tcg: Add TCG_COND_NEVER, TCG_COND_ALWAYS

There are several cases that can be handled easier inside both
translators and code generators if we have out-of-band values
for conditions.  It's easy enough to handle ALWAYS and NEVER in
the natural way inside the tcg middle-end.

Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>

1 files changed, 23 insertions, 14 deletions

diff --git a/tcg/tcg.h b/tcg/tcg.h
index 6ff2ab55be..75f0239709 100644
--- a/tcg/tcg.h
+++ b/tcg/tcg.h
@@ -266,18 +266,28 @@ typedef int TCGv_i64;
 #define TCG_CALL_DUMMY_TCGV     MAKE_TCGV_I32(-1)
 #define TCG_CALL_DUMMY_ARG      ((TCGArg)(-1))
 
+/* Conditions.  Note that these are layed out for easy manipulation by
+   the 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.  */
 typedef enum {
-    TCG_COND_EQ,
-    TCG_COND_NE,
-    TCG_COND_LT,
-    TCG_COND_GE,
-    TCG_COND_LE,
-    TCG_COND_GT,
+    /* non-signed */
+    TCG_COND_NEVER  = 0 | 0 | 0 | 0,
+    TCG_COND_ALWAYS = 0 | 0 | 0 | 1,
+    TCG_COND_EQ     = 8 | 0 | 0 | 0,
+    TCG_COND_NE     = 8 | 0 | 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,
     /* unsigned */
-    TCG_COND_LTU,
-    TCG_COND_GEU,
-    TCG_COND_LEU,
-    TCG_COND_GTU,
+    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,
 } TCGCond;
 
 /* Invert the sense of the comparison.  */
@@ -289,18 +299,17 @@ static inline TCGCond tcg_invert_cond(TCGCond c)
 /* Swap the operands in a comparison.  */
 static inline TCGCond tcg_swap_cond(TCGCond c)
 {
-    int mask = (c < TCG_COND_LT ? 0 : c < TCG_COND_LTU ? 7 : 15);
-    return (TCGCond)(c ^ mask);
+    return c & 6 ? (TCGCond)(c ^ 9) : c;
 }
 
 static inline TCGCond tcg_unsigned_cond(TCGCond c)
 {
-    return (c >= TCG_COND_LT && c <= TCG_COND_GT ? c + 4 : c);
+    return c & 2 ? (TCGCond)(c ^ 6) : c;
 }
 
 static inline bool is_unsigned_cond(TCGCond c)
 {
-    return c >= TCG_COND_LTU;
+    return (c & 4) != 0;
 }
 
 #define TEMP_VAL_DEAD  0