From f6a82f8efadc1650ae4cb5648c8d3fb4dfca53ea Mon Sep 17 00:00:00 2001
From: hrkrshnn <webmail.hari@gmail.com>
Date: Mon, 29 Mar 2021 11:18:53 +0200
Subject: [PATCH] Yul tests for MemoryStoreRemover

---
 .../memoryStoreRemover/calldatasize.yul       | 21 ++++++++++++
 .../memoryStoreRemover/complex1.yul           | 21 ++++++++++++
 .../memoryStoreRemover/complex2.yul           | 32 +++++++++++++++++++
 .../memoryStoreRemover/complex3.yul           | 25 +++++++++++++++
 .../memoryStoreRemover/complex4.yul           | 23 +++++++++++++
 .../memoryStoreRemover/complex5.yul           | 22 +++++++++++++
 .../memoryStoreRemover/complex6.yul           | 22 +++++++++++++
 .../memoryStoreRemover/complex7.yul           | 22 +++++++++++++
 .../memoryStoreRemover/complex8.yul           | 19 +++++++++++
 .../memoryStoreRemover/complex9.yul           | 16 ++++++++++
 .../memoryStoreRemover/eip1985.yul            | 19 +++++++++++
 .../memoryStoreRemover/msize.yul              | 15 +++++++++
 .../memoryStoreRemover/overflow.yul           | 20 ++++++++++++
 .../memoryStoreRemover/overflow_mstore.yul    | 19 +++++++++++
 .../memoryStoreRemover/simple1.yul            | 13 ++++++++
 .../memoryStoreRemover/simple10.yul           | 29 +++++++++++++++++
 .../memoryStoreRemover/simple2.yul            | 17 ++++++++++
 .../memoryStoreRemover/simple3.yul            | 17 ++++++++++
 .../memoryStoreRemover/simple4.yul            | 19 +++++++++++
 .../memoryStoreRemover/simple5.yul            | 19 +++++++++++
 .../memoryStoreRemover/simple6.yul            | 21 ++++++++++++
 .../memoryStoreRemover/simple7.yul            | 19 +++++++++++
 .../memoryStoreRemover/simple8.yul            | 21 ++++++++++++
 .../memoryStoreRemover/simple9.yul            | 24 ++++++++++++++
 .../memoryStoreRemover/smoke.yul              |  5 +++
 25 files changed, 500 insertions(+)
 create mode 100644 test/libyul/yulOptimizerTests/memoryStoreRemover/calldatasize.yul
 create mode 100644 test/libyul/yulOptimizerTests/memoryStoreRemover/complex1.yul
 create mode 100644 test/libyul/yulOptimizerTests/memoryStoreRemover/complex2.yul
 create mode 100644 test/libyul/yulOptimizerTests/memoryStoreRemover/complex3.yul
 create mode 100644 test/libyul/yulOptimizerTests/memoryStoreRemover/complex4.yul
 create mode 100644 test/libyul/yulOptimizerTests/memoryStoreRemover/complex5.yul
 create mode 100644 test/libyul/yulOptimizerTests/memoryStoreRemover/complex6.yul
 create mode 100644 test/libyul/yulOptimizerTests/memoryStoreRemover/complex7.yul
 create mode 100644 test/libyul/yulOptimizerTests/memoryStoreRemover/complex8.yul
 create mode 100644 test/libyul/yulOptimizerTests/memoryStoreRemover/complex9.yul
 create mode 100644 test/libyul/yulOptimizerTests/memoryStoreRemover/eip1985.yul
 create mode 100644 test/libyul/yulOptimizerTests/memoryStoreRemover/msize.yul
 create mode 100644 test/libyul/yulOptimizerTests/memoryStoreRemover/overflow.yul
 create mode 100644 test/libyul/yulOptimizerTests/memoryStoreRemover/overflow_mstore.yul
 create mode 100644 test/libyul/yulOptimizerTests/memoryStoreRemover/simple1.yul
 create mode 100644 test/libyul/yulOptimizerTests/memoryStoreRemover/simple10.yul
 create mode 100644 test/libyul/yulOptimizerTests/memoryStoreRemover/simple2.yul
 create mode 100644 test/libyul/yulOptimizerTests/memoryStoreRemover/simple3.yul
 create mode 100644 test/libyul/yulOptimizerTests/memoryStoreRemover/simple4.yul
 create mode 100644 test/libyul/yulOptimizerTests/memoryStoreRemover/simple5.yul
 create mode 100644 test/libyul/yulOptimizerTests/memoryStoreRemover/simple6.yul
 create mode 100644 test/libyul/yulOptimizerTests/memoryStoreRemover/simple7.yul
 create mode 100644 test/libyul/yulOptimizerTests/memoryStoreRemover/simple8.yul
 create mode 100644 test/libyul/yulOptimizerTests/memoryStoreRemover/simple9.yul
 create mode 100644 test/libyul/yulOptimizerTests/memoryStoreRemover/smoke.yul

diff --git a/test/libyul/yulOptimizerTests/memoryStoreRemover/calldatasize.yul b/test/libyul/yulOptimizerTests/memoryStoreRemover/calldatasize.yul
new file mode 100644
index 000000000..f6a5a1a6b
--- /dev/null
+++ b/test/libyul/yulOptimizerTests/memoryStoreRemover/calldatasize.yul
@@ -0,0 +1,21 @@
+// Test to see if the solver can prove that there is no overflow
+// during memory calculations.
