diff --git a/src/intel/compiler/brw_builder.h b/src/intel/compiler/brw_builder.h
index fc2e708baa2..5e9eb977038 100644
--- a/src/intel/compiler/brw_builder.h
+++ b/src/intel/compiler/brw_builder.h
@@ -50,7 +50,14 @@ public:
    {
    }
 
-   explicit brw_builder(brw_shader *s) : brw_builder(s, s->dispatch_width) {}
+   /**
+    * Construct an brw_builder that inserts instructions into \p shader,
+    * using its dispatch width.
+    */
+   explicit brw_builder(brw_shader *s = NULL) :
+      brw_builder(s, s ? s->dispatch_width : 0)
+   {
+   }
 
    /**
     * Construct an brw_builder that inserts instructions before
diff --git a/src/intel/compiler/test_lower_scoreboard.cpp b/src/intel/compiler/test_lower_scoreboard.cpp
index 288e7d27ef6..48fdb70e185 100644
--- a/src/intel/compiler/test_lower_scoreboard.cpp
+++ b/src/intel/compiler/test_lower_scoreboard.cpp
@@ -42,7 +42,6 @@ protected:
 };
 
 scoreboard_test::scoreboard_test()
-   : bld(NULL, 0)
 {
    ctx = ralloc_context(NULL);
    compiler = rzalloc(ctx, struct brw_compiler);
diff --git a/src/intel/compiler/test_opt_cmod_propagation.cpp b/src/intel/compiler/test_opt_cmod_propagation.cpp
index f9cc7b091d3..d4e4edc4dc7 100644
--- a/src/intel/compiler/test_opt_cmod_propagation.cpp
+++ b/src/intel/compiler/test_opt_cmod_propagation.cpp
@@ -53,7 +53,6 @@ protected:
 };
 
 cmod_propagation_test::cmod_propagation_test()
-   : bld(NULL, 0)
 {
    ctx = ralloc_context(NULL);
    compiler = rzalloc(ctx, struct brw_compiler);
diff --git a/src/intel/compiler/test_opt_combine_constants.cpp b/src/intel/compiler/test_opt_combine_constants.cpp
index ec1efb2bb2e..7a6e065a143 100644
--- a/src/intel/compiler/test_opt_combine_constants.cpp
+++ b/src/intel/compiler/test_opt_combine_constants.cpp
@@ -68,7 +68,7 @@ struct FSCombineConstantsTest : public ::testing::Test {
 static brw_builder
 make_builder(brw_shader *s)
 {
-   return brw_builder(s, s->dispatch_width).at_end();
+   return brw_builder(s).at_end();
 }
 
 TEST_F(FSCombineConstantsTest, Simple)
diff --git a/src/intel/compiler/test_opt_copy_propagation.cpp b/src/intel/compiler/test_opt_copy_propagation.cpp
index 3b61f80f99a..430b67aa64d 100644
--- a/src/intel/compiler/test_opt_copy_propagation.cpp
+++ b/src/intel/compiler/test_opt_copy_propagation.cpp
@@ -42,7 +42,6 @@ protected:
 };
 
 copy_propagation_test::copy_propagation_test()
-   : bld(NULL, 0)
 {
    ctx = ralloc_context(NULL);
    compiler = rzalloc(ctx, struct brw_compiler);
diff --git a/src/intel/compiler/test_opt_cse.cpp b/src/intel/compiler/test_opt_cse.cpp
index 6f7633a6beb..edf117662dc 100644
--- a/src/intel/compiler/test_opt_cse.cpp
+++ b/src/intel/compiler/test_opt_cse.cpp
@@ -24,7 +24,6 @@ protected:
 };
 
 cse_test::cse_test()
-   : bld(NULL, 0)
 {
    ctx = ralloc_context(NULL);
    compiler = rzalloc(ctx, struct brw_compiler);
diff --git a/src/intel/compiler/test_opt_saturate_propagation.cpp b/src/intel/compiler/test_opt_saturate_propagation.cpp
index 1eb99c06fea..34e940015cd 100644
--- a/src/intel/compiler/test_opt_saturate_propagation.cpp
+++ b/src/intel/compiler/test_opt_saturate_propagation.cpp
@@ -42,7 +42,6 @@ protected:
 };
 
 saturate_propagation_test::saturate_propagation_test()
-   : bld(NULL, 0)
 {
    ctx = ralloc_context(NULL);
    compiler = rzalloc(ctx, struct brw_compiler);