) {
+   int err = ({int _err; 
+     for (int i = 0; i < 16; ++i) {
+       if (m+i > n)
+          break;
+       _err = 17;
+       _err = bar();
+     }
+     _err; 
+   }); 
+
+   if (err == 0) return 17; }); /* { dg-warning "uninitialized" "warn on _err" } */
+ }
+
+ return 18;
+}
+

gcc/testsuite/g++.dg/uninit-pred-loop_1.cc

@@ -0,0 +1,21 @@
+/* { dg-do compile } */
+/* { dg-options "-Wuninitialized -O2" } */
+
+extern int bar();
+int foo(void)
+{
+ for (;;) {
+   int err = ({int _err; /*  { dg-bogus "uninitialized" "false warning" } */
+     for (int i = 0; i < 16; ++i) {
+       _err = 17;
+       _err = bar();
+     }
+     _err; /*  { dg-bogus "uninitialized" "false warning" } */
+   });
+
+   if (err == 0) return 17; 
+ }
+
+ return 18;
+}
+

gcc/testsuite/gcc.dg/uninit-11.c

@@ -17,10 +17,10 @@ void f2(void)
 
 void f3(int p)
 {
-  int x;		/* { dg-warning "may be used" "conditional" } */
+  int x;		
   if (p)
     x = p;
-  sink = x;
+  sink = x;            /* { dg-warning "may be used" "conditional" } */
 }
 
 void f4(int p)

gcc/testsuite/gcc.dg/uninit-5.c

@@ -1,7 +1,7 @@
 /* Spurious uninitialized-variable warnings.  */
-
+/* Disable jump threading, etc to test compiler analysis.  */
 /* { dg-do compile } */
-/* { dg-options "-O -Wuninitialized" } */
+/* { dg-options "-O -Wuninitialized -fno-tree-dce -fno-tree-vrp -fno-tree-dominator-opts" } */
 
 extern void use(int);
 extern void foo(void);

gcc/testsuite/gcc.dg/uninit-pred-2_a.c

@@ -0,0 +1,28 @@
+/* { dg-do compile } */
+/* { dg-options "-Wuninitialized -O2" } */
+
+int g;
+void bar (void);
+void blah (int);
+
+int foo (int n, int m, int r)
+{
+  int flag = 0;
+  int v;
+
+  if (n)
+    {
+      v = r;
+      flag = 1;
+    }
+
+  if (m)
+    g++;
+  else 
+    bar();
+
+  if (flag)
+    blah(v); /* { dg-bogus "uninitialized" "bogus uninitialized var warning" } */ 
+
+  return 0;
+}

gcc/testsuite/gcc.dg/uninit-pred-2_b.c

@@ -0,0 +1,29 @@
+/* { dg-do compile } */
+/* { dg-options "-Wuninitialized -O2" } */
+
+int g;
+void bar (void);
+void blah (int);
+
+int foo (int n, int m, int r)
+{
+  int flag = 0;
+  int v; 
+
+  if (n)
+    {
+      v = r;
+      flag = 1;
+    }
+
+  if (m)
+    g++;
+  else 
+    bar();
+
+  /* Wrong guard */
+  if (!flag)
+    blah(v); /* { dg-warning "uninitialized" "real uninitialized var warning" } */
+
+  return 0;
+}

gcc/testsuite/gcc.dg/uninit-pred-2_c.c

@@ -0,0 +1,48 @@
+/* { dg-do compile } */
+/* { dg-options "-Wuninitialized -O2" } */
+
+int g;
+void bar (void);
+void blah (int);
+
+int foo (int n, int m, int r)
+{
+  int flag = 0;
+  int v; 
+
+  if (n)
+    {
+      v = r;
+      flag = 1;
+    }
+
+  if (m) g++;
+  else bar();
+
+  if (flag)
+    blah(v); /* { dg-bogus "uninitialized" "bogus uninitialized var warning" } */ 
+
+  return 0;
+}
+
+int foo_2 (int n, int m, int r)
+{
+  int flag = 0;
+  int v; 
+
+  if (n)
+    {
+      v = r;
+      flag = 1;
+    }
+
+  if (m) g++;
+  else bar();
+
+  if (flag)
+    blah(v); /* { dg-bogus "uninitialized" "bogus uninitialized var warning" } */ 
+  else
+    blah(v); /* { dg-warning "uninitialized" "real uninitialized var warning" } */
+
+  return 0;
+}

