re PR target/50962 (Additional opportunity for AGU stall avoidance optimization for Atom processor)

gcc/
	PR target/50962
	* config/i386/i386-protos.h (ix86_use_lea_for_mov): New.
	* config/i386/i386.c (ix86_use_lea_for_mov): Likewise.
	* config/i386/i386.md (movsi_internal): Emit lea if profitable.
	(movdi_internal_rex64): Likewise.

From-SVN: r181077

gcc/config/i386/i386-protos.h

@@ -93,6 +93,7 @@ extern bool ix86_binary_operator_ok (enum rtx_code, enum machine_mode, rtx[]);
 extern bool ix86_lea_outperforms (rtx, unsigned int, unsigned int,
 				  unsigned int, unsigned int);
 extern bool ix86_avoid_lea_for_add (rtx, rtx[]);
+extern bool ix86_use_lea_for_mov (rtx, rtx[]);
 extern bool ix86_avoid_lea_for_addr (rtx, rtx[]);
 extern void ix86_split_lea_for_addr (rtx[], enum machine_mode);
 extern bool ix86_lea_for_add_ok (rtx, rtx[]);

gcc/config/i386/i386.c

@@ -16509,6 +16509,29 @@ ix86_avoid_lea_for_add (rtx insn, rtx operands[])
     return !ix86_lea_outperforms (insn, regno0, regno1, regno2, 1);
 }
 
+/* Return true if we should emit lea instruction instead of mov
+   instruction.  */
+
+bool
+ix86_use_lea_for_mov (rtx insn, rtx operands[])
+{
+  unsigned int regno0;
+  unsigned int regno1;
+
+  /* Check if we need to optimize.  */
+  if (!TARGET_OPT_AGU || optimize_function_for_size_p (cfun))
+    return false;
+
+  /* Use lea for reg to reg moves only.  */
+  if (!REG_P (operands[0]) || !REG_P (operands[1]))
+    return false;
+
+  regno0 = true_regnum (operands[0]);
+  regno1 = true_regnum (operands[1]);
+
+  return ix86_lea_outperforms (insn, regno0, regno1, -1, 0);
+}
+
 /* Return true if we need to split lea into a sequence of
    instructions to avoid AGU stalls. */
 

gcc/config/i386/i386.md

@@ -2053,6 +2053,8 @@
 	return "mov{l}\t{%k1, %k0|%k0, %k1}";
       else if (which_alternative == 2)
 	return "movabs{q}\t{%1, %0|%0, %1}";
+      else if (ix86_use_lea_for_mov(insn, operands))
+	return "lea{q}\t{%a1, %0|%0, %a1}";
       else
 	return "mov{q}\t{%1, %0|%0, %1}";
     }
@@ -2288,7 +2290,10 @@
 
     default:
       gcc_assert (!flag_pic || LEGITIMATE_PIC_OPERAND_P (operands[1]));
-      return "mov{l}\t{%1, %0|%0, %1}";
+      if (ix86_use_lea_for_mov(insn, operands))
+	return "lea{l}\t{%a1, %0|%0, %a1}";
+      else
+	return "mov{l}\t{%1, %0|%0, %1}";
     }
 }
   [(set (attr "type")

gcc/testsuite/ChangeLog

+2011-11-07  Enkovich Ilya  <ilya.enkovich@intel.com>
+
+	PR target/50962
+	* config/i386/i386-protos.h (ix86_use_lea_for_mov): New.
+	* config/i386/i386.c (ix86_use_lea_for_mov): Likewise.
+	* config/i386/i386.md (movsi_internal): Emit lea if profitable.
+	(movdi_internal_rex64): Likewise.
 
 2011-11-07  Sergey Ostanevich  <sergos.gnu@gmail.com>