Commit 08b12bfb8f for qemu.org

commit 08b12bfb8f532dbc62e35c31d081ede1aa12098b
Author: Richard Henderson <richard.henderson@linaro.org>
Date:   Sun Jan 11 18:03:01 2026 +1100

    tcg/optimize: Fix a_mask computation for orc

    In computing a_mask, for or, we remove the bits from t1->o_mask
    which are known to be zero.  For orc, the bits known to be zero
    are the inverse of those known to be one.

    Cc: qemu-stable@nongnu.org
    Fixes: cc4033ee47c ("tcg/optimize: Build and use zero, one and affected bits in fold_orc")
    Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
    Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

diff --git a/tcg/optimize.c b/tcg/optimize.c
index 1f95da487b..db1d89396b 100644
--- a/tcg/optimize.c
+++ b/tcg/optimize.c
@@ -2360,7 +2360,7 @@ static bool fold_orc(OptContext *ctx, TCGOp *op)
     s_mask = t1->s_mask & t2->s_mask;

     /* Affected bits are those not known one, masked by those known one. */
-    a_mask = ~t1->o_mask & t2->o_mask;
+    a_mask = ~t1->o_mask & ~t2->o_mask;

     return fold_masks_zosa(ctx, op, z_mask, o_mask, s_mask, a_mask);
 }