gcc/testsuite/gcc.dg/uninit-pred-3_a.c

@@ -0,0 +1,28 @@
+/* { dg-do compile } */
+/* { dg-options "-Wuninitialized -O2" } */
+
+int g;
+void bar();
+void blah(int);
+
+int foo (int n, int m, int r)
+{
+  int flag = 0;
+  int v;
+
+  if (n)
+    {
+      v = r;
+      flag = 1;
+    }
+
+  if (m)
+    g++;
+  else 
+    bar();
+
+  if (r > 0)
+    if (flag)
+      blah(v); /* {dg-bogus "uninitialized" "bogus warning" } */
+  return 0;
+}

gcc/testsuite/gcc.dg/uninit-pred-3_b.c

@@ -0,0 +1,33 @@
+/* { dg-do compile } */
+/* { dg-options "-Wuninitialized -O2" } */
+
+int g;
+void bar();
+void blah(int);
+
+int foo (int n, int m, int r)
+{
+  int flag = 0;
+  int v;
+
+  if (n)
+    {
+      v = r;
+      flag = 1;
+    }
+
+  if (m)
+    g++;
+  else 
+    bar();
+
+  if (r > 0)
+     goto use;
+  if (flag)
+    {
+use:
+      blah(v); /* { dg-warning "uninitialized" "real warning" } */
+    }
+
+  return 0;
+}

gcc/testsuite/gcc.dg/uninit-pred-3_c.c

@@ -0,0 +1,28 @@
+/* { dg-do compile } */
+/* { dg-options "-Wuninitialized -O2" } */
+
+int g;
+void bar();
+void blah(int);
+
+int foo (int n, int m, int r)
+{
+  int flag = 0;
+  int v;
+
+  if (n)
+    {
+      v = r;
+      flag = -1;
+    }
+
+  if (m)
+    g++;
+  else 
+    bar();
+
+  if (r > 0)
+    if (flag < 0)
+      blah(v); /* {dg-bogus "uninitialized" "bogus warning" } */
+  return 0;
+}

gcc/testsuite/gcc.dg/uninit-pred-3_d.c

@@ -0,0 +1,28 @@
+/* { dg-do compile } */
+/* { dg-options "-Wuninitialized -O2" } */
+
+int g;
+void bar();
+void blah(int);
+
+int foo (int n, int m, int r)
+{
+  int flag = 0;
+  int v;
+
+  if (n)
+    {
+      v = r;
+      flag = -1;
+    }
+
+  if (m)
+    g++;
+  else 
+    bar();
+
+  if (r > 0)
+    if (flag  == -1)
+      blah(v); /* {dg-bogus "uninitialized" "bogus warning" } */
+  return 0;
+}

gcc/testsuite/gcc.dg/uninit-pred-3_e.c

@@ -0,0 +1,28 @@
+/* { dg-do compile } */
+/* { dg-options "-Wuninitialized -O2" } */
+
+int g;
+void bar();
+void blah(int);
+
+int foo (int n, int m, int r)
+{
+  int flag = 0;
+  int v;
+
+  if (n)
+    {
+      v = r;
+      flag = -1;
+    }
+
+  if (m)
+    g++;
+  else 
+    bar();
+
+  if (r > 0)
+    if (flag  <= 0 )
+      blah(v); /* { dg-warning "uninitialized" "real warning" } */
+  return 0;
+}

gcc/testsuite/gcc.dg/uninit-pred-4_a.c

@@ -0,0 +1,43 @@
+/* { dg-do compile } */
+/* { dg-options "-Wuninitialized -O2" } */
+
+int g;
+void bar();
+void blah(int);
+int foo (int n, int m, int r, int t)
+{
+  int flag = 0;
+  int v;
+
+  if (t)
+    {
+      if (n)
+        {
+          v = r;    /* init path 1 */
+          flag = 1;
+        }
+
+      if (m)
+        g++;
+      else 
+        bar();
+
+      if (flag)  /* properly  guarded */
+        blah(v); /* { dg-bogus "uninitialized" "bogus warning" } */
+    }
+  else
+    {
+      v = r+1; /* init path 2 */
+      flag = 2;
+    }
+
+  if (m)
+    g++;
+  else 
+    bar();
+
+  if (flag)  /* properly guarded */
+    blah(v); /* { dg-bogus "uninitialized" "bogus warning" } */
+
+  return 0;
+}