+{
+    let x := 0
+    let y := 100
+    // can be removed
+    mstore(x, y)
+    // reads from [500, 500 + calldatasize())
+    // since `500 + calldatasize()` does not overflow, it does not read from [0, 32)
+    // Assuming EIP 1985, the value of calldatasize is at most 2**32.
+    pop(staticcall(10000, 0, 500, calldatasize(), 0, 0))
+}
+// ----
+// step: memoryStoreRemover
+//
+// {
+//     let x := 0
+//     let y := 100
+//     pop(y)
+//     pop(staticcall(10000, 0, 500, calldatasize(), 0, 0))
+// }
diff --git a/test/libyul/yulOptimizerTests/memoryStoreRemover/complex1.yul b/test/libyul/yulOptimizerTests/memoryStoreRemover/complex1.yul
new file mode 100644
index 000000000..fbaa462e1
--- /dev/null
+++ b/test/libyul/yulOptimizerTests/memoryStoreRemover/complex1.yul
@@ -0,0 +1,21 @@
+{
+    let x := 10
+    let y := 100
+    if calldataload(0) {
+       // should be removed
+       mstore(x, y)
+    }
+
+    if calldataload(0) {
+       pop(mload(y))
+    }
+}
+// ----
+// step: memoryStoreRemover
+//
+// {
+//     let x := 10
+//     let y := 100
+//     if calldataload(0) { pop(y) }
+//     if calldataload(0) { pop(mload(y)) }
+// }
diff --git a/test/libyul/yulOptimizerTests/memoryStoreRemover/complex2.yul b/test/libyul/yulOptimizerTests/memoryStoreRemover/complex2.yul
new file mode 100644
index 000000000..f4c53aa18
--- /dev/null
+++ b/test/libyul/yulOptimizerTests/memoryStoreRemover/complex2.yul
@@ -0,0 +1,32 @@
+{
+    f()
+    let z := 100
+    pop(mload(z))
+
+    if calldataload(0) {
+        // does not read from location [20, 52)
+        pop(keccak256(z, z))
+    }
+
+    function f() {
+        let x := 10
+        let y := 20
+        // can be removed
+        mstore(x, y)
+    }
+}
+// ----
+// step: memoryStoreRemover
+//
+// {
+//     f()
+//     let z := 100
+//     pop(mload(z))
+//     if calldataload(0) { pop(keccak256(z, z)) }
+//     function f()
+//     {
+//         let x := 10
+//         let y := 20
+//         pop(y)
+//     }
+// }
diff --git a/test/libyul/yulOptimizerTests/memoryStoreRemover/complex3.yul b/test/libyul/yulOptimizerTests/memoryStoreRemover/complex3.yul
new file mode 100644
index 000000000..92fbd4b56
--- /dev/null
+++ b/test/libyul/yulOptimizerTests/memoryStoreRemover/complex3.yul
@@ -0,0 +1,25 @@
+{
+    let x := 32
+    let y := 100
+    // can be removed
+    mstore(x, y)
+    if calldataload(0) {
+       let cds := calldatasize()
+       // Reads from [0, 32), so does not invalidate location x!
