tcg: Introduce TCG_COND_TST{EQ,NE}

Add the enumerators, adjust the helpers to match, and dump.
Not supported anywhere else just yet.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

docs/devel/tcg-ops.rst

@@ -253,6 +253,8 @@ Jumps/Labels
        |   ``TCG_COND_GEU /* unsigned */``
        |   ``TCG_COND_LEU /* unsigned */``
        |   ``TCG_COND_GTU /* unsigned */``
+       |   ``TCG_COND_TSTEQ /* t1 & t2 == 0 */``
+       |   ``TCG_COND_TSTNE /* t1 & t2 != 0 */``
 
 Arithmetic
 ----------

include/tcg/tcg-cond.h

@@ -29,26 +29,34 @@
  * Conditions.  Note that these are laid out for easy manipulation by
  * the functions below:
  *    bit 0 is used for inverting;
- *    bit 1 is signed,
- *    bit 2 is unsigned,
- *    bit 3 is used with bit 0 for swapping signed/unsigned.
+ *    bit 1 is used for conditions that need swapping (signed/unsigned).
+ *    bit 2 is used with bit 1 for swapping.
+ *    bit 3 is used for unsigned conditions.
  */
 typedef enum {
     /* non-signed */
     TCG_COND_NEVER  = 0 | 0 | 0 | 0,
     TCG_COND_ALWAYS = 0 | 0 | 0 | 1,
+
+    /* equality */
     TCG_COND_EQ     = 8 | 0 | 0 | 0,
     TCG_COND_NE     = 8 | 0 | 0 | 1,
+
+    /* "test" i.e. and then compare vs 0 */
+    TCG_COND_TSTEQ  = 8 | 4 | 0 | 0,
+    TCG_COND_TSTNE  = 8 | 4 | 0 | 1,
+
     /* signed */
     TCG_COND_LT     = 0 | 0 | 2 | 0,
     TCG_COND_GE     = 0 | 0 | 2 | 1,
-    TCG_COND_LE     = 8 | 0 | 2 | 0,
-    TCG_COND_GT     = 8 | 0 | 2 | 1,
+    TCG_COND_GT     = 0 | 4 | 2 | 0,
+    TCG_COND_LE     = 0 | 4 | 2 | 1,
+
     /* unsigned */
-    TCG_COND_LTU    = 0 | 4 | 0 | 0,
-    TCG_COND_GEU    = 0 | 4 | 0 | 1,
-    TCG_COND_LEU    = 8 | 4 | 0 | 0,
-    TCG_COND_GTU    = 8 | 4 | 0 | 1,
+    TCG_COND_LTU    = 8 | 0 | 2 | 0,
+    TCG_COND_GEU    = 8 | 0 | 2 | 1,
+    TCG_COND_GTU    = 8 | 4 | 2 | 0,
+    TCG_COND_LEU    = 8 | 4 | 2 | 1,
 } TCGCond;
 
 /* Invert the sense of the comparison.  */
@@ -60,25 +68,49 @@ static inline TCGCond tcg_invert_cond(TCGCond c)
 /* Swap the operands in a comparison.  */
 static inline TCGCond tcg_swap_cond(TCGCond c)
 {
-    return c & 6 ? (TCGCond)(c ^ 9) : c;
+    return (TCGCond)(c ^ ((c & 2) << 1));
+}
+
+/* Must a comparison be considered signed?  */
+static inline bool is_signed_cond(TCGCond c)
+{
+    return (c & (8 | 2)) == 2;
+}
+
+/* Must a comparison be considered unsigned?  */
+static inline bool is_unsigned_cond(TCGCond c)
+{
+    return (c & (8 | 2)) == (8 | 2);
+}
+
+/* Must a comparison be considered a test?  */
+static inline bool is_tst_cond(TCGCond c)
+{
+    return (c | 1) == TCG_COND_TSTNE;
 }
 
 /* Create an "unsigned" version of a "signed" comparison.  */
 static inline TCGCond tcg_unsigned_cond(TCGCond c)
 {
-    return c & 2 ? (TCGCond)(c ^ 6) : c;
+    return is_signed_cond(c) ? (TCGCond)(c + 8) : c;
 }
 
 /* Create a "signed" version of an "unsigned" comparison.  */
 static inline TCGCond tcg_signed_cond(TCGCond c)
 {
-    return c & 4 ? (TCGCond)(c ^ 6) : c;
+    return is_unsigned_cond(c) ? (TCGCond)(c - 8) : c;
 }
 
-/* Must a comparison be considered unsigned?  */
-static inline bool is_unsigned_cond(TCGCond c)
+/* Create the eq/ne version of a tsteq/tstne comparison.  */
+static inline TCGCond tcg_tst_eqne_cond(TCGCond c)
+{
+    return is_tst_cond(c) ? (TCGCond)(c - 4) : c;
+}
+
+/* Create the lt/ge version of a tstne/tsteq comparison of the sign.  */
+static inline TCGCond tcg_tst_ltge_cond(TCGCond c)
 {
-    return (c & 4) != 0;
+    return is_tst_cond(c) ? (TCGCond)(c ^ 0xf) : c;
 }
 
 /*
@@ -92,7 +124,7 @@ static inline TCGCond tcg_high_cond(TCGCond c)
     case TCG_COND_LE:
     case TCG_COND_GEU:
     case TCG_COND_LEU:
-        return (TCGCond)(c ^ 8);
+        return (TCGCond)(c ^ (4 | 1));
     default:
         return c;
     }

tcg/tcg.c

@@ -2482,7 +2482,9 @@ static const char * const cond_name[] =
     [TCG_COND_LTU] = "ltu",
     [TCG_COND_GEU] = "geu",
     [TCG_COND_LEU] = "leu",
-    [TCG_COND_GTU] = "gtu"
+    [TCG_COND_GTU] = "gtu",
+    [TCG_COND_TSTEQ] = "tsteq",
+    [TCG_COND_TSTNE] = "tstne",
 };
 
 static const char * const ldst_name[(MO_BSWAP | MO_SSIZE) + 1] =