From: Richard Henderson <richard.henderson@linaro.org>
Date: Fri, 3 Jan 2025 19:08:44 +0000 (-0800)
Subject: tcg: Add TCG_OPF_NOT_PRESENT to opcodes without inputs or outputs
X-Git-Tag: v10.0.0-rc0~82^2~28
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=07ffd5b219681d9f6eb6bef9f66152bb88b23106;p=thirdparty%2Fqemu.git

tcg: Add TCG_OPF_NOT_PRESENT to opcodes without inputs or outputs

The br, mb, goto_tb and exit_tb opcodes do not have
register operands, only constants, flags, or labels.
Remove the special case in opcode_args_ct by including
TCG_OPF_NOT_PRESENT in the flags for these opcodes.

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

diff --git a/include/tcg/tcg-opc.h b/include/tcg/tcg-opc.h
index 14aff6e7f92..724e7a9de8c 100644
--- a/include/tcg/tcg-opc.h
+++ b/include/tcg/tcg-opc.h
@@ -33,7 +33,7 @@ DEF(set_label, 0, 0, 1, TCG_OPF_BB_END | TCG_OPF_NOT_PRESENT)
 /* variable number of parameters */
 DEF(call, 0, 0, 3, TCG_OPF_CALL_CLOBBER | TCG_OPF_NOT_PRESENT)
 
-DEF(br, 0, 0, 1, TCG_OPF_BB_END)
+DEF(br, 0, 0, 1, TCG_OPF_BB_END | TCG_OPF_NOT_PRESENT)
 
 #define IMPL(X) (__builtin_constant_p(X) && (X) <= 0 ? TCG_OPF_NOT_PRESENT : 0)
 #if TCG_TARGET_REG_BITS == 32
@@ -42,7 +42,7 @@ DEF(br, 0, 0, 1, TCG_OPF_BB_END)
 # define IMPL64  TCG_OPF_64BIT
 #endif
 
-DEF(mb, 0, 0, 1, 0)
+DEF(mb, 0, 0, 1, TCG_OPF_NOT_PRESENT)
 
 DEF(mov_i32, 1, 1, 0, TCG_OPF_NOT_PRESENT)
 DEF(setcond_i32, 1, 2, 1, 0)
@@ -193,8 +193,8 @@ DEF(mulsh_i64, 1, 2, 0, IMPL64 | IMPL(TCG_TARGET_HAS_mulsh_i64))
 /* There are tcg_ctx->insn_start_words here, not just one. */
 DEF(insn_start, 0, 0, DATA64_ARGS, TCG_OPF_NOT_PRESENT)
 
-DEF(exit_tb, 0, 0, 1, TCG_OPF_BB_EXIT | TCG_OPF_BB_END)
-DEF(goto_tb, 0, 0, 1, TCG_OPF_BB_EXIT | TCG_OPF_BB_END)
+DEF(exit_tb, 0, 0, 1, TCG_OPF_BB_EXIT | TCG_OPF_BB_END | TCG_OPF_NOT_PRESENT)
+DEF(goto_tb, 0, 0, 1, TCG_OPF_BB_EXIT | TCG_OPF_BB_END | TCG_OPF_NOT_PRESENT)
 DEF(goto_ptr, 0, 1, 0, TCG_OPF_BB_EXIT | TCG_OPF_BB_END)
 
 DEF(plugin_cb, 0, 0, 1, TCG_OPF_NOT_PRESENT)
diff --git a/tcg/tcg.c b/tcg/tcg.c
index b9119a1ec71..e9ecdc5eeb2 100644
--- a/tcg/tcg.c
+++ b/tcg/tcg.c
@@ -3371,9 +3371,6 @@ static const TCGArgConstraint *opcode_args_ct(const TCGOp *op)
     assert(tcg_op_supported(op->opc, TCGOP_TYPE(op), TCGOP_FLAGS(op)));
 #endif
 
-    if (def->nb_iargs + def->nb_oargs == 0) {
-        return NULL;
-    }
     if (def->flags & TCG_OPF_NOT_PRESENT) {
         return empty_cts;
     }