diff --git a/libavcodec/aacdec.h b/libavcodec/aacdec.h
index e8d3297d17..e5165e9b54 100644
--- a/libavcodec/aacdec.h
+++ b/libavcodec/aacdec.h
@@ -67,6 +67,9 @@ enum CouplingPoint {
     AFTER_IMDCT = 3,
 };
 
+// Supposed to be equal to AAC_RENAME() in case of USE_FIXED.
+#define RENAME_FIXED(name) name ## _fixed
+
 /**
  * Long Term Prediction
  */
@@ -227,11 +230,10 @@ typedef struct AACDecContext {
     av_tx_fn mdct960_fn;
     av_tx_fn mdct1024_fn;
     av_tx_fn mdct_ltp_fn;
-#if USE_FIXED
-    AVFixedDSPContext *fdsp;
-#else
-    AVFloatDSPContext *fdsp;
-#endif /* USE_FIXED */
+    union {
+        AVFixedDSPContext *RENAME_FIXED(fdsp);
+        AVFloatDSPContext *fdsp;
+    };
     int random_state;
     /** @} */
 
@@ -272,6 +274,10 @@ typedef struct AACDecContext {
     void (*subband_scale)(int *dst, int *src, int scale, int offset, int len, void *log_context);
 } AACDecContext;
 
+#if defined(USE_FIXED) && USE_FIXED
+#define fdsp          RENAME_FIXED(fdsp)
+#endif
+
 void ff_aacdec_init_mips(AACDecContext *c);
 
 #endif /* AVCODEC_AACDEC_H */