From 39f099ec9d6d420b6fe6f7f4f8ed80ae29c65ff2 Mon Sep 17 00:00:00 2001 From: Richard Henderson Date: Tue, 17 Jan 2017 12:02:08 -0800 Subject: [PATCH] tcg/i386: Always use TZCNT when available I think this is cleaner than sometimes using BSF. Signed-off-by: Richard Henderson --- tcg/i386/tcg-target.inc.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/tcg/i386/tcg-target.inc.c b/tcg/i386/tcg-target.inc.c index 6489b73862..5918008296 100644 --- a/tcg/i386/tcg-target.inc.c +++ b/tcg/i386/tcg-target.inc.c @@ -1143,10 +1143,14 @@ static void tcg_out_movcond64(TCGContext *s, TCGCond cond, TCGReg dest, static void tcg_out_ctz(TCGContext *s, int rexw, TCGReg dest, TCGReg arg1, TCGArg arg2, bool const_a2) { - if (const_a2) { - tcg_debug_assert(have_bmi1); - tcg_debug_assert(arg2 == (rexw ? 64 : 32)); + if (have_bmi1) { tcg_out_modrm(s, OPC_TZCNT + rexw, dest, arg1); + if (const_a2) { + tcg_debug_assert(arg2 == (rexw ? 64 : 32)); + } else { + tcg_debug_assert(dest != arg2); + tcg_out_cmov(s, TCG_COND_LTU, rexw, dest, arg2); + } } else { tcg_debug_assert(dest != arg2); tcg_out_modrm(s, OPC_BSF + rexw, dest, arg1); -- 2.11.4.GIT