+       pop(call(1000, 0, 100, 0, 32, 64, 0))
+    }
+
+}
+// ----
+// step: memoryStoreRemover
+//
+// {
+//     let x := 32
+//     let y := 100
+//     pop(y)
+//     if calldataload(0)
+//     {
+//         let cds := calldatasize()
+//         pop(call(1000, 0, 100, 0, 32, 64, 0))
+//     }
+// }
diff --git a/test/libyul/yulOptimizerTests/memoryStoreRemover/complex4.yul b/test/libyul/yulOptimizerTests/memoryStoreRemover/complex4.yul
new file mode 100644
index 000000000..ee1183435
--- /dev/null
+++ b/test/libyul/yulOptimizerTests/memoryStoreRemover/complex4.yul
@@ -0,0 +1,23 @@
+{
+    let x := 32
+    let y := 100
+    // cannot be removed
+    mstore(x, y)
+    let i := 1
+    for {} lt(i, 10) {i := add(i, 1) } {
+        // does not read from i, however, we cannot infer this. So, the above mstore
+        // cannot be removed.
+        pop(mload(i))
+    }
+}
+// ----
+// step: memoryStoreRemover
+//
+// {
+//     let x := 32
+//     let y := 100
+//     mstore(x, y)
+//     let i := 1
+//     for { } lt(i, 10) { i := add(i, 1) }
+//     { pop(mload(i)) }
+// }
diff --git a/test/libyul/yulOptimizerTests/memoryStoreRemover/complex5.yul b/test/libyul/yulOptimizerTests/memoryStoreRemover/complex5.yul
new file mode 100644
index 000000000..31ffb8ff5
--- /dev/null
+++ b/test/libyul/yulOptimizerTests/memoryStoreRemover/complex5.yul
@@ -0,0 +1,22 @@
+{
+    let x := 0
+    let y := 50
+    // cannot be removed, since z is not in SSA form
+    mstore(x, y)
+
+    let z := 200
+    // z is not in SSA form, so the solver would use a free variable.
+    z := 100
+    pop(mload(z))
+}
+// ----
+// step: memoryStoreRemover
+//
+// {
+//     let x := 0
+//     let y := 50
+//     mstore(x, y)
+//     let z := 200
+//     z := 100
+//     pop(mload(z))
+// }
diff --git a/test/libyul/yulOptimizerTests/memoryStoreRemover/complex6.yul b/test/libyul/yulOptimizerTests/memoryStoreRemover/complex6.yul
new file mode 100644
index 000000000..dfa259214
--- /dev/null
+++ b/test/libyul/yulOptimizerTests/memoryStoreRemover/complex6.yul
@@ -0,0 +1,22 @@
+{
+    let x := 0
+    let y := 10
+    let i := 0
+    for {} iszero(i) {i := add(i, 1)}
+    {
+        // can be removed!
+        mstore(x, i)
+    }
+    pop(mload(200))
+}
+// ----
+// step: memoryStoreRemover
+//
+// {
+//     let x := 0
+//     let y := 10
+//     let i := 0
+//     for { } iszero(i) { i := add(i, 1) }
+//     { pop(i) }
+//     pop(mload(200))
+// }
diff --git a/test/libyul/yulOptimizerTests/memoryStoreRemover/complex7.yul b/test/libyul/yulOptimizerTests/memoryStoreRemover/complex7.yul
new file mode 100644
index 000000000..2c4e41715
--- /dev/null
+++ b/test/libyul/yulOptimizerTests/memoryStoreRemover/complex7.yul
@@ -0,0 +1,22 @@
+{
+    let x := 0
+    let y := 10
+    let i := 0
+    for {} iszero(i) {i := add(i, 1)}
+    {
+        // cannot be removed!
