tcg/optimize: Build and use one and affected bits in fold_or

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 d22396f6d723e245e5d916d98abb24fd7462a240..ce065d0e22421dfed6c917f3d153e02e96f336bb 100644 (file)
--- a/tcg/optimize.c
+++ b/tcg/optimize.c
@@ -2263,7 +2263,7 @@ static bool fold_not(OptContext *ctx, TCGOp *op)
 
 static bool fold_or(OptContext *ctx, TCGOp *op)
 {
-    uint64_t z_mask, s_mask;
+    uint64_t z_mask, o_mask, s_mask, a_mask;
     TempOptInfo *t1, *t2;
 
     if (fold_const2_commutative(ctx, op) ||
@@ -2274,9 +2274,15 @@ static bool fold_or(OptContext *ctx, TCGOp *op)
 
     t1 = arg_info(op->args[1]);
     t2 = arg_info(op->args[2]);
+
     z_mask = t1->z_mask | t2->z_mask;
+    o_mask = t1->o_mask | t2->o_mask;
     s_mask = t1->s_mask & t2->s_mask;
-    return fold_masks_zs(ctx, op, z_mask, s_mask);
+
+    /* Affected bits are those not known one, masked by those known zero. */
+    a_mask = ~t1->o_mask & t2->z_mask;
+
+    return fold_masks_zosa(ctx, op, z_mask, o_mask, s_mask, a_mask);
 }
 
 static bool fold_orc(OptContext *ctx, TCGOp *op)