gcc/testsuite/gcc.dg/uninit-pred-4_b.c

@@ -0,0 +1,40 @@
+/* { dg-do compile } */
+/* { dg-options "-Wuninitialized -O2" } */
+
+int g;
+void bar();
+void blah(int);
+int foo (int n, int m, int r, int t)
+{
+  int flag = 0;
+  int v;
+
+  if (t)
+    {
+      if (n)
+        {
+          v = r;    /* init path 1 */
+          flag = 1;
+        }
+
+      if (m) g++;
+      else bar();
+
+      if (flag)  /* properly  guarded */
+        blah(v); /* { dg-bogus "uninitialized" "bogus warning" } */
+    }
+  else
+    {
+      v = r+1; /* init path 2 */
+      flag = 2;
+    }
+
+  if (m) g++;
+  else bar();
+
+  if (g)   /* guard can not be determined statically to be safe */
+    blah(v); /* { dg-warning "uninitialized" "real warning" } */
+
+  return 0;
+}
+

gcc/testsuite/gcc.dg/uninit-pred-5_a.c

@@ -0,0 +1,41 @@
+/* { dg-do compile } */
+/* { dg-options "-Wuninitialized -O2" } */
+
+int g;
+int bar();
+int blah(int);
+void t(int);
+
+__attribute__((always_inline)) 
+int foo (int n, int* v, int r)
+{
+  int flag = 0;
+  if (r > n)
+    {
+      *v = bar();
+      flag = 1;
+    }
+
+  if (n > g)
+    g++;
+  else 
+    bar();
+
+  return flag;
+}
+
+int a[100];
+int b[100];
+int blah(int n)
+{
+  int i;
+   for (i = 0 ; i < n; i++)
+     {
+       int v;
+       if (!foo (n, &v, b[i]))
+         return 0;
+       t (v); /* { dg-bogus "uninitialized" "bogus warning" } */
+     }
+   return 1;
+}
+	

gcc/testsuite/gcc.dg/uninit-pred-5_b.c

@@ -0,0 +1,41 @@
+/* { dg-do compile } */
+/* { dg-options "-Wuninitialized -O2" } */
+
+int g;
+int bar();
+int blah(int);
+void t(int);
+
+__attribute__((always_inline)) 
+int foo (int n, int* v, int r)
+{
+  int flag = 0;
+  if (r > n)
+    {
+      *v = bar();
+      flag = 1;
+    }
+
+  if (n > g)
+    g++;
+  else 
+    bar();
+
+  return flag;
+}
+
+int a[100];
+int b[100];
+int blah(int n)
+{
+  int i;
+   for (i = 0 ; i < n; i++)
+     {
+       int v;
+       if (foo (n, &v, b[i]))
+         return 0;
+       t (v); /* { dg-warning "uninitialized" "real warning" } */
+     }
+   return 1;
+}
+	

gcc/testsuite/gcc.dg/uninit-pred-6_a.c

@@ -0,0 +1,40 @@
+
+/* { dg-do compile } */
+/* { dg-options "-Wuninitialized -O2" } */
+
+int g;
+void bar();
+void blah(int);
+
+int foo (int n, int l, int m, int r)
+{
+  int v;
+
+  if (n && l)
+    v = r;
+
+  if (m) g++;
+  else   bar();
+
+  if ( n && l)
+      blah(v); /* { dg-bogus "uninitialized" "bogus warning" } */
+
+  return 0;
+}
+
+int foo_2 (int n, int l, int m, int r)
+{
+  int v;
+
+  if (n && l)
+    v = r;
+
+  if (m) g++;
+  else   bar();
+
+  if (n)
+      blah (v); /* { dg-warning "uninitialized" "warning" } */
+
+  return 0;
+}
+

gcc/testsuite/gcc.dg/uninit-pred-6_b.c

@@ -0,0 +1,46 @@
+
+/* { dg-do compile } */
+/* { dg-options "-Wuninitialized -O2" } */
+
+int g;
+void bar();
+void blah(int);
+
+int foo (int n, int l, int m, int r)
+{
+  int v;
+
+  if (n)
+    if (l)
+      v = r;
+
+  if (m) g++;
+  else   bar();
+
+  if ( n && l)
+      blah(v); /* { dg-bogus "uninitialized" "bogus warning" } */
+
+  if (l)
+    if (n)
+      blah(v); /* { dg-bogus "uninitialized" "bogus warning" } */
+
+  return 0;
+}
+
+int foo_2 (int n, int l, int m, int r)
+{
+  int v;
+
+  if (n)
+    if (l)
+      v = r;
+
+  if (m) g++;
+  else   bar();
+
+  if (n || l)
+      blah (v); /* { dg-warning "uninitialized" "warning" } */
+
+  return 0;
+}
+

