From: Jakub Jelinek <jakub@redhat.com>
Date: Sat, 9 Jul 2011 15:48:42 +0000 (+0200)
Subject: re PR debug/49676 (inefficiency: DW_AT_GNU_call_site_value calculates everything... 
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=5b696ba2dc1b84bf91782c4c89c19eef224d58cf;p=gcc.git

re PR debug/49676 (inefficiency: DW_AT_GNU_call_site_value calculates everything << 32)

	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 cbc027fb933..addfcd73775 100644
--- 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 44035d31de6..bad0b2d53a1 100644
--- 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));