Optimise comparison where intermediate result not used (AArch64)

From-SVN: r193450

gcc/ChangeLog

+2012-11-12  Ian Bolton  <ian.bolton@arm.com>
+
+	* config/aarch64/aarch64.md (*compare_neg<mode>): New pattern.
+
 2012-11-12  Tobias Burnus  <burnus@net-b.de>
 
 	* doc/invoke.texi: Move -faddress-sanitizer from Optimization

gcc/config/aarch64/aarch64.md

@@ -1318,6 +1318,17 @@
    (set_attr "mode" "<MODE>")]
 )
 
+(define_insn "*compare_neg<mode>"
+  [(set (reg:CC CC_REGNUM)
+	(compare:CC
+	 (match_operand:GPI 0 "register_operand" "r")
+	 (neg:GPI (match_operand:GPI 1 "register_operand" "r"))))]
+  ""
+  "cmn\\t%<w>0, %<w>1"
+  [(set_attr "v8type" "alus")
+   (set_attr "mode" "<MODE>")]
+)
+
 (define_insn "*add_<shift>_<mode>"
   [(set (match_operand:GPI 0 "register_operand" "=rk")
 	(plus:GPI (ASHIFT:GPI (match_operand:GPI 1 "register_operand" "r")

gcc/testsuite/ChangeLog

+2012-11-12  Ian Bolton  <ian.bolton@arm.com>
+
+	* gcc.target/aarch64/cmn.c: New test.
+	* gcc.target/aarch64/adds.c: New test.
+	* gcc.target/aarch64/subs.c: New test.
+
 2012-11-12  Tobias Burnus  <burnus@net-b.de>
 
 	PR fortran/55272

gcc/testsuite/gcc.target/aarch64/adds.c

+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+
+int z;
+int
+foo (int x, int y)
+{
+  int l = x + y;
+  if (l == 0)
+    return 5;
+
+  /* { dg-final { scan-assembler "adds\tw\[0-9\]" } } */
+  z = l ;
+  return 25;
+}
+
+typedef long long s64;
+
+s64 zz;
+s64
+foo2 (s64 x, s64 y)
+{
+  s64 l = x + y;
+  if (l < 0)
+    return 5;
+
+  /* { dg-final { scan-assembler "adds\tx\[0-9\]" } } */
+  zz = l ;
+  return 25;
+}

gcc/testsuite/gcc.target/aarch64/cmn.c

+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+
+int
+foo (int a, int b)
+{
+  if (a + b)
+    return 5;
+  else
+    return 2;
+  /* { dg-final { scan-assembler "cmn\tw\[0-9\]" } } */
+}
+
+typedef long long s64;
+
+s64
+foo2 (s64 a, s64 b)
+{
+  if (a + b)
+    return 5;
+  else
+    return 2;
+  /* { dg-final { scan-assembler "cmn\tx\[0-9\]" } } */
+}  

gcc/testsuite/gcc.target/aarch64/subs.c

+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+
+int z;
+int
+foo (int x, int y)
+{
+  int l = x - y;
+  if (l == 0)
+    return 5;
+
+  /* { dg-final { scan-assembler "subs\tw\[0-9\]" } } */
+  z = l ;
+  return 25;
+}
+
+typedef long long s64;
+
+s64 zz;
+s64
+foo2 (s64 x, s64 y)
+{
+  s64 l = x - y;
+  if (l < 0)
+    return 5;
+
+  /* { dg-final { scan-assembler "subs\tx\[0-9\]" } } */
+  zz = l ;
+  return 25;
+}