gcc/testsuite/gcc.dg/uninit-pred-6_c.c

@@ -0,0 +1,46 @@
+
+/* { dg-do compile } */
+/* { dg-options "-Wuninitialized -O2" } */
+
+int g;
+void bar();
+void blah(int);
+
+int foo (int n, int l, int m, int r)
+{
+  int v;
+
+  if (n > 10)
+    if (l)
+      v = r;
+
+  if (m) g++;
+  else   bar();
+
+  if ( (n > 10) && l)
+      blah(v); /* { dg-bogus "uninitialized" "bogus warning" } */
+
+  if (l)
+    if (n > 12)
+      blah(v); /* { dg-bogus "uninitialized" "bogus warning" } */
+
+  return 0;
+}
+
+int foo_2 (int n, int l, int m, int r)
+{
+  int v;
+
+  if (n > 10)
+    if (l)
+      v = r;
+
+  if (m) g++;
+  else   bar();
+
+  if (n > 8 )
+    if (l)
+      blah (v); /* { dg-warning "uninitialized" "warning" } */
+
+  return 0;
+}

gcc/testsuite/gcc.dg/uninit-pred-6_d.c

@@ -0,0 +1,24 @@
+
+/* { dg-do compile } */
+/* { dg-options "-Wuninitialized -O2" } */
+
+int g;
+void bar();
+void blah(int);
+
+int foo (int n, int l, int m, int r)
+{
+  int v;
+
+  if (n)
+    v = r;
+
+  if (m) g++;
+  else   bar();
+
+  if ( n && l)
+      blah(v); /* { dg-bogus "uninitialized" "bogus warning" } */
+
+  return 0;
+}
+

gcc/testsuite/gcc.dg/uninit-pred-6_e.c

@@ -0,0 +1,43 @@
+
+/* { dg-do compile } */
+/* { dg-options "-Wuninitialized -O2" } */
+
+int g;
+void bar();
+void blah(int);
+
+int foo (int n, int l, int m, int r)
+{
+  int v;
+
+  if (n > 10)
+    v = r;
+
+  if (m) g++;
+  else   bar();
+
+  if ( (n > 10) && (l < 100))
+      blah(v); /* { dg-bogus "uninitialized" "bogus warning" } */
+
+  if ( n > 100 )
+      blah(v); /* { dg-bogus "uninitialized" "bogus warning" } */
+
+  return 0;
+}
+
+int foo_2 (int n, int l, int m, int r)
+{
+  int v;
+
+  if (n > 10)
+    v = r;
+
+  if (m) g++;
+  else   bar();
+
+  if ( n < 10)
+      blah (v); /* { dg-warning "uninitialized" "warning" } */
+
+
+  return 0;
+}

gcc/testsuite/gcc.dg/uninit-pred-7_a.c

@@ -0,0 +1,54 @@
+
+/* { dg-do compile } */
+/* { dg-options "-Wuninitialized -O2" } */
+
+int g;
+void bar();
+void blah(int);
+
+int foo (int n, int l, int m, int r)
+{
+  int v;
+
+  if (n || l)
+    v = r;
+
+  if (m) g++;
+  else   bar();
+
+  if ( n && l)
+      blah(v); /* { dg-bogus "uninitialized" "bogus warning" } */
+
+  if ( n )
+      blah(v); /* { dg-bogus "uninitialized" "bogus warning" } */
+
+  if ( l )
+      blah(v); /* { dg-bogus "uninitialized" "bogus warning" } */
+
+  return 0;
+}
+
+int foo_2 (int n, int l, int m, int r)
+{
+  int v;
+
+  if (n || l)
+    v = r;
+
+  if (m) g++;
+  else   bar();
+
+  if ( n && l)
+      blah(v); /* { dg-bogus "uninitialized" "bogus warning" } */
+
+  if ( n )
+      blah(v); /* { dg-bogus "uninitialized" "bogus warning" } */
+
+  if (m || l)
+      blah (v); /* { dg-warning "uninitialized" "warning" } */
+
+  if ( l )
+      blah(v); /* { dg-bogus "uninitialized" "bogus warning" } */
+
+  return 0;
+}

