tcg/optimize: Simply some logical ops to NOT

Given, of course, an appropriate constant.  These could be generated
from the "canonical" operation for inversion on the guest, or via
other optimizations.

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Aurelien Jarno <aurelien@aurel32.net>
Signed-off-by: Richard Henderson <rth@twiddle.net>

diff --git a/tcg/optimize.c b/tcg/optimize.c
index 4bea8a56ef0aee6611b30c94da308da3f366065a..0b1dd13a63833de9b491298f4103aece0d85b525 100644 (file)
--- a/tcg/optimize.c
+++ b/tcg/optimize.c
@@ -655,6 +655,63 @@ static TCGArg *tcg_constant_folding(TCGContext *s, uint16_t *tcg_opc_ptr,
                 }
             }
             break;
+        CASE_OP_32_64(xor):
+        CASE_OP_32_64(nand):
+            if (temps[args[1]].state != TCG_TEMP_CONST
+                && temps[args[2]].state == TCG_TEMP_CONST
+                && temps[args[2]].val == -1) {
+                i = 1;
+                goto try_not;
+            }
+            break;
+        CASE_OP_32_64(nor):
+            if (temps[args[1]].state != TCG_TEMP_CONST
+                && temps[args[2]].state == TCG_TEMP_CONST
+                && temps[args[2]].val == 0) {
+                i = 1;
+                goto try_not;
+            }
+            break;
+        CASE_OP_32_64(andc):
+            if (temps[args[2]].state != TCG_TEMP_CONST
+                && temps[args[1]].state == TCG_TEMP_CONST
+                && temps[args[1]].val == -1) {
+                i = 2;
+                goto try_not;
+            }
+            break;
+        CASE_OP_32_64(orc):
+        CASE_OP_32_64(eqv):
+            if (temps[args[2]].state != TCG_TEMP_CONST
+                && temps[args[1]].state == TCG_TEMP_CONST
+                && temps[args[1]].val == 0) {
+                i = 2;
+                goto try_not;
+            }
+            break;
+        try_not:
+            {
+                TCGOpcode not_op;
+                bool have_not;
+
+                if (def->flags & TCG_OPF_64BIT) {
+                    not_op = INDEX_op_not_i64;
+                    have_not = TCG_TARGET_HAS_not_i64;
+                } else {
+                    not_op = INDEX_op_not_i32;
+                    have_not = TCG_TARGET_HAS_not_i32;
+                }
+                if (!have_not) {
+                    break;
+                }
+                s->gen_opc_buf[op_index] = not_op;
+                reset_temp(args[0]);
+                gen_args[0] = args[0];
+                gen_args[1] = args[i];
+                args += 3;
+                gen_args += 2;
+                continue;
+            }
         default:
             break;
         }