+        mstore(i, y)
+    }
+    pop(mload(200))
+}
+// ----
+// step: memoryStoreRemover
+//
+// {
+//     let x := 0
+//     let y := 10
+//     let i := 0
+//     for { } iszero(i) { i := add(i, 1) }
+//     { mstore(i, y) }
+//     pop(mload(200))
+// }
diff --git a/test/libyul/yulOptimizerTests/memoryStoreRemover/complex8.yul b/test/libyul/yulOptimizerTests/memoryStoreRemover/complex8.yul
new file mode 100644
index 000000000..1c92f6656
--- /dev/null
+++ b/test/libyul/yulOptimizerTests/memoryStoreRemover/complex8.yul
@@ -0,0 +1,19 @@
+{
+    let x := 0
+    let y := 10
+    f(x, y)
+    function f(a, b) {
+        // cannot be removed, since a and b are considered as free variables
+        mstore(a, b)
+    }
+}
+// ----
+// step: memoryStoreRemover
+//
+// {
+//     let x := 0
+//     let y := 10
+//     f(x, y)
+//     function f(a, b)
+//     { mstore(a, b) }
+// }
diff --git a/test/libyul/yulOptimizerTests/memoryStoreRemover/complex9.yul b/test/libyul/yulOptimizerTests/memoryStoreRemover/complex9.yul
new file mode 100644
index 000000000..a03b75700
--- /dev/null
+++ b/test/libyul/yulOptimizerTests/memoryStoreRemover/complex9.yul
@@ -0,0 +1,16 @@
+{
+    let x := 0
+    let y := 32
+    // can be removed
+    mstore(x, y)
+    return(0, 0)
+}
+// ----
+// step: memoryStoreRemover
+//
+// {
+//     let x := 0
+//     let y := 32
+//     pop(y)
+//     return(0, 0)
+// }
diff --git a/test/libyul/yulOptimizerTests/memoryStoreRemover/eip1985.yul b/test/libyul/yulOptimizerTests/memoryStoreRemover/eip1985.yul
new file mode 100644
index 000000000..3d6463db0
--- /dev/null
+++ b/test/libyul/yulOptimizerTests/memoryStoreRemover/eip1985.yul
@@ -0,0 +1,19 @@
+{
+    // 2**128
+    let x := 340282366920938463463374607431768211456
+    // The optimization step will remove the following `mstore`.
+    // EIP 1985 limits `msize()` to `2**32` and the `mstore`
+    // beyond the region would result in out of gas.
+    // By removing `mstore`, we are converting a snippet
+    // that will be always OOG into one that would execute.
+    mstore(x, 100)
+    sstore(0, 10)
+}
+// ----
+// step: memoryStoreRemover
+//
+// {
+//     let x := 340282366920938463463374607431768211456
+//     pop(100)
+//     sstore(0, 10)
+// }
diff --git a/test/libyul/yulOptimizerTests/memoryStoreRemover/msize.yul b/test/libyul/yulOptimizerTests/memoryStoreRemover/msize.yul
new file mode 100644
index 000000000..4553e8788
--- /dev/null
+++ b/test/libyul/yulOptimizerTests/memoryStoreRemover/msize.yul
@@ -0,0 +1,15 @@
+// Test to see if the rule is applied in presence of msize
+{
+    pop(msize())
+    let x := 100
+    // cannot be removed because of the msize
+    mstore(x, 100)
+}
+// ----
+// step: memoryStoreRemover
+//
+// {
+//     pop(msize())
+//     let x := 100
+//     mstore(x, 100)
+// }
diff --git a/test/libyul/yulOptimizerTests/memoryStoreRemover/overflow.yul b/test/libyul/yulOptimizerTests/memoryStoreRemover/overflow.yul
new file mode 100644
index 000000000..f775046e7
--- /dev/null
+++ b/test/libyul/yulOptimizerTests/memoryStoreRemover/overflow.yul
@@ -0,0 +1,20 @@
+{
+    let x := 0
+    let y := 100
+    // Actually cannot be removed.
+    mstore(x, y)
+
+    // Even though this cannot happen in practice,
+    // we'll unfortunately have to deal with this situation.
