Update model solution.

- Stop calculating operands for & operators.
- Evaluate the lhs of compound operators only once.
- Add `side-effect.c` example.

examples/opt/hello_main.ir

@@ -2,7 +2,7 @@
 fun i32 @main () {
 init:
   bid: b0
-  allocations:
+  allocations: 
 
 
 block b0:

examples/opt/pointer.ir

@@ -19,19 +19,15 @@ init:
 block b0:
   %b0:i0:unit = store 1:i32 %l0:i32*
   %b0:i1:i32* = call @foo:[ret:i32* params:(i32*)]*(%l0:i32*)
-  %b0:i2:i32* = call @foo:[ret:i32* params:(i32*)]*(%l0:i32*)
-  %b0:i3:i32* = call @foo:[ret:i32* params:(i32*)]*(%l0:i32*)
-  %b0:i4:i32* = call @foo:[ret:i32* params:(i32*)]*(%l0:i32*)
-  %b0:i5:i32 = load %b0:i4:i32*
-  %b0:i6:i32 = add %b0:i5:i32 1:i32
-  %b0:i7:unit = store %b0:i6:i32 %b0:i2:i32*
-  %b0:i8:i32* = call @foo:[ret:i32* params:(i32*)]*(%l0:i32*)
-  %b0:i9:i32* = call @foo:[ret:i32* params:(i32*)]*(%l0:i32*)
-  %b0:i10:i32 = load %b0:i9:i32*
-  %b0:i11:i32 = add %b0:i10:i32 1:i32
-  %b0:i12:unit = store %b0:i11:i32 %b0:i8:i32*
-  %b0:i13:i32 = load %l0:i32*
-  %b0:i14:u1 = cmp eq %b0:i13:i32 3:i32
-  %b0:i15:i32 = typecast %b0:i14:u1 to i32
-  ret %b0:i15:i32
+  %b0:i2:i32 = load %b0:i1:i32*
+  %b0:i3:i32 = add %b0:i2:i32 1:i32
+  %b0:i4:unit = store %b0:i3:i32 %b0:i1:i32*
+  %b0:i5:i32* = call @foo:[ret:i32* params:(i32*)]*(%l0:i32*)
+  %b0:i6:i32 = load %b0:i5:i32*
+  %b0:i7:i32 = add %b0:i6:i32 1:i32
+  %b0:i8:unit = store %b0:i7:i32 %b0:i5:i32*
+  %b0:i9:i32 = load %l0:i32*
+  %b0:i10:u1 = cmp eq %b0:i9:i32 3:i32
+  %b0:i11:i32 = typecast %b0:i10:u1 to i32
+  ret %b0:i11:i32
 }

examples/opt/side_effect.ir

@@ -0,0 +1,29 @@
+var i32 @g = 0
+
+fun i32* @foo () {
+init:
+  bid: b0
+  allocations: 
+
+
+block b0:
+  %b0:i0:i32 = load @g:i32*
+  %b0:i1:i32 = add %b0:i0:i32 10:i32
+  %b0:i2:unit = store %b0:i1:i32 @g:i32*
+  ret @g:i32*
+}
+
+fun i32 @main () {
+init:
+  bid: b0
+  allocations: 
+
+
+block b0:
+  %b0:i0:i32* = call @foo:[ret:i32* params:()]*()
+  %b0:i1:i32 = load %b0:i0:i32*
+  %b0:i2:i32 = add %b0:i1:i32 1:i32
+  %b0:i3:unit = store %b0:i2:i32 %b0:i0:i32*
+  %b0:i4:i32 = load @g:i32*
+  ret %b0:i4:i32
+}