Eliminate identity casts (#29435)

Prevents the generation of instructions that cast the the same type
during code generation.

Author: IGI-111

crates/passes/src/code_generation/expression.rs

@@ -262,6 +262,11 @@ impl CodeGeneratingVisitor<'_> {
         let (operand, mut instructions) = self.visit_expression(&input.expression);
         let operand = operand.expect("Trying to cast an empty expression");
 
+        // if the source already has the target type, reuse its operand directly instead of emitting a no-op cast.
+        if self.state.type_table.get(&input.expression.id()).as_ref() == Some(&input.type_) {
+            return (operand, instructions);
+        }
+
         // Construct the destination register.
         let dest_reg = self.next_register();
 
@@ -1129,8 +1134,8 @@ impl CodeGeneratingVisitor<'_> {
         let new_reg = self.next_register();
         match typ {
             Type::Address => {
-                let ins = AleoStmt::Cast(register.clone(), new_reg.clone(), AleoType::Address);
-                ((AleoExpr::Reg(new_reg)), vec![ins])
+                let cast = AleoStmt::Cast(register.clone(), new_reg.clone(), AleoType::Address);
+                ((AleoExpr::Reg(new_reg)), vec![cast])
             }
             Type::Boolean => {
                 let ins = AleoStmt::Cast(register.clone(), new_reg.clone(), AleoType::Boolean);

tests/expectations/compiler/dyn_record/dyn_record_cast_as_field_access.out

@@ -8,5 +8,4 @@ function main:
     input r0 as Token.record;
     cast r0 into r1 as dynamic.record;
     get.record.dynamic r1.balance into r2 as u64;
-    cast r2 into r3 as u64;
-    output r3 as u64.private;
+    output r2 as u64.private;

tests/expectations/compiler/expression/cast.out

@@ -30,169 +30,158 @@ function main:
     cast r0 into r26 as scalar;
     cast r1 into r27 as field;
     cast r1 into r28 as group;
-    cast r1 into r29 as boolean;
-    cast r1 into r30 as i8;
-    cast r1 into r31 as i16;
-    cast r1 into r32 as i32;
-    cast r1 into r33 as i64;
-    cast r1 into r34 as i128;
-    cast r1 into r35 as u8;
-    cast r1 into r36 as u16;
-    cast r1 into r37 as u32;
-    cast r1 into r38 as u64;
-    cast r1 into r39 as u128;
-    cast r1 into r40 as scalar;
-    cast r2 into r41 as field;
-    cast r2 into r42 as group;
-    cast r2 into r43 as boolean;
-    cast r2 into r44 as i8;
-    cast r2 into r45 as i16;
-    cast r2 into r46 as i32;
-    cast r2 into r47 as i64;
-    cast r2 into r48 as i128;
-    cast r2 into r49 as u8;
-    cast r2 into r50 as u16;
-    cast r2 into r51 as u32;
-    cast r2 into r52 as u64;
-    cast r2 into r53 as u128;
-    cast r2 into r54 as scalar;
-    cast r3 into r55 as field;
-    cast r3 into r56 as group;
-    cast r3 into r57 as boolean;
-    cast r3 into r58 as i8;
-    cast r3 into r59 as i16;
-    cast r3 into r60 as i32;
-    cast r3 into r61 as i64;
-    cast r3 into r62 as i128;
-    cast r3 into r63 as u8;
-    cast r3 into r64 as u16;
-    cast r3 into r65 as u32;
-    cast r3 into r66 as u64;
-    cast r3 into r67 as u128;
-    cast r3 into r68 as scalar;
-    cast r4 into r69 as field;
-    cast r4 into r70 as group;
-    cast r4 into r71 as boolean;
-    cast r4 into r72 as i8;
-    cast r4 into r73 as i16;
-    cast r4 into r74 as i32;
-    cast r4 into r75 as i64;
-    cast r4 into r76 as i128;
-    cast r4 into r77 as u8;
-    cast r4 into r78 as u16;
-    cast r4 into r79 as u32;
-    cast r4 into r80 as u64;
-    cast r4 into r81 as u128;
-    cast r4 into r82 as scalar;
-    cast r5 into r83 as field;
-    cast r5 into r84 as group;
-    cast r5 into r85 as boolean;
-    cast r5 into r86 as i8;
-    cast r5 into r87 as i16;
-    cast r5 into r88 as i32;
-    cast r5 into r89 as i64;
-    cast r5 into r90 as i128;
-    cast r5 into r91 as u8;
-    cast r5 into r92 as u16;
-    cast r5 into r93 as u32;
-    cast r5 into r94 as u64;
-    cast r5 into r95 as u128;
-    cast r5 into r96 as scalar;
-    cast r6 into r97 as field;
-    cast r6 into r98 as group;
-    cast r6 into r99 as boolean;
-    cast r6 into r100 as i8;
-    cast r6 into r101 as i16;
-    cast r6 into r102 as i32;
-    cast r6 into r103 as i64;
-    cast r6 into r104 as i128;
-    cast r6 into r105 as u8;
-    cast r6 into r106 as u16;
-    cast r6 into r107 as u32;
-    cast r6 into r108 as u64;
-    cast r6 into r109 as u128;
-    cast r6 into r110 as scalar;
-    cast r7 into r111 as field;
-    cast r7 into r112 as group;
-    cast r7 into r113 as boolean;
-    cast r7 into r114 as i8;
-    cast r7 into r115 as i16;
-    cast r7 into r116 as i32;
-    cast r7 into r117 as i64;
-    cast r7 into r118 as i128;
-    cast r7 into r119 as u