tree-ssa-forwprop.c (associate_plusminus): Extend (T)(P + A) - (T)P -> (T)A transformation to integer types.

	* tree-ssa-forwprop.c (associate_plusminus): Extend (T)(P + A) - (T)P
	-> (T)A transformation to integer types.

From-SVN: r210807

5 files changed, 95 insertions, 28 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index d2dbcbd..307df9a 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2014-05-22  Eric Botcazou  <ebotcazou@adacore.com>
+
+	* tree-ssa-forwprop.c (associate_plusminus): Extend (T)(P + A) - (T)P
+	-> (T)A transformation to integer types.
+
 2014-05-22  Teresa Johnson  <tejohnson@google.com>
 
 	* gcov-io.c (gcov_position): Use gcov_nonruntime_assert.
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 1b9c60a..4d81463 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,7 @@
+2014-05-22  Eric Botcazou  <ebotcazou@adacore.com>
+
+	* gnat.dg/opt37.ad[sb]: New test.
+
 2014-05-21  Jonathan Wakely  <jwakely@redhat.com>
 
 	PR c/61271
diff --git a/gcc/testsuite/gnat.dg/opt37.adb b/gcc/testsuite/gnat.dg/opt37.adb
new file mode 100644
index 0000000..fe37f90
--- /dev/null
+++ b/gcc/testsuite/gnat.dg/opt37.adb
@@ -0,0 +1,42 @@
+-- { dg-compile }
+-- { dg-options "-O2 -gnato -fdump-tree-optimized" }
+
+package body Opt37 is
+
+   function To_Unchecked (Bits : T_Bit_Array) return Unsigned32 is
+      Value : Unsigned32 := 0;
+   begin
+      for I in Bits'Range loop
+         Value := Value * 2 + Unsigned32 (Bits(I));
+      end loop;
+      return Value;
+   end;
+
+   function To_Scalar (Bits : T_Bit_Array) return Positive is
+      Tmp   : Unsigned32;
+      Value : Positive;
+   begin
+      Tmp := To_Unchecked (Bits);
+      if Tmp in 0 .. Unsigned32 (Positive'last) then
+         Value := Positive (Tmp);
+      else
+         Value := -Positive (Unsigned32'last - Tmp);
+         if Value > Positive'first then
+            Value := Value - 1;
+         else
+            raise Program_Error;
+         end if;
+      end if;
+      return Value;
+   end;
+
+   function Func (Bit_Array : T_Bit_Array;
+                  Bit_Index : T_Bit_Index) return Positive is
+   begin
+      return To_Scalar (Bit_Array (Bit_Index .. Bit_Index + 1));
+   end;
+
+end Opt37;
+
+-- { dg-final { scan-tree-dump-not "alloca" "optimized" } }
+-- { dg-final { cleanup-tree-dump "optimized" } }
diff --git a/gcc/testsuite/gnat.dg/opt37.ads b/gcc/testsuite/gnat.dg/opt37.ads
new file mode 100644
index 0000000..7507679
--- /dev/null
+++ b/gcc/testsuite/gnat.dg/opt37.ads
@@ -0,0 +1,18 @@
+package Opt37 is

+

+   type T_Bit is range 0 .. 1;

+   for T_Bit'Size use 1;

+

+   type Positive is range 0 .. (2 ** 31) - 1;

+   type Unsigned32 is mod 2 ** 32;

+

+   subtype T_Bit_Count is Positive;

+   subtype T_Bit_Index is T_Bit_Count range 1 .. T_Bit_Count'Last;

+

+   type T_Bit_Array is array (T_Bit_Count range <>) of T_Bit;

+   pragma Pack (T_Bit_Array);

+

+   function Func (Bit_Array : in T_Bit_Array;

+                  Bit_Index : in T_Bit_Index) return Positive;

