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From: Dani Szebenyi <szedani@linux.ibm.com>
To: qemu-ppc@nongnu.org, qemu-devel@nongnu.org, richard.henderson@linaro.org
Cc: Dani Szebenyi <szedani@linux.ibm.com>,
	Ilya Leoshkevich <iii@linux.ibm.com>
Subject: [PATCH] tcg/ppc/tcg-target.c.inc: Fix tcg_out_rlw_rc
Date: Tue, 22 Oct 2024 15:34:39 +0200	[thread overview]
Message-ID: <20241022133535.69351-2-szedani@linux.ibm.com> (raw)

The previous message I sent was corrupted, sending again.

The TCG IR sequence:
mov_i32 tmp97,$0xc4240000                dead: 1  pref=0xffffffff
mov_i32 tmp98,$0x0                       pref=0xffffffff
rotr_i32 tmp97,tmp97,tmp98               dead: 1 2  pref=0xffffffff

was translated to `slwi	r15, r14, 0` instead of `slwi	r14, r14, 0` due to SH field overflow.

SH field is 5 bits, and tcg_out_rlw is called in some situations with `32-n`, when `n` is 0 it results in an overflow to RA field.

This commit prevents overflow of that field and adds debug assertions for the other fields

Acked-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Dani Szebenyi <szedani@linux.ibm.com>
---
 tcg/ppc/tcg-target.c.inc | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/tcg/ppc/tcg-target.c.inc b/tcg/ppc/tcg-target.c.inc
index 223f079524..9a11c26fd3 100644
--- a/tcg/ppc/tcg-target.c.inc
+++ b/tcg/ppc/tcg-target.c.inc
@@ -911,7 +911,9 @@ static void tcg_out_rld(TCGContext *s, int op, TCGReg ra, TCGReg rs,
 static void tcg_out_rlw_rc(TCGContext *s, int op, TCGReg ra, TCGReg rs,
                            int sh, int mb, int me, bool rc)
 {
-    tcg_out32(s, op | RA(ra) | RS(rs) | SH(sh) | MB(mb) | ME(me) | rc);
+    tcg_debug_assert((mb & 0x1f) == mb);
+    tcg_debug_assert((me & 0x1f) == me);
+    tcg_out32(s, op | RA(ra) | RS(rs) | SH(sh & 0x1f) | MB(mb) | ME(me) | rc);
 }
 
 static void tcg_out_rlw(TCGContext *s, int op, TCGReg ra, TCGReg rs,
-- 
2.47.0



             reply	other threads:[~2024-10-22 13:49 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-10-22 13:34 Dani Szebenyi [this message]
2024-10-22 18:19 ` [PATCH] tcg/ppc/tcg-target.c.inc: Fix tcg_out_rlw_rc Richard Henderson
  -- strict thread matches above, loose matches on Subject: below --
2024-10-22 12:14 Dani Szebenyi

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