gcc/testsuite/gcc.dg/uninit-pred-7_b.c

@@ -0,0 +1,23 @@
+
+/* { dg-do compile } */
+/* { dg-options "-Wuninitialized -O2" } */
+
+int g;
+void bar();
+void blah(int);
+
+int foo (int n, int l, int m, int r)
+{
+  int v;
+
+  if (n > 10)
+    v = r;
+
+  if (m) g++;
+  else   bar();
+
+  if (( n > 10) || (l != 100))
+      blah (v); /* { dg-warning "uninitialized" "warning" } */
+
+  return 0;
+}

gcc/testsuite/gcc.dg/uninit-pred-7_c.c

@@ -0,0 +1,33 @@
+
+/* { dg-do compile } */
+/* { dg-options "-Wuninitialized -O2" } */
+
+int g;
+void bar();
+void blah(int);
+
+int foo (int n, int l, int m, int r)
+{
+  int v;
+
+  if (n)
+    v = r;
+
+  if (m) g++;
+  else   bar();
+
+  if (n )
+    {
+      if (l)
+        g++;
+      else 
+        goto l;
+    }
+  else
+    {
+l:
+      blah (v); /* { dg-warning "uninitialized" "warning" } */
+    }
+
+  return 0;
+}

gcc/testsuite/gcc.dg/uninit-pred-8_a.c

@@ -0,0 +1,45 @@
+
+/* { dg-do compile } */
+/* { dg-options "-Wuninitialized -O2" } */
+
+int g;
+void bar();
+void blah(int);
+
+int foo (int n, int l, int m, int r)
+{
+  int v;
+
+  if (n || m || r || l)
+    v = r;
+
+  if (m) g++;
+  else   bar();
+
+  if ( n ||  m || r || l)
+      blah(v); /* { dg-bogus "uninitialized" "bogus warning" } */
+
+  if ( n )
+      blah(v); /* { dg-bogus "uninitialized" "bogus warning" } */
+
+  if ( l )
+      blah(v); /* { dg-bogus "uninitialized" "bogus warning" } */
+
+  return 0;
+}
+
+int foo_2 (int n, int l, int m, int r)
+{
+  int v;
+
+  if (n || m || r )
+    v = r;
+
+  if (m) g++;
+  else   bar();
+
+  if ( n || m || r || l)
+      blah(v); /* { dg-warning "uninitialized" "warning" } */
+
+  return 0;
+}

gcc/testsuite/gcc.dg/uninit-pred-8_b.c

@@ -0,0 +1,45 @@
+
+/* { dg-do compile } */
+/* { dg-options "-Wuninitialized -O2" } */
+
+int g;
+void bar();
+void blah(int);
+
+int foo (int n, int l, int m, int r)
+{
+  int v;
+
+  if (n < 10 || m > 100 || r < 20 || l)
+    v = r;
+
+  if (m) g++;
+  else   bar();
+
+  if ( n < 10 ||  m > 100 || r < 20 )
+      blah(v); /* { dg-bogus "uninitialized" "bogus warning" } */
+
+  if ( n < 10 ||  m > 100 || r < 10 )
+      blah(v); /* { dg-bogus "uninitialized" "bogus warning" } */
+
+  return 0;
+}
+
+int foo_2 (int n, int l, int m, int r)
+{
+  int v;
+
+  if (n < 10 || m > 100 || r < 20 || l)
+    v = r;
+
+  if (m) g++;
+  else   bar();
+
+  if ( n < 10 ||  m > 100 || r < 20 )
+      blah(v); /* { dg-bogus "uninitialized" "bogus warning" } */
+
+  if ( n < 10 ||  m > 100 || r < 30 )
+      blah(v); /* { dg-warning "uninitialized" "warning" } */
+
+  return 0;
+}

