[Qemu-devel] [PATCH 33/35] tcg-s390: Use the COMPARE IMMEDIATE instrucions for compares.

[Richard Henderson <rth@twiddle.net>]

These instructions are available with extended-immediate facility.

Signed-off-by: Richard Henderson <rth@twiddle.net>
---
 tcg/s390/tcg-target.c |   44 ++++++++++++++++++++++++++++++++++++++++++--
 1 files changed, 42 insertions(+), 2 deletions(-)

diff --git a/tcg/s390/tcg-target.c b/tcg/s390/tcg-target.c
index 8bc82b4..691a3f5 100644
--- a/tcg/s390/tcg-target.c
+++ b/tcg/s390/tcg-target.c
@@ -75,6 +75,10 @@ typedef enum S390Opcode {
     RIL_ALGFI   = 0xc20a,
     RIL_BRASL   = 0xc005,
     RIL_BRCL    = 0xc004,
+    RIL_CFI     = 0xc20d,
+    RIL_CGFI    = 0xc20c,
+    RIL_CLFI    = 0xc20f,
+    RIL_CLGFI   = 0xc20e,
     RIL_IIHF    = 0xc008,
     RIL_IILF    = 0xc009,
     RIL_LARL    = 0xc000,
@@ -533,7 +537,29 @@ static int tcg_match_xori(int ct, tcg_target_long val)
 
 static int tcg_match_cmpi(int ct, tcg_target_long val)
 {
-    return (val == 0);
+    if (facilities & FACILITY_EXT_IMM) {
+        /* The COMPARE IMMEDIATE instruction is available.  */
+        if (ct & TCG_CT_CONST_32) {
+            /* We have a 32-bit immediate and can compare against anything.  */
+            return 1;
+        } else {
+            /* ??? We have no insight here into whether the comparison is
+               signed or unsigned.  The COMPARE IMMEDIATE insn uses a 32-bit
+               signed immediate, and the COMPARE LOGICAL IMMEDIATE insn uses
+               a 32-bit unsigned immediate.  If we were to use the (semi)
+               obvious "val == (int32_t)val" we would be enabling unsigned
+               comparisons vs very large numbers.  The only solution is to
+               take the intersection of the ranges.  */
+            /* ??? Another possible solution is to simply lie and allow all
+               constants here and force the out-of-range values into a temp
+               register in tgen_cmp when we have knowledge of the actual
+               comparison code in use.  */
+            return val >= 0 && val <= 0x7fffffff;
+        }
+    } else {
+        /* Only the LOAD AND TEST instruction is available.  */
+        return val == 0;
+    }
 }
 
 /* Test if a constant matches the constraint. */
@@ -1093,7 +1119,21 @@ static int tgen_cmp(TCGContext *s, TCGType type, TCGCond c, TCGReg r1,
             }
             return tcg_cond_to_ltr_cond[c];
         } else {
-            tcg_abort();
+            if (c > TCG_COND_GT) {
+                /* unsigned */
+                if (type == TCG_TYPE_I32) {
+                    tcg_out_insn(s, RIL, CLFI, r1, c2);
+                } else {
+                    tcg_out_insn(s, RIL, CLGFI, r1, c2);
+                }
+            } else {
+                /* signed */
+                if (type == TCG_TYPE_I32) {
+                    tcg_out_insn(s, RIL, CFI, r1, c2);
+                } else {
+                    tcg_out_insn(s, RIL, CGFI, r1, c2);
+                }
+            }
         }
     } else {
         if (c > TCG_COND_GT) {
-- 
1.7.0.1