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] bit if static_reg_base_value[N] is non-null.

From-SVN: r204055

1 files changed, 7 insertions, 10 deletions

diff --git a/gcc/alias.c b/gcc/alias.c
index 0f9ae73e3d2..1736169b476 100644
--- a/gcc/alias.c
+++ b/gcc/alias.c
@@ -2975,16 +2975,13 @@ init_alias_analysis (void)
       /* Wipe the reg_seen array clean.  */
       bitmap_clear (reg_seen);
 
-      /* 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];
+	    bitmap_set_bit (reg_seen, i);
+	  }
 
       /* Walk the insns adding values to the new_reg_base_value array.  */
       for (i = 0; i < rpo_cnt; i++)