diff --git a/src/dmd/backend/cg87.d b/src/dmd/backend/cg87.d
index b05dd007d927..429693e1755b 100644
--- a/src/dmd/backend/cg87.d
+++ b/src/dmd/backend/cg87.d
@@ -3646,6 +3646,20 @@ void fixresult_complex87(ref CodeBuilder cdb,elem *e,regm_t retregs,regm_t *pret
         cdb.genf2(0xDD,modregrm(3,3,0));        // FPOP
         pop87();
     }
+    else if (tym == TYllong)
+    {
+        // passing cfloat through register for I64
+        assert(retregs & mST01, "this float expression is not implemented");
+        pop87();
+        cdb.genfltreg(ESC(MFfloat,1),BX,4);     // FSTP floatreg
+        pop87();
+        cdb.genfltreg(ESC(MFfloat,1),BX,0);     // FSTP floatreg+4
+        genfwait(cdb);
+        const reg = findreg(*pretregs);
+        getregs(cdb,reg);
+        cdb.genfltreg(LOD, reg, 0);             // MOV ECX,floatreg
+        code_orrex(cdb.last(), REX_W);          // extend to RCX
+    }
     else if (tym == TYcfloat && *pretregs & (mAX|mDX) && retregs & mST01)
     {
         if (*pretregs & mPSW && !(retregs & mPSW))
diff --git a/src/dmd/backend/cod2.d b/src/dmd/backend/cod2.d
index e178916b9c2e..78a00bb4d09c 100644
--- a/src/dmd/backend/cod2.d
+++ b/src/dmd/backend/cod2.d
@@ -924,7 +924,8 @@ void cdmul(ref CodeBuilder cdb,elem *e,regm_t *pretregs)
             config.fpxmmregs && oper != OPmod && tyxmmreg(tyml) &&
             !(*pretregs & mST0) &&
             !(ty == TYldouble || ty == TYildouble) &&  // watch out for shrinkLongDoubleConstantIfPossible()
-            !tycomplex(ty) // SIMD code is not set up to deal with complex mul/div
+            !tycomplex(ty) && // SIMD code is not set up to deal with complex mul/div
+            !(ty == TYllong)  //   or passing to function through integer register
            )
         {
             orthxmm(cdb,e,pretregs);
diff --git a/test/runnable/test18772.d b/test/runnable/test18772.d
index cc99bb2446c4..d818a3c80932 100644
--- a/test/runnable/test18772.d
+++ b/test/runnable/test18772.d
@@ -1,13 +1,94 @@
-float fun(cfloat z)
+float getreal_rcx(cfloat z)
 {
     return z.re;
 }
+float getimag_rcx(cfloat z)
+{
+    return z.im;
+}
 
-void main()
+float getreal_rdx(cfloat z, int)
+{
+    return z.re;
+}
+float getimag_rdx(cfloat z, int)
+{
+    return z.im;
+}
+
+float getreal_r8(cfloat z, int, int)
+{
+    return z.re;
+}
+float getimag_r8(cfloat z, int, int)
+{
+    return z.im;
+}
+
+float getreal_r9(cfloat z, int, int, int)
+{
+    return z.re;
+}
+float getimag_r9(cfloat z, int, int, int)
+{
+    return z.im;
+}
+
+float getreal_stack(cfloat z, int, int, int, int)
+{
+    return z.re;
+}
+float getimag_stack(cfloat z, int, int, int, int)
+{
+    return z.im;
+}
+
+void test18772()
 {
     cfloat[1] A;
     float[1] B;
     int i = 0;
-    version(D_LP64) {} else // disabled because of wrong codegen: https://issues.dlang.org/show_bug.cgi?id=20089
-    double C = fun(A[i] * B[i]);
+    A[0] = 2.0f + 4i;
+    B[0] = 3.0f;
+    assert(6.0 == getreal_rcx(A[i] * B[i]));
+    assert(12.0 == getimag_rcx(A[i] * B[i]));
+
+    assert(6.0 == getreal_rdx(A[i] * B[i], 1));
+    assert(12.0 == getimag_rdx(A[i] * B[i], 1));
+
+    assert(6.0 == getreal_r8(A[i] * B[i], 1, 2));
+    assert(12.0 == getimag_r8(A[i] * B[i], 1, 2));
+
+    assert(6.0 == getreal_r9(A[i] * B[i], 1, 2, 3));
+    assert(12.0 == getimag_r9(A[i] * B[i], 1, 2, 3));
+
+    assert(6.0 == getreal_stack(A[i] * B[i], 1, 2, 3, 4));
+    assert(12.0 == getimag_stack(A[i] * B[i], 1, 2, 3, 4));
+}
+
+void test(T)()
+{
+    static auto getre0(T z)
+    {
+        return z.re;
+    }
+    static auto getim0(T z)
+    {
+        return z.im;
+    }
+    
+    T z = 3 + 4i;
+    auto d = z.re;
+    
+    assert(getre0(d * z) == d * 3);
+    assert(getim0(d * z) == d * 4);
+}
+
+void main()
+{
+    test18772();
+
+    test!cfloat();
+    test!cdouble();
+    test!creal();
 }