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From: Paolo Bonzini <pbonzini@redhat.com>
To: qemu-devel@nongnu.org
Cc: richard.henderson@linaro.org, zhao1.liu@intel.com
Subject: [PATCH v2 04/25] target/i386: cc_op is not dynamic in gen_jcc1
Date: Mon,  6 May 2024 10:09:36 +0200	[thread overview]
Message-ID: <20240506080957.10005-5-pbonzini@redhat.com> (raw)
In-Reply-To: <20240506080957.10005-1-pbonzini@redhat.com>

Resetting cc_op to CC_OP_DYNAMIC should be done at control flow junctions,
which is not the case here.  This translation block is ending and the
only effect of calling set_cc_op() would be a discard of s->cc_srcT.
This discard is useless (it's a temporary, not a global) and in fact
prevents gen_prepare_cc from returning s->cc_srcT.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 target/i386/tcg/translate.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/target/i386/tcg/translate.c b/target/i386/tcg/translate.c
index 9aecd415b38..3f1d2858fc9 100644
--- a/target/i386/tcg/translate.c
+++ b/target/i386/tcg/translate.c
@@ -1227,13 +1227,13 @@ static inline void gen_jcc1_noeob(DisasContext *s, int b, TCGLabel *l1)
 
 /* Generate a conditional jump to label 'l1' according to jump opcode
    value 'b'. In the fast case, T0 is guaranteed not to be used.
-   A translation block must end soon.  */
+   One or both of the branches will call gen_jmp_rel, so ensure
+   cc_op is clean.  */
 static inline void gen_jcc1(DisasContext *s, int b, TCGLabel *l1)
 {
     CCPrepare cc = gen_prepare_cc(s, b, s->T0);
 
     gen_update_cc_op(s);
-    set_cc_op(s, CC_OP_DYNAMIC);
     if (cc.use_reg2) {
         tcg_gen_brcond_tl(cc.cond, cc.reg, cc.reg2, l1);
     } else {
-- 
2.45.0



  parent reply	other threads:[~2024-05-06  8:12 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-05-06  8:09 [PATCH v2 00/25] target/i386: convert 1-byte opcodes to new decoder Paolo Bonzini
2024-05-06  8:09 ` [PATCH v2 01/25] target/i386: use TSTEQ/TSTNE to test low bits Paolo Bonzini
2024-05-06  8:09 ` [PATCH v2 02/25] target/i386: use TSTEQ/TSTNE to check flags Paolo Bonzini
2024-05-06  8:09 ` [PATCH v2 03/25] target/i386: remove mask from CCPrepare Paolo Bonzini
2024-05-06  8:09 ` Paolo Bonzini [this message]
2024-05-06 15:53   ` [PATCH v2 04/25] target/i386: cc_op is not dynamic in gen_jcc1 Richard Henderson
2024-05-06  8:09 ` [PATCH v2 05/25] target/i386: cleanup cc_op changes for REP/REPZ/REPNZ Paolo Bonzini
2024-05-06 16:07   ` Richard Henderson
2024-05-06 16:31     ` Paolo Bonzini
2024-05-06 16:39       ` Richard Henderson
2024-05-06  8:09 ` [PATCH v2 06/25] target/i386: pull cc_op update to callers of gen_jmp_rel{, _csize} Paolo Bonzini
2024-05-06 16:12   ` [PATCH v2 06/25] target/i386: pull cc_op update to callers of gen_jmp_rel{,_csize} Richard Henderson
2024-05-06  8:09 ` [PATCH v2 07/25] target/i386: extend cc_* when using them to compute flags Paolo Bonzini
2024-05-06 16:16   ` Richard Henderson
2024-05-06  8:09 ` [PATCH v2 08/25] target/i386: do not use s->T0 and s->T1 as scratch registers for CCPrepare Paolo Bonzini
2024-05-06 16:18   ` Richard Henderson
2024-05-06  8:09 ` [PATCH v2 09/25] target/i386: clarify the "reg" argument of functions returning CCPrepare Paolo Bonzini
2024-05-06 16:19   ` Richard Henderson
2024-05-06  8:09 ` [PATCH v2 10/25] target/i386: cleanup *gen_eob* Paolo Bonzini
2024-05-06 16:21   ` Richard Henderson
2024-05-06  8:09 ` [PATCH v2 11/25] target/i386: reintroduce debugging mechanism Paolo Bonzini
2024-05-06 16:23   ` Richard Henderson
2024-05-06  8:09 ` [PATCH v2 12/25] target/i386: move 00-5F opcodes to new decoder Paolo Bonzini
2024-05-06  8:09 ` [PATCH v2 13/25] target/i386: extract gen_far_call/jmp, reordering temporaries Paolo Bonzini
2024-05-06  8:09 ` [PATCH v2 14/25] target/i386: allow instructions with more than one immediate Paolo Bonzini
2024-05-06  8:09 ` [PATCH v2 15/25] target/i386: move 60-BF opcodes to new decoder Paolo Bonzini
2024-05-06 16:44   ` Richard Henderson
2024-05-06  8:09 ` [PATCH v2 16/25] target/i386: generalize gen_movl_seg_T0 Paolo Bonzini
2024-05-06  8:09 ` [PATCH v2 17/25] target/i386: move C0-FF opcodes to new decoder (except for x87) Paolo Bonzini
2024-05-06 16:56   ` Richard Henderson
2024-05-06  8:09 ` [PATCH v2 18/25] target/i386: merge and enlarge a few ranges for call to disas_insn_new Paolo Bonzini
2024-05-06  8:09 ` [PATCH v2 19/25] target/i386: move remaining conditional operations to new decoder Paolo Bonzini
2024-05-06  8:09 ` [PATCH v2 20/25] target/i386: move BSWAP " Paolo Bonzini
2024-05-06  8:09 ` [PATCH v2 21/25] target/i386: port extensions of one-byte opcodes " Paolo Bonzini
2024-05-06  8:09 ` [PATCH v2 22/25] target/i386: remove now-converted opcodes from old decoder Paolo Bonzini
2024-05-06  8:09 ` [PATCH v2 23/25] target/i386: decode x87 instructions in a separate function Paolo Bonzini
2024-05-06  8:09 ` [PATCH v2 24/25] target/i386: split legacy decoder into " Paolo Bonzini
2024-05-06  8:09 ` [PATCH v2 25/25] target/i386: remove duplicate prefix decoding Paolo Bonzini

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