diff --git a/src/asahi/compiler/meson.build b/src/asahi/compiler/meson.build
index b397756b0fe..73c6b3dd616 100644
--- a/src/asahi/compiler/meson.build
+++ b/src/asahi/compiler/meson.build
@@ -106,6 +106,7 @@ if with_tests
     executable(
       'agx_tests',
       files(
+         'test/test-compact-constants.cpp',
          'test/test-minifloat.cpp',
          'test/test-optimizer.cpp',
          'test/test-lower-pseudo.cpp',
diff --git a/src/asahi/compiler/test/test-compact-constants.cpp b/src/asahi/compiler/test/test-compact-constants.cpp
new file mode 100644
index 00000000000..16848bc8a6d
--- /dev/null
+++ b/src/asahi/compiler/test/test-compact-constants.cpp
@@ -0,0 +1,57 @@
+/*
+ * Copyright 2021 Collabora, Ltd.
+ * SPDX-License-Identifier: MIT
+ */
+
+#include "agx_builder.h"
+#include "agx_compiler.h"
+#include "agx_test.h"
+
+#include <gtest/gtest.h>
+
+#define CASE(instr, expected, size)                                            \
+   INSTRUCTION_CASE(                                                           \
+      {                                                                        \
+         UNUSED agx_index out = agx_temp(b->shader, AGX_SIZE_##size);          \
+         instr;                                                                \
+         agx_unit_test(b, out);                                                \
+      },                                                                       \
+      {                                                                        \
+         UNUSED agx_index out = agx_temp(b->shader, AGX_SIZE_##size);          \
+         expected;                                                             \
+         agx_unit_test(b, out);                                                \
+      },                                                                       \
+      agx_opt_compact_constants)
+
+#define NEGCASE(instr, size)    CASE(instr, instr, size)
+#define CASE32(instr, expected) CASE(instr, expected, 32)
+#define NEGCASE32(instr)        NEGCASE(instr, 32)
+
+class CompactConstants : public testing::Test {
+ protected:
+   CompactConstants()
+   {
+      mem_ctx = ralloc_context(NULL);
+
+      wx = agx_register(0, AGX_SIZE_32);
+   }
+
+   ~CompactConstants()
+   {
+      ralloc_free(mem_ctx);
+   }
+
+   void *mem_ctx;
+   agx_index wx;
+};
+
+TEST_F(CompactConstants, FP32)
+{
+   CASE32(agx_fadd_to(b, out, wx, agx_mov_imm(b, 32, fui(32768.0))),
+          agx_fadd_to(b, out, wx, agx_mov_imm(b, 16, 0x7800)));
+}
+
+TEST_F(CompactConstants, InexactFP32)
+{
+   NEGCASE32(agx_fadd_to(b, out, wx, agx_mov_imm(b, 32, fui(32769.0))));
+}