diff --git a/src/dec/frame.c b/src/dec/frame.c
index 911c7ffc..a37becf1 100644
--- a/src/dec/frame.c
+++ b/src/dec/frame.c
@@ -179,7 +179,7 @@ static int FinishRow(VP8Decoder* const dec, VP8Io* const io) {
     FilterRow(dec);
   }
 
-  if (io->put) {
+  if (io->put != NULL) {
     if (!first_row) {
       y_start -= extra_y_rows;
       io->y = ydst;
@@ -288,7 +288,7 @@ int VP8ProcessRow(VP8Decoder* const dec, VP8Io* const io) {
 VP8StatusCode VP8EnterCritical(VP8Decoder* const dec, VP8Io* const io) {
   // Call setup() first. This may trigger additional decoding features on 'io'.
   // Note: Afterward, we must call teardown() not matter what.
-  if (io->setup && !io->setup(io)) {
+  if (io->setup != NULL && !io->setup(io)) {
     VP8SetError(dec, VP8_STATUS_USER_ABORT, "Frame setup failed");
     return dec->status_;
   }
@@ -346,7 +346,7 @@ int VP8ExitCritical(VP8Decoder* const dec, VP8Io* const io) {
     ok = WebPWorkerSync(&dec->worker_);
   }
 
-  if (io->teardown) {
+  if (io->teardown != NULL) {
     io->teardown(io);
   }
   return ok;
diff --git a/src/dec/idec.c b/src/dec/idec.c
index 42d2a923..cb1b6693 100644
--- a/src/dec/idec.c
+++ b/src/dec/idec.c
@@ -268,7 +268,7 @@ static void RestoreContext(const MBContext* context, VP8Decoder* const dec,
 static VP8StatusCode IDecError(WebPIDecoder* const idec, VP8StatusCode error) {
   if (idec->state_ == STATE_VP8_DATA) {
     VP8Io* const io = &idec->io_;
-    if (io->teardown) {
+    if (io->teardown != NULL) {
       io->teardown(io);
     }
   }
@@ -574,7 +574,8 @@ WebPIDecoder* WebPINewDecoder(WebPDecBuffer* output_buffer) {
   VP8InitIo(&idec->io_);
 
   WebPResetDecParams(&idec->params_);
-  idec->params_.output = output_buffer ? output_buffer : &idec->output_;
+  idec->params_.output = (output_buffer != NULL) ? output_buffer
+                                                 : &idec->output_;
   WebPInitCustomIo(&idec->params_, &idec->io_);  // Plug the I/O functions.
 
   return idec;
diff --git a/src/dec/io.c b/src/dec/io.c
index 594804c2..67bd3bf5 100644
--- a/src/dec/io.c
+++ b/src/dec/io.c
@@ -601,7 +601,7 @@ static int CustomPut(const VP8Io* io) {
     return 0;
   }
   num_lines_out = p->emit(io, p);
-  if (p->emit_alpha) {
+  if (p->emit_alpha != NULL) {
     p->emit_alpha(io, p);
   }
   p->last_y += num_lines_out;
diff --git a/src/dec/vp8.c b/src/dec/vp8.c
index 253cb6b6..3b3ec690 100644
--- a/src/dec/vp8.c
+++ b/src/dec/vp8.c
@@ -766,9 +766,7 @@ void VP8Clear(VP8Decoder* const dec) {
   if (dec->use_threads_) {
     WebPWorkerEnd(&dec->worker_);
   }
-  if (dec->mem_) {
-    free(dec->mem_);
-  }
+  free(dec->mem_);
   dec->mem_ = NULL;
   dec->mem_size_ = 0;
   memset(&dec->br_, 0, sizeof(dec->br_));
diff --git a/src/dec/webp.c b/src/dec/webp.c
index aa3a703f..7de050d0 100644
--- a/src/dec/webp.c
+++ b/src/dec/webp.c
@@ -397,7 +397,7 @@ VP8StatusCode WebPParseHeaders(WebPHeaderStructure* const headers) {
 // WebPDecParams
 
 void WebPResetDecParams(WebPDecParams* const params) {
-  if (params) {
+  if (params != NULL) {
     memset(params, 0, sizeof(*params));
   }
 }