Make DataFlowAnalyzer aware of storage / memory slot after sload / mload.

test/libyul/yulOptimizerTests/loadResolver/double_mload.yul

@@ -0,0 +1,13 @@
+{
+    let x := calldataload(0)
+    let a := mload(x)
+    let b := mload(x)
+    sstore(a, b)
+}
+// ----
+// step: loadResolver
+//
+// {
+//     let a := mload(calldataload(0))
+//     sstore(a, a)
+// }

test/libyul/yulOptimizerTests/loadResolver/double_mload_with_other_reassignment.yul

@@ -0,0 +1,16 @@
+{
+    let x := calldataload(0)
+    let a := mload(x)
+    x := 7
+    let b := mload(x)
+    sstore(a, b)
+}
+// ----
+// step: loadResolver
+//
+// {
+//     let x := calldataload(0)
+//     let a := mload(x)
+//     x := 7
+//     sstore(a, mload(x))
+// }

test/libyul/yulOptimizerTests/loadResolver/double_mload_with_reassignment.yul

@@ -0,0 +1,16 @@
+{
+    let x := calldataload(0)
+    let a := mload(x)
+    a := 7
+    let b := mload(x)
+    sstore(a, b)
+}
+// ----
+// step: loadResolver
+//
+// {
+//     let x := calldataload(0)
+//     let a := mload(x)
+//     a := 7
+//     sstore(a, mload(x))
+// }

test/libyul/yulOptimizerTests/loadResolver/merge_mload_with_known_distance.yul

@@ -0,0 +1,19 @@
+{
+    let x := mload(calldataload(0))
+    if calldataload(1) {
+        mstore(add(calldataload(0), 0x20), 1)
+    }
+    let t := mload(add(calldataload(0), 0x20))
+    let q := mload(calldataload(0))
+    sstore(t, q)
+}
+// ----
+// step: loadResolver
+//
+// {
+//     let _2 := calldataload(0)
+//     let x := mload(_2)
+//     let _3 := 1
+//     if calldataload(_3) { mstore(add(_2, 0x20), _3) }
+//     sstore(mload(add(_2, 0x20)), x)
+// }

test/libyul/yulOptimizerTests/loadResolver/merge_mload_with_rewrite.yul

@@ -0,0 +1,22 @@
+{
+    let b := mload(2)
+    if calldataload(1) {
+        mstore(2, 7)
+        // Re-writing the old value, should allow to eliminate the load below.
+        mstore(2, b)
+    }
+    sstore(0, mload(2))
+}
+// ----
+// step: loadResolver
+//
+// {
+//     let _1 := 2
+//     let b := mload(_1)
+//     if calldataload(1)
+//     {
+//         mstore(_1, 7)
+//         mstore(_1, b)
+//     }
+//     sstore(0, b)
+// }

test/libyul/yulOptimizerTests/loadResolver/merge_mload_without_rewrite.yul

@@ -0,0 +1,19 @@
+{
+    let b := mload(2)
+    sstore(0, b)
+    if calldataload(1) {
+        mstore(2, 7)
+    }
+    sstore(0, mload(2))
+}
+// ----
+// step: loadResolver
+//
+// {
+//     let _1 := 2
+//     let b := mload(_1)
+//     let _2 := 0
+//     sstore(_2, b)
+//     if calldataload(1) { mstore(_1, 7) }
+//     sstore(_2, mload(_1))
+// }

test/libyul/yulOptimizerTests/loadResolver/mload_self.yul

@@ -0,0 +1,15 @@
+{
+    let x := calldataload(0)
+    x := mload(x)
+    let y := mload(x)
+    sstore(0, y)
+}
+// ----
+// step: loadResolver
+//
+// {
+//     let _1 := 0
+//     let x := calldataload(_1)
+//     x := mload(x)
+//     sstore(_1, mload(x))
+// }

test/libyul/yulOptimizerTests/loadResolver/multi_sload_loop.yul

@@ -0,0 +1,30 @@
+{
+    let x := calldataload(0)
+    let len := sload(x)
+    let sum
+    for { let i := 0} lt(i, sload(x)) { i := add(i, 1) } {
+        let p := add(x, add(i, 1))
+        if gt(p, sload(x)) { revert(0, 0) }
+        sum := add(sum, sload(p))
+    }
+    mstore(0, sum)
+    return(0, 0x20)
+}
+// ----
+// step: loadResolver
+//
+// {
+//     let _1 := 0
+//     let x := calldataload(_1)
+//     let len := sload(x)
+//     let sum
+//     let i := _1
+//     for { } lt(i, len) { i := add(i, 1) }
+//     {
+//         let p := add(add(x, i), 1)
+//         if gt(p, len) { revert(_1, _1) }
+//         sum := add(sum, sload(p))
+//     }
+//     mstore(_1, sum)
+//     return(_1, 0x20)
+// }