[Optimize Instructions] Refactor squared rules (#4840)

+ Move these rules to separate function;
+ Refactor them to use matches;
+ Add comments;
+ Handle rotational shifts as well;
+ Handle overflows for `<<`, `>>`, `>>>` shifts;
+ Add mixed rotate rules:
```rust
   rotl(rotr(x, C1), C2)   =>   rotr(x, C1 - C2)
   rotr(rotl(x, C1), C2)   =>   rotl(x, C1 - C2)
```

1 files changed, 8 insertions, 4 deletions

diff --git a/src/ir/abstract.h b/src/ir/abstract.h
index feac9b50d..0cfeeea77 100644
--- a/src/ir/abstract.h
+++ b/src/ir/abstract.h
@@ -59,13 +59,17 @@ enum Op {
   GeU
 };
 
-inline bool hasAnyShift(BinaryOp op) {
-  return op == ShlInt32 || op == ShrSInt32 || op == ShrUInt32 ||
-         op == RotLInt32 || op == RotRInt32 || op == ShlInt64 ||
-         op == ShrSInt64 || op == ShrUInt64 || op == RotLInt64 ||
+inline bool hasAnyRotateShift(BinaryOp op) {
+  return op == RotLInt32 || op == RotRInt32 || op == RotLInt64 ||
          op == RotRInt64;
 }
 
+inline bool hasAnyShift(BinaryOp op) {
+  return hasAnyRotateShift(op) || op == ShlInt32 || op == ShrSInt32 ||
+         op == ShrUInt32 || op == ShlInt64 || op == ShrSInt64 ||
+         op == ShrUInt64;
+}
+
 inline bool hasAnyReinterpret(UnaryOp op) {
   return op == ReinterpretInt32 || op == ReinterpretInt64 ||
          op == ReinterpretFloat32 || op == ReinterpretFloat64;