+    // reads from bytes 2*256 - 1, 0, ..., 30
+    pop(mload(115792089237316195423570985008687907853269984665640564039457584007913129639935))
+}
+// ----
+// step: memoryStoreRemover
+//
+// {
+//     let x := 0
+//     let y := 100
+//     mstore(x, y)
+//     pop(mload(115792089237316195423570985008687907853269984665640564039457584007913129639935))
+// }
diff --git a/test/libyul/yulOptimizerTests/memoryStoreRemover/overflow_mstore.yul b/test/libyul/yulOptimizerTests/memoryStoreRemover/overflow_mstore.yul
new file mode 100644
index 000000000..42b67a377
--- /dev/null
+++ b/test/libyul/yulOptimizerTests/memoryStoreRemover/overflow_mstore.yul
@@ -0,0 +1,19 @@
+{
+    let x := 115792089237316195423570985008687907853269984665640564039457584007913129639935
+    let y := 1000
+    // Cannot be removed, since it writes to bytes
+    // 2**256 - 1, 0, 1, ..., 30
+    mstore(x, y)
+
+    // reads from [0, 32)
+    pop(mload(0))
+}
+// ----
+// step: memoryStoreRemover
+//
+// {
+//     let x := 115792089237316195423570985008687907853269984665640564039457584007913129639935
+//     let y := 1000
+//     mstore(x, y)
+//     pop(mload(0))
+// }
diff --git a/test/libyul/yulOptimizerTests/memoryStoreRemover/simple1.yul b/test/libyul/yulOptimizerTests/memoryStoreRemover/simple1.yul
new file mode 100644
index 000000000..e981a982d
--- /dev/null
+++ b/test/libyul/yulOptimizerTests/memoryStoreRemover/simple1.yul
@@ -0,0 +1,13 @@
+{
+    let x := 10
+    let y := 20
+    mstore(x, y)
+}
+// ----
+// step: memoryStoreRemover
+//
+// {
+//     let x := 10
+//     let y := 20
+//     pop(y)
+// }
diff --git a/test/libyul/yulOptimizerTests/memoryStoreRemover/simple10.yul b/test/libyul/yulOptimizerTests/memoryStoreRemover/simple10.yul
new file mode 100644
index 000000000..76bd86ad4
--- /dev/null
+++ b/test/libyul/yulOptimizerTests/memoryStoreRemover/simple10.yul
@@ -0,0 +1,29 @@
+{
+    let x := 0
+    // y is not a SSA Variable
+    let y := 20
+    if calldataload(10) {
+        y := 100
+    }
+    // The location is not read from.
+    // Even though the value is not an identifier, let alone an SSA variable.
+    mstore(x, calldataload(y))
+    mstore(x, y)
+
+    // does not read from memory
+    pop(extcodesize(0))
+    // does not read from [0, 32)
+    log0(100, 200)
+}
+// ----
+// step: memoryStoreRemover
+//
+// {
+//     let x := 0
+//     let y := 20
+//     if calldataload(10) { y := 100 }
+//     pop(calldataload(y))
+//     pop(y)
+//     pop(extcodesize(0))
+//     log0(100, 200)
+// }
diff --git a/test/libyul/yulOptimizerTests/memoryStoreRemover/simple2.yul b/test/libyul/yulOptimizerTests/memoryStoreRemover/simple2.yul
new file mode 100644
index 000000000..bd3badc64
--- /dev/null
+++ b/test/libyul/yulOptimizerTests/memoryStoreRemover/simple2.yul
@@ -0,0 +1,17 @@
+{
+    let x := 10
+    let y := 60
+    // can be removed
+    mstore(x, y)
+    // Does not read from [10, 42)
+    pop(mload(y))
+}
+// ----
+// step: memoryStoreRemover
+//
+// {
+//     let x := 10
+//     let y := 60
+//     pop(y)
+//     pop(mload(y))
+// }
diff --git a/test/libyul/yulOptimizerTests/memoryStoreRemover/simple3.yul b/test/libyul/yulOptimizerTests/memoryStoreRemover/simple3.yul
new file mode 100644
index 000000000..4a88e91bd
--- /dev/null
+++ b/test/libyul/yulOptimizerTests/memoryStoreRemover/simple3.yul
@@ -0,0 +1,17 @@
+{
+    let x := 10
+    let y := 20
+    // This should not be removed
+    mstore(x, y)
+    // reads from x
+    pop(mload(x))
+}
+// ----
+// step: memoryStoreRemover
+//
+// {
+//     let x := 10
+//     let y := 20
+//     mstore(x, y)
+//     pop(mload(x))
+// }
diff --git a/test/libyul/yulOptimizerTests/memoryStoreRemover/simple4.yul b/test/libyul/yulOptimizerTests/memoryStoreRemover/simple4.yul
new file mode 100644
index 000000000..552853c4e
--- /dev/null
+++ b/test/libyul/yulOptimizerTests/memoryStoreRemover/simple4.yul
@@ -0,0 +1,19 @@
+{
+    let x := 10
+    let y := 10
+    // should not be removed because of the if statement
+    mstore(x, y)
+    if calldataload(0) {
+       // reads inside control flow
+       pop(mload(x))
+    }
+}
+// ----
+// step: memoryStoreRemover
+//
+// {
+//     let x := 10
+//     let y := 10
+//     mstore(x, y)
+//     if calldataload(0) { pop(mload(x)) }
+// }
diff --git a/test/libyul/yulOptimizerTests/memoryStoreRemover/simple5.yul b/test/libyul/yulOptimizerTests/memoryStoreRemover/simple5.yul
new file mode 100644
index 000000000..c533eb8fe
--- /dev/null
+++ b/test/libyul/yulOptimizerTests/memoryStoreRemover/simple5.yul
@@ -0,0 +1,19 @@
+{
+    // x is not in SSA form
+    let x := 10
+    if calldataload(0) {
+       x := 25
+    }
+    let y := 20
+    // Should not be removed because x is not in SSA form
+    mstore(x, y)
+}
+// ----
+// step: memoryStoreRemover
+//
+// {
+//     let x := 10
+//     if calldataload(0) { x := 25 }
+//     let y := 20
+//     mstore(x, y)
+// }
diff --git a/test/libyul/yulOptimizerTests/memoryStoreRemover/simple6.yul b/test/libyul/yulOptimizerTests/memoryStoreRemover/simple6.yul
new file mode 100644
index 000000000..19ad7ebf8
--- /dev/null
+++ b/test/libyul/yulOptimizerTests/memoryStoreRemover/simple6.yul
@@ -0,0 +1,21 @@
+{
+    let x := 10
+    let y := 20
+    let z := 30
+
+    // even though `x` is assigned twice, both `mstores` can be removed.
