# DP: Fix PR target/59744 (AArch64), taken from the trunk.

gcc/
2014-01-10  Richard Earnshaw  <rearnsha@arm.com>

	PR target/59744
	* aarch64-modes.def (CC_Zmode): New flags mode.
	* aarch64.c (aarch64_select_cc_mode): Only allow NEG when the condition
	represents an equality.
	(aarch64_get_condition_code): Handle CC_Zmode.
	* aarch64.md (compare_neg<mode>): Restrict to equality operations.

gcc/testsuite/

2014-01-10  Richard Earnshaw  <rearnsha@arm.com>

	PR target/59744
	* gcc.target/aarch64/cmn-neg.c: Use equality comparisons.
	* gcc.target/aarch64/cmn-neg2.c: New test.

--- a/src/gcc/testsuite/gcc.target/aarch64/cmn-neg.c	(revision 206528)
+++ b/src/gcc/testsuite/gcc.target/aarch64/cmn-neg.c	(revision 206530)
@@ -6,7 +6,7 @@
 void __attribute__ ((noinline))
 foo_s32 (int a, int b)
 {
-  if (a < -b)
+  if (a == -b)
     abort ();
 }
 /* { dg-final { scan-assembler "cmn\tw\[0-9\]" } } */
@@ -14,7 +14,7 @@
 void __attribute__ ((noinline))
 foo_s64 (long long a, long long b)
 {
-  if (a < -b)
+  if (a == -b)
     abort ();
 }
 /* { dg-final { scan-assembler "cmn\tx\[0-9\]" } } */
--- a/src/gcc/testsuite/gcc.target/aarch64/cmn-neg2.c	(revision 0)
+++ b/src/gcc/testsuite/gcc.target/aarch64/cmn-neg2.c	(revision 206530)
@@ -0,0 +1,34 @@
+/* { dg-do run } */
+/* { dg-options "-O2 --save-temps" } */
+
+extern void abort (void);
+
+/* It's unsafe to use CMN in these comparisons.  */
+
+void __attribute__ ((noinline))
+foo_s32 (int a, int b)
+{
+  if (a < -b)
+    abort ();
+}
+
+void __attribute__ ((noinline))
+foo_s64 (unsigned long long a, unsigned long long b)
+{
+  if (a > -b)
+    abort ();
+}
+
+
+int
+main (void)
+{
+  int a = 30;
+  int b = 42;
+  foo_s32 (a, b);
+  foo_s64 (a, b);
+  return 0;
+}
+/* { dg-final { scan-assembler-not "cmn\t" } } */
+
+/* { dg-final { cleanup-saved-temps } } */
--- a/src/gcc/config/aarch64/aarch64.md	(revision 206528)
+++ b/src/gcc/config/aarch64/aarch64.md	(revision 206530)
@@ -1250,8 +1250,8 @@
 )
 
 (define_insn "*compare_neg<mode>"
-  [(set (reg:CC_SWP CC_REGNUM)
-	(compare:CC_SWP
+  [(set (reg:CC_Z CC_REGNUM)
+	(compare:CC_Z
 	 (neg:GPI (match_operand:GPI 0 "register_operand" "r"))
 	 (match_operand:GPI 1 "register_operand" "r")))]
   ""
--- a/src/gcc/config/aarch64/aarch64-modes.def	(revision 206528)
+++ b/src/gcc/config/aarch64/aarch64-modes.def	(revision 206530)
@@ -24,6 +24,7 @@
 CC_MODE (CC_ZESWP); /* zero-extend LHS (but swap to make it RHS).  */
 CC_MODE (CC_SESWP); /* sign-extend LHS (but swap to make it RHS).  */
 CC_MODE (CC_NZ);    /* Only N and Z bits of condition flags are valid.  */
+CC_MODE (CC_Z);     /* Only Z bit of condition flags is valid.  */
 
 /* Vector modes.  */
 VECTOR_MODES (INT, 8);        /*       V8QI V4HI V2SI.  */
--- a/src/gcc/config/aarch64/aarch64.c	(revision 206528)
+++ b/src/gcc/config/aarch64/aarch64.c	(revision 206530)
@@ -3326,17 +3326,24 @@
 	  || GET_CODE (x) == NEG))
     return CC_NZmode;
 
-  /* A compare with a shifted or negated operand.  Because of canonicalization,
+  /* A compare with a shifted operand.  Because of canonicalization,
      the comparison will have to be swapped when we emit the assembly
      code.  */
   if ((GET_MODE (x) == SImode || GET_MODE (x) == DImode)
       && (GET_CODE (y) == REG || GET_CODE (y) == SUBREG)
       && (GET_CODE (x) == ASHIFT || GET_CODE (x) == ASHIFTRT
 	  || GET_CODE (x) == LSHIFTRT
-	  || GET_CODE (x) == ZERO_EXTEND || GET_CODE (x) == SIGN_EXTEND
-	  || GET_CODE (x) == NEG))
+	  || GET_CODE (x) == ZERO_EXTEND || GET_CODE (x) == SIGN_EXTEND))
     return CC_SWPmode;
 
+  /* Similarly for a negated operand, but we can only do this for
+     equalities.  */
+  if ((GET_MODE (x) == SImode || GET_MODE (x) == DImode)
+      && (GET_CODE (y) == REG || GET_CODE (y) == SUBREG)
+      && (code == EQ || code == NE)
+      && GET_CODE (x) == NEG)
+    return CC_Zmode;
+
   /* A compare of a mode narrower than SI mode against zero can be done
      by extending the value in the comparison.  */
   if ((GET_MODE (x) == QImode || GET_MODE (x) == HImode)
@@ -3427,6 +3434,15 @@
 	}
       break;
 
+    case CC_Zmode:
+      switch (comp_code)
+	{
+	case NE: return AARCH64_NE;
+	case EQ: return AARCH64_EQ;
+	default: gcc_unreachable ();
+	}
+      break;
+
     default:
       gcc_unreachable ();
       break;