re PR rtl-optimization/58831 (wrong code at -O2 and -O3 on x86_64-linux-gnu in 64-bit mode)

PR rtl-optimization/58831
	* alias.c (init_alias_analysis): At the beginning of each iteration, set
	the reg_seen[N] flag if static_reg_base_value[N] is non-null.

From-SVN: r204058

gcc/ChangeLog

@@ -1,3 +1,9 @@
+2013-10-25  Eric Botcazou  <ebotcazou@adacore.com>
+
+	PR rtl-optimization/58831
+	* alias.c (init_alias_analysis): At the beginning of each iteration, set
+	the reg_seen[N] flag if static_reg_base_value[N] is non-null.
+
 2013-10-25  Eric Botcazou  <ebotcazou@adacore.com>
 
 	* recog.c (search_ofs): New static variable moved from...

gcc/alias.c

@@ -2810,16 +2810,13 @@ init_alias_analysis (void)
       /* Wipe the reg_seen array clean.  */
       memset (reg_seen, 0, maxreg);
 
-      /* Mark all hard registers which may contain an address.
-	 The stack, frame and argument pointers may contain an address.
-	 An argument register which can hold a Pmode value may contain
-	 an address even if it is not in BASE_REGS.
-
-	 The address expression is VOIDmode for an argument and
-	 Pmode for other registers.  */
-
-      memcpy (new_reg_base_value, static_reg_base_value,
-	      FIRST_PSEUDO_REGISTER * sizeof (rtx));
+      /* Initialize the alias information for this pass.  */
+      for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
+	if (static_reg_base_value[i])
+	  {
+	    new_reg_base_value[i] = static_reg_base_value[i];
+	    reg_seen[i] = 1;
+	  }
 
       /* Walk the insns adding values to the new_reg_base_value array.  */
       for (insn = get_insns (); insn; insn = NEXT_INSN (insn))

gcc/testsuite/ChangeLog

@@ -1,3 +1,7 @@
+2013-10-25  Eric Botcazou  <ebotcazou@adacore.com>
+
+	* gcc.c-torture/execute/pr58831.c: New test.
+
 2013-10-16  Paolo Carlini  <paolo.carlini@oracle.com>
 
 	PR c++/58633

gcc/testsuite/gcc.c-torture/execute/pr58831.c

@@ -0,0 +1,40 @@
+#include <assert.h>
+
+int a, *b, c, d, f, **i, p, q, *r;
+short o, j;
+
+static int __attribute__((noinline, noclone))
+fn1 (int *p1, int **p2)
+{
+  int **e = &b;
+  for (; p; p++)
+    *p1 = 1;
+  *e = *p2 = &d;
+
+  assert (r);
+
+  return c;
+}
+
+static int ** __attribute__((noinline, noclone))
+fn2 (void)
+{
+  for (f = 0; f != 42; f++)
+    {
+      int *g[3] = {0, 0, 0};
+      for (o = 0; o; o--)
+        for (; a > 1;)
+          {
+            int **h[1] = { &g[2] };
+          }
+    }
+  return &r;
+}
+
+int
+main (void)
+{
+  i = fn2 ();
+  fn1 (b, i);
+  return 0;
+}