re PR debug/49676 (inefficiency: DW_AT_GNU_call_site_value calculates everything...

	PR debug/49676
	* dwarf2out.c (size_of_int_loc_descriptor): New function.
	(address_of_int_loc_descriptor): Use it.
	(scompare_loc_descriptor): Optimize EQ/NE comparison with
	constant.

From-SVN: r176083

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index cbc027f..addfcd7 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,11 @@
+2011-07-09  Jakub Jelinek  <jakub@redhat.com>
+
+       PR debug/49676
+       * dwarf2out.c (size_of_int_loc_descriptor): New function.
+       (address_of_int_loc_descriptor): Use it.
+       (scompare_loc_descriptor): Optimize EQ/NE comparison with
+       constant.
+
 2011-07-09  Richard Henderson  <rth@redhat.com>
 
        * config/pdp11/pdp11.md (define_c_enum "unspecv"): New.

diff --git a/gcc/dwarf2out.c b/gcc/dwarf2out.c
index 44035d3..bad0b2d 100644 (file)
--- a/gcc/dwarf2out.c
+++ b/gcc/dwarf2out.c
@@ -10848,44 +10848,53 @@ int_loc_descriptor (HOST_WIDE_INT i)
   return new_loc_descr (op, i, 0);
 }
 
-/* Return loc description representing "address" of integer value.
-   This can appear only as toplevel expression.  */
+/* Return size_of_locs (int_loc_descriptor (i)) without
+   actually allocating it.  */
 
-static dw_loc_descr_ref
-address_of_int_loc_descriptor (int size, HOST_WIDE_INT i)
+static unsigned long
+size_of_int_loc_descriptor (HOST_WIDE_INT i)
 {
-  int litsize;
-  dw_loc_descr_ref loc_result = NULL;
-
-  if (!(dwarf_version >= 4 || !dwarf_strict))
-    return NULL;
-
   if (i >= 0)
     {
       if (i <= 31)
-       litsize = 1;
+       return 1;
       else if (i <= 0xff)
-       litsize = 2;
+       return 2;
       else if (i <= 0xffff)
-       litsize = 3;
+       return 3;
       else if (HOST_BITS_PER_WIDE_INT == 32
               || i <= 0xffffffff)
-       litsize = 5;
+       return 5;
       else
-       litsize = 1 + size_of_uleb128 ((unsigned HOST_WIDE_INT) i);
+       return 1 + size_of_uleb128 ((unsigned HOST_WIDE_INT) i);
     }
   else
     {
       if (i >= -0x80)
-       litsize = 2;
+       return 2;
       else if (i >= -0x8000)
-       litsize = 3;
+       return 3;
       else if (HOST_BITS_PER_WIDE_INT == 32
               || i >= -0x80000000)
-       litsize = 5;
+       return 5;
       else
-       litsize = 1 + size_of_sleb128 (i);
+       return 1 + size_of_sleb128 (i);
     }
+}
+
+/* Return loc description representing "address" of integer value.
+   This can appear only as toplevel expression.  */
+
+static dw_loc_descr_ref
+address_of_int_loc_descriptor (int size, HOST_WIDE_INT i)
+{
+  int litsize;
+  dw_loc_descr_ref loc_result = NULL;
+
+  if (!(dwarf_version >= 4 || !dwarf_strict))
+    return NULL;
+
+  litsize = size_of_int_loc_descriptor (i);
   /* Determine if DW_OP_stack_value or DW_OP_implicit_value
      is more compact.  For DW_OP_stack_value we need:
      litsize + 1 (DW_OP_stack_value)
@@ -11284,6 +11293,28 @@ scompare_loc_descriptor (enum dwarf_location_atom op, rtx rtl,
                  && (unsigned HOST_WIDE_INT) INTVAL (XEXP (rtl, 1))
                     == (INTVAL (XEXP (rtl, 1)) & GET_MODE_MASK (op_mode)))))
        return compare_loc_descriptor (op, op0, op1);
+
+      /* EQ/NE comparison against constant in narrower type than
+        DWARF2_ADDR_SIZE can be performed either as
+        DW_OP_const1u <shift> DW_OP_shl DW_OP_const* <cst << shift>
+        DW_OP_{eq,ne}
+        or
+        DW_OP_const*u <mode_mask> DW_OP_and DW_OP_const* <cst & mode_mask>
+        DW_OP_{eq,ne}.  Pick whatever is shorter.  */
+      if (CONST_INT_P (XEXP (rtl, 1))
+         && GET_MODE_BITSIZE (op_mode) < HOST_BITS_PER_WIDE_INT
+         && (size_of_int_loc_descriptor (shift) + 1
+             + size_of_int_loc_descriptor (INTVAL (XEXP (rtl, 1)) << shift)
+             >= size_of_int_loc_descriptor (GET_MODE_MASK (op_mode)) + 1
+                + size_of_int_loc_descriptor (INTVAL (XEXP (rtl, 1))
+                                              & GET_MODE_MASK (op_mode))))
+       {
+         add_loc_descr (&op0, int_loc_descriptor (GET_MODE_MASK (op_mode)));
+         add_loc_descr (&op0, new_loc_descr (DW_OP_and, 0, 0));
+         op1 = int_loc_descriptor (INTVAL (XEXP (rtl, 1))
+                                   & GET_MODE_MASK (op_mode));
+         return compare_loc_descriptor (op, op0, op1);
+       }
     }
   add_loc_descr (&op0, int_loc_descriptor (shift));
   add_loc_descr (&op0, new_loc_descr (DW_OP_shl, 0, 0));