+

+end Opt37;

diff --git a/gcc/tree-ssa-forwprop.c b/gcc/tree-ssa-forwprop.c
index 563abe0..e863567 100644
--- a/gcc/tree-ssa-forwprop.c
+++ b/gcc/tree-ssa-forwprop.c
@@ -2642,49 +2642,47 @@ associate_plusminus (gimple_stmt_iterator *gsi)
 		  gimple_set_modified (stmt, true);
 		}
 	    }
-	  else if (CONVERT_EXPR_CODE_P (def_code) && code == MINUS_EXPR
+	  else if (code == MINUS_EXPR
+		   && CONVERT_EXPR_CODE_P (def_code)
+		   && TREE_CODE (gimple_assign_rhs1 (def_stmt)) == SSA_NAME
 		   && TREE_CODE (rhs2) == SSA_NAME)
 	    {
-	      /* (T)(ptr + adj) - (T)ptr -> (T)adj.  */
+	      /* (T)(P + A) - (T)P -> (T)A.  */
 	      gimple def_stmt2 = SSA_NAME_DEF_STMT (rhs2);
-	      if (TREE_CODE (gimple_assign_rhs1 (def_stmt)) == SSA_NAME
-		  && is_gimple_assign (def_stmt2)
+	      if (is_gimple_assign (def_stmt2)
 		  && can_propagate_from (def_stmt2)
 		  && CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt2))
 		  && TREE_CODE (gimple_assign_rhs1 (def_stmt2)) == SSA_NAME)
 		{
-		  /* Now we have (T)A - (T)ptr.  */
-		  tree ptr = gimple_assign_rhs1 (def_stmt2);
+		  /* Now we have (T)X - (T)P.  */
+		  tree p = gimple_assign_rhs1 (def_stmt2);
 		  def_stmt2 = SSA_NAME_DEF_STMT (gimple_assign_rhs1 (def_stmt));
 		  if (is_gimple_assign (def_stmt2)
-		      && gimple_assign_rhs_code (def_stmt2) == POINTER_PLUS_EXPR
-		      && gimple_assign_rhs1 (def_stmt2) == ptr)
+		      && can_propagate_from (def_stmt2)
+		      && (gimple_assign_rhs_code (def_stmt2) == POINTER_PLUS_EXPR
+			  || gimple_assign_rhs_code (def_stmt2) == PLUS_EXPR)
+		      && gimple_assign_rhs1 (def_stmt2) == p)
 		    {
-		      /* And finally (T)(ptr + X) - (T)ptr.  */
-		      tree adj = gimple_assign_rhs2 (def_stmt2);
-		      /* If the conversion of the pointer adjustment to the
-		         final type requires a sign- or zero-extension we
-			 have to punt - it is not defined which one is
-			 correct.  */
-		      if (TYPE_PRECISION (TREE_TYPE (rhs1))
-			  <= TYPE_PRECISION (TREE_TYPE (adj))
-			  || (TREE_CODE (adj) == INTEGER_CST
-			      && tree_int_cst_sign_bit (adj) == 0))
+		      /* And finally (T)(P + A) - (T)P.  */
+		      tree a = gimple_assign_rhs2 (def_stmt2);
+		      /* For pointer types, if the conversion of A to the final
+			 type requires a sign- or zero-extension, then we have
+			 to punt - it is not defined which one is correct.  */
+		      if (!POINTER_TYPE_P (TREE_TYPE (rhs1))
+			  || TYPE_PRECISION (TREE_TYPE (rhs1))
+			     <= TYPE_PRECISION (TREE_TYPE (a))
+			  || (TREE_CODE (a) == INTEGER_CST
+			      && tree_int_cst_sign_bit (a) == 0))
 			{
 			  if (useless_type_conversion_p (TREE_TYPE (rhs1),
-							 TREE_TYPE (adj)))
-			    {
-			      code = TREE_CODE (adj);
-			      rhs1 = adj;
-			    }
+							 TREE_TYPE (a)))
+			    code = TREE_CODE (a);
 			  else
-			    {
-			      code = NOP_EXPR;
-			      rhs1 = adj;
-			    }
+			    code = NOP_EXPR;
+			  rhs1 = a;
 			  rhs2 = NULL_TREE;
 			  gimple_assign_set_rhs_with_ops (gsi, code, rhs1,
-							  NULL_TREE);
+							  rhs2);
 			  gcc_assert (gsi_stmt (*gsi) == stmt);
 			  gimple_set_modified (stmt, true);
 			}