diff --git a/dlls/d3dcompiler_43/asmshader.l b/dlls/d3dcompiler_43/asmshader.l
index 0ba7e7a146a..581734473b3 100644
--- a/dlls/d3dcompiler_43/asmshader.l
+++ b/dlls/d3dcompiler_43/asmshader.l
@@ -98,7 +98,7 @@ NEWLINE                 (\n)|(\r\n)
 
 COMMA                   ","
 
-IMMVAL                  \-?(([0-9]+)|([0-9]*\.[0-9]+))(f)?
+IMMVAL                  \-?(([0-9]+\.?)|([0-9]*\.[0-9]+))(f)?
 
 ANY                     (.)
 
diff --git a/dlls/d3dcompiler_43/tests/asm.c b/dlls/d3dcompiler_43/tests/asm.c
index 08fff44f457..af5ad620757 100644
--- a/dlls/d3dcompiler_43/tests/asm.c
+++ b/dlls/d3dcompiler_43/tests/asm.c
@@ -127,6 +127,12 @@ static void ps_1_1_test(void) {
             "mov_d4 r0, r1\n",
             {0xffff0101, 0x00000001, 0x8e0f0000, 0x80e40001, 0x0000ffff}
         },
+        {   /* shader 2 */
+            "ps.1.1\n"
+            "def c2, 0, 0., 0, 0.\n",
+            {0xffff0101, 0x00000051, 0xa00f0002, 0x00000000, 0x00000000, 0x00000000,
+             0x00000000, 0x0000ffff}
+        },
     };
 
     exec_tests("ps_1_1", tests, sizeof(tests) / sizeof(tests[0]));