gcc/testsuite/gcc.dg/uninit-pred-8_c.c

@@ -0,0 +1,39 @@
+
+/* { dg-do compile } */
+/* { dg-options "-Wuninitialized -O2" } */
+
+int g;
+void bar();
+void blah(int);
+
+int foo (int n, int l, int m, int r)
+{
+  int v;
+
+  if (n < 10 && m > 100  && r < 20 )
+    v = r;
+
+  if (m) g++; 
+  else  bar();
+
+  if ( n <= 8 &&  m > 101  && r < 19 )
+      blah(v); /* { dg-bogus "uninitialized" "bogus warning" } */
+
+  return 0;
+}
+
+int foo_2 (int n, int l, int m, int r)
+{
+  int v;
+
+  if (n < 10 && m > 100  && r < 20 )
+    v = r;
+
+  if (m) g++; 
+  else  bar();
+
+  if ( n <= 8 &&  m > 99  && r < 19 )
+      blah(v); /* { dg-warning "uninitialized" "warning" } */
+
+  return 0;
+}

gcc/testsuite/gcc.dg/uninit-pred-9_a.c

@@ -0,0 +1,23 @@
+
+/* { dg-do compile } */
+/* { dg-options "-Wuninitialized -O2" } */
+
+int g;
+void bar();
+void blah(int);
+
+int foo (int n, int l, int m, int r)
+{
+  int v;
+
+  if ( (n < 10) && (m == l)  && (r < 20) )
+    v = r;
+
+  if (m) g++; 
+  else  bar();
+
+  if ( (n <= 8) &&  (m == l)  && (r < 19) )
+      blah(v); /* { dg-bogus "uninitialized" "bogus warning" } */
+
+  return 0;
+}

gcc/testsuite/gcc.dg/uninit-pred-9_b.c

@@ -0,0 +1,44 @@
+
+/* { dg-do compile } */
+/* { dg-options "-Wuninitialized -O2" } */
+
+int g;
+void bar();
+void blah(int);
+
+int foo (int n, int l, int m, int r)
+{
+  int v;
+
+  if ( (n < 10) && (m != 100)  && (r < 20) )
+    v = r;
+
+  if (m) g++; 
+  else  bar();
+
+  if (l > 100)
+    if ( (n <= 9) &&  (m < 100)  && (r < 19) )
+      blah(v); /* { dg-bogus "uninitialized" "bogus warning" } */
+
+  if ( (n <= 8) &&  (m < 99)  && (r < 19) )
+      blah(v); /* { dg-bogus "uninitialized" "bogus warning" } */
+
+  return 0;
+}
+
+int foo_2 (int n, int l, int m, int r)
+{
+  int v;
+
+  if ( (n < 10) && (m != 100)  && (r < 20) )
+    v = r;
+
+  if (m) g++; 
+  else  bar();
+
+  if (l > 100)
+    if ( (n <= 8) &&  (m < 101)  && (r < 19) )
+      blah(v); /* { dg-warning "uninitialized" "real warning" } */
+
+  return 0;
+}

gcc/timevar.def

@@ -219,6 +219,7 @@ DEFTIMEVAR (TV_FINAL                 , "final")
 DEFTIMEVAR (TV_SYMOUT                , "symout")
 DEFTIMEVAR (TV_VAR_TRACKING          , "variable tracking")
 DEFTIMEVAR (TV_TREE_IFCOMBINE        , "tree if-combine")
+DEFTIMEVAR (TV_TREE_UNINIT           , "uninit var anaysis")
 DEFTIMEVAR (TV_PLUGIN_INIT           , "plugin initialization")
 DEFTIMEVAR (TV_PLUGIN_RUN            , "plugin execution")
 

gcc/tree-flow.h

@@ -575,6 +575,8 @@ extern void flush_pending_stmts (edge);
 extern void verify_ssa (bool);
 extern void delete_tree_ssa (void);
 extern bool ssa_undefined_value_p (tree);
+extern void warn_uninit (tree, const char *, void *);
+extern unsigned int warn_uninitialized_vars (bool);
 extern void execute_update_addresses_taken (bool);
 
 /* Call-back function for walk_use_def_chains().  At each reaching

gcc/tree-ssa.c

@@ -1603,25 +1603,6 @@ walk_use_def_chains (tree var, walk_use_def_chains_fn fn, void *data,
 }
 
 
-/* Return true if T, an SSA_NAME, has an undefined value.  */
-
-bool
-ssa_undefined_value_p (tree t)
-{
-  tree var = SSA_NAME_VAR (t);
-
-  /* Parameters get their initial value from the function entry.  */
-  if (TREE_CODE (var) == PARM_DECL)
-    return false;
-
-  /* Hard register variables get their initial value from the ether.  */
-  if (TREE_CODE (var) == VAR_DECL && DECL_HARD_REGISTER (var))
-    return false;
-
-  /* The value is undefined iff its definition statement is empty.  */
-  return gimple_nop_p (SSA_NAME_DEF_STMT (t));
-}
-
 /* Emit warnings for uninitialized variables.  This is done in two passes.
 