+    mstore(x, y)
+    mstore(x, z)
+    pop(mload(100))
+}
+// ----
+// step: memoryStoreRemover
+//
+// {
+//     let x := 10
+//     let y := 20
+//     let z := 30
+//     pop(y)
+//     pop(z)
+//     pop(mload(100))
+// }
diff --git a/test/libyul/yulOptimizerTests/memoryStoreRemover/simple7.yul b/test/libyul/yulOptimizerTests/memoryStoreRemover/simple7.yul
new file mode 100644
index 000000000..873e9ee5c
--- /dev/null
+++ b/test/libyul/yulOptimizerTests/memoryStoreRemover/simple7.yul
@@ -0,0 +1,19 @@
+{
+
+    let x := 10
+    let y := 20
+    pop(mload(x))
+
+    // can't be removed even though nothing is read afterwards, because we'll check reads from the
+    // entire block.
+    mstore(x, y)
+}
+// ----
+// step: memoryStoreRemover
+//
+// {
+//     let x := 10
+//     let y := 20
+//     pop(mload(x))
+//     mstore(x, y)
+// }
diff --git a/test/libyul/yulOptimizerTests/memoryStoreRemover/simple8.yul b/test/libyul/yulOptimizerTests/memoryStoreRemover/simple8.yul
new file mode 100644
index 000000000..709ae548e
--- /dev/null
+++ b/test/libyul/yulOptimizerTests/memoryStoreRemover/simple8.yul
@@ -0,0 +1,21 @@
+{
+    f()
+    function f() {
+        let x := 10
+        let y := 20
+        // will never be read, so can be removed
+        mstore(x, y)
+    }
+}
+// ----
+// step: memoryStoreRemover
+//
+// {
+//     f()
+//     function f()
+//     {
+//         let x := 10
+//         let y := 20
+//         pop(y)
+//     }
+// }
diff --git a/test/libyul/yulOptimizerTests/memoryStoreRemover/simple9.yul b/test/libyul/yulOptimizerTests/memoryStoreRemover/simple9.yul
new file mode 100644
index 000000000..682062ff4
--- /dev/null
+++ b/test/libyul/yulOptimizerTests/memoryStoreRemover/simple9.yul
@@ -0,0 +1,24 @@
+{
+    f()
+    pop(mload(16))
+    function f() {
+        let x := 10
+        let y := 20
+
+        // cannot be removed
+        mstore(x, y)
+    }
+}
+// ----
+// step: memoryStoreRemover
+//
+// {
+//     f()
+//     pop(mload(16))
+//     function f()
+//     {
+//         let x := 10
+//         let y := 20
+//         mstore(x, y)
+//     }
+// }
diff --git a/test/libyul/yulOptimizerTests/memoryStoreRemover/smoke.yul b/test/libyul/yulOptimizerTests/memoryStoreRemover/smoke.yul
new file mode 100644
index 000000000..2209e744d
--- /dev/null
+++ b/test/libyul/yulOptimizerTests/memoryStoreRemover/smoke.yul
@@ -0,0 +1,5 @@
+{ }
+// ----
+// step: memoryStoreRemover
+//
+// { }