tcg: Add TCG_OPF_NOT_PRESENT if TCG_TARGET_HAS_foo is negative

If INDEX_op_foo is always expanded by tcg_expand_vec_op, then
there may be no reasonable set of constraints to return from
tcg_target_op_def for that opcode.

Let TCG_TARGET_HAS_foo be specified as -1 in that case.  Thus a
boolean test for TCG_TARGET_HAS_foo is true, but we will not
assert within process_op_defs when no constraints are specified.

Compare this with tcg_can_emit_vec_op, which already uses this
tri-state indication.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

diff --git a/tcg/tcg-opc.h b/tcg/tcg-opc.h
index c7d971f..242d608 100644 (file)
--- a/tcg/tcg-opc.h
+++ b/tcg/tcg-opc.h
@@ -35,7 +35,7 @@ DEF(call, 0, 0, 3, TCG_OPF_CALL_CLOBBER | TCG_OPF_NOT_PRESENT)
 
 DEF(br, 0, 0, 1, TCG_OPF_BB_END)
 
-#define IMPL(X) (__builtin_constant_p(X) && !(X) ? TCG_OPF_NOT_PRESENT : 0)
+#define IMPL(X) (__builtin_constant_p(X) && (X) <= 0 ? TCG_OPF_NOT_PRESENT : 0)
 #if TCG_TARGET_REG_BITS == 32
 # define IMPL64  TCG_OPF_64BIT | TCG_OPF_NOT_PRESENT
 #else