    The first pass notices real uses of SSA names with undefined values.
@@ -1640,7 +1621,7 @@ ssa_undefined_value_p (tree t)
 /* Emit a warning for T, an SSA_NAME, being uninitialized.  The exact
    warning text is in MSGID and LOCUS may contain a location or be null.  */
 
-static void
+void
 warn_uninit (tree t, const char *gmsgid, void *data)
 {
   tree var = SSA_NAME_VAR (t);
@@ -1770,28 +1751,7 @@ warn_uninitialized_var (tree *tp, int *walk_subtrees, void *data_)
   return NULL_TREE;
 }
 
-/* Look for inputs to PHI that are SSA_NAMEs that have empty definitions
-   and warn about them.  */
-
-static void
-warn_uninitialized_phi (gimple phi)
-{
-  size_t i, n = gimple_phi_num_args (phi);
-
-  /* Don't look at memory tags.  */
-  if (!is_gimple_reg (gimple_phi_result (phi)))
-    return;
-
-  for (i = 0; i < n; ++i)
-    {
-      tree op = gimple_phi_arg_def (phi, i);
-      if (TREE_CODE (op) == SSA_NAME)
-	warn_uninit (op, "%qD may be used uninitialized in this function",
-		     NULL);
-    }
-}
-
-static unsigned int
+unsigned int
 warn_uninitialized_vars (bool warn_possibly_uninitialized)
 {
   gimple_stmt_iterator gsi;
@@ -1800,7 +1760,6 @@ warn_uninitialized_vars (bool warn_possibly_uninitialized)
 
   data.warn_possibly_uninitialized = warn_possibly_uninitialized;
 
-  calculate_dominance_info (CDI_POST_DOMINATORS);
 
   FOR_EACH_BB (bb)
     {
@@ -1818,10 +1777,6 @@ warn_uninitialized_vars (bool warn_possibly_uninitialized)
 	}
     }
 
-  /* Post-dominator information can not be reliably updated. Free it
-     after the use.  */
-
-  free_dominance_info (CDI_POST_DOMINATORS);
   return 0;
 }
 
@@ -1834,25 +1789,14 @@ execute_early_warn_uninitialized (void)
      as possible, thus don't do it here.  However, without
      optimization we need to warn here about "may be uninitialized".
   */
+  calculate_dominance_info (CDI_POST_DOMINATORS);
+
   warn_uninitialized_vars (/*warn_possibly_uninitialized=*/!optimize);
-  return 0;
-}
 
-static unsigned int
-execute_late_warn_uninitialized (void)
-{
-  basic_block bb;
-  gimple_stmt_iterator gsi;
-
-  /* Re-do the plain uninitialized variable check, as optimization may have
-     straightened control flow.  Do this first so that we don't accidentally
-     get a "may be" warning when we'd have seen an "is" warning later.  */
-  warn_uninitialized_vars (/*warn_possibly_uninitialized=*/1);
-
-  FOR_EACH_BB (bb)
-    for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
-      warn_uninitialized_phi (gsi_stmt (gsi));
+  /* Post-dominator information can not be reliably updated. Free it
+     after the use.  */
 
+  free_dominance_info (CDI_POST_DOMINATORS);
   return 0;
 }
 
@@ -1881,25 +1825,6 @@ struct gimple_opt_pass pass_early_warn_uninitialized =
  }
 };
 
-struct gimple_opt_pass pass_late_warn_uninitialized =
-{
- {
-  GIMPLE_PASS,
-  "*late_warn_uninitialized",		/* name */
-  gate_warn_uninitialized,		/* gate */
-  execute_late_warn_uninitialized,	/* execute */
-  NULL,					/* sub */
-  NULL,					/* next */
-  0,					/* static_pass_number */
-  TV_NONE,				/* tv_id */
-  PROP_ssa,				/* properties_required */
-  0,					/* properties_provided */
-  0,					/* properties_destroyed */
-  0,					/* todo_flags_start */
-  0                                     /* todo_flags_finish */
- }
-};
-
 /* Compute TREE_ADDRESSABLE and DECL_GIMPLE_REG_P for local variables.  */
 
 void