tcg/ppc: Add TCG_CT_CONST_CMP

Better constraint for tcg_out_cmp, based on the comparison.
We can't yet remove the fallback to load constants into a
scratch because of tcg_out_cmp2, but that path should not
be as frequent.

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

tcg/ppc/tcg-target-con-set.h

@@ -11,7 +11,7 @@
  */
 C_O0_I1(r)
 C_O0_I2(r, r)
-C_O0_I2(r, ri)
+C_O0_I2(r, rC)
 C_O0_I2(v, r)
 C_O0_I3(r, r, r)
 C_O0_I3(o, m, r)
@@ -26,13 +26,14 @@ C_O1_I2(r, rI, ri)
 C_O1_I2(r, rI, rT)
 C_O1_I2(r, r, r)
 C_O1_I2(r, r, ri)
+C_O1_I2(r, r, rC)
 C_O1_I2(r, r, rI)
 C_O1_I2(r, r, rT)
 C_O1_I2(r, r, rU)
 C_O1_I2(r, r, rZW)
 C_O1_I2(v, v, v)
 C_O1_I3(v, v, v, v)
-C_O1_I4(r, r, ri, rZ, rZ)
+C_O1_I4(r, r, rC, rZ, rZ)
 C_O1_I4(r, r, r, ri, ri)
 C_O2_I1(r, r, r)
 C_N1O1_I1(o, m, r)

tcg/ppc/tcg-target-con-str.h

@@ -16,6 +16,7 @@ REGS('v', ALL_VECTOR_REGS)
  * Define constraint letters for constants:
  * CONST(letter, TCG_CT_CONST_* bit set)
  */
+CONST('C', TCG_CT_CONST_CMP)
 CONST('I', TCG_CT_CONST_S16)
 CONST('M', TCG_CT_CONST_MONE)
 CONST('T', TCG_CT_CONST_S32)

tcg/ppc/tcg-target.c.inc

@@ -92,11 +92,13 @@
 #define SZR  (TCG_TARGET_REG_BITS / 8)
 
 #define TCG_CT_CONST_S16  0x100
+#define TCG_CT_CONST_U16  0x200
 #define TCG_CT_CONST_S32  0x400
 #define TCG_CT_CONST_U32  0x800
 #define TCG_CT_CONST_ZERO 0x1000
 #define TCG_CT_CONST_MONE 0x2000
 #define TCG_CT_CONST_WSZ  0x4000
+#define TCG_CT_CONST_CMP  0x8000
 
 #define ALL_GENERAL_REGS  0xffffffffu
 #define ALL_VECTOR_REGS   0xffffffff00000000ull
@@ -296,9 +298,35 @@ static bool tcg_target_const_match(int64_t sval, int ct,
         sval = (int32_t)sval;
     }
 
+    if (ct & TCG_CT_CONST_CMP) {
+        switch (cond) {
+        case TCG_COND_EQ:
+        case TCG_COND_NE:
+            ct |= TCG_CT_CONST_S16 | TCG_CT_CONST_U16;
+            break;
+        case TCG_COND_LT:
+        case TCG_COND_GE:
+        case TCG_COND_LE:
+        case TCG_COND_GT:
+            ct |= TCG_CT_CONST_S16;
+            break;
+        case TCG_COND_LTU:
+        case TCG_COND_GEU:
+        case TCG_COND_LEU:
+        case TCG_COND_GTU:
+            ct |= TCG_CT_CONST_U16;
+            break;
+        default:
+            g_assert_not_reached();
+        }
+    }
+
     if ((ct & TCG_CT_CONST_S16) && sval == (int16_t)sval) {
         return 1;
     }
+    if ((ct & TCG_CT_CONST_U16) && uval == (uint16_t)uval) {
+        return 1;
+    }
     if ((ct & TCG_CT_CONST_S32) && sval == (int32_t)sval) {
         return 1;
     }
@@ -1682,7 +1710,10 @@ static void tcg_out_cmp(TCGContext *s, int cond, TCGArg arg1, TCGArg arg2,
 
     tcg_debug_assert(TCG_TARGET_REG_BITS == 64 || type == TCG_TYPE_I32);
 
-    /* Simplify the comparisons below wrt CMPI.  */
+    /*
+     * Simplify the comparisons below wrt CMPI.
+     * All of the tests are 16-bit, so a 32-bit sign extend always works.
+     */
     if (type == TCG_TYPE_I32) {
         arg2 = (int32_t)arg2;
     }
@@ -3991,8 +4022,6 @@ static TCGConstraintSetIndex tcg_target_op_def(TCGOpcode op)
     case INDEX_op_sar_i32:
     case INDEX_op_rotl_i32:
     case INDEX_op_rotr_i32:
-    case INDEX_op_setcond_i32:
-    case INDEX_op_negsetcond_i32:
     case INDEX_op_and_i64:
     case INDEX_op_andc_i64:
     case INDEX_op_shl_i64:
@@ -4000,8 +4029,6 @@ static TCGConstraintSetIndex tcg_target_op_def(TCGOpcode op)
     case INDEX_op_sar_i64:
     case INDEX_op_rotl_i64:
     case INDEX_op_rotr_i64:
-    case INDEX_op_setcond_i64:
-    case INDEX_op_negsetcond_i64:
         return C_O1_I2(r, r, ri);
 
     case INDEX_op_mul_i32:
@@ -4045,11 +4072,16 @@ static TCGConstraintSetIndex tcg_target_op_def(TCGOpcode op)
 
     case INDEX_op_brcond_i32:
     case INDEX_op_brcond_i64:
-        return C_O0_I2(r, ri);
+        return C_O0_I2(r, rC);
-
+    case INDEX_op_setcond_i32:
+    case INDEX_op_setcond_i64:
+    case INDEX_op_negsetcond_i32:
+    case INDEX_op_negsetcond_i64:
+        return C_O1_I2(r, r, rC);
     case INDEX_op_movcond_i32:
     case INDEX_op_movcond_i64:
-        return C_O1_I4(r, r, ri, rZ, rZ);
+        return C_O1_I4(r, r, rC, rZ, rZ);
+
     case INDEX_op_deposit_i32:
     case INDEX_op_deposit_i64:
         return C_O1_I2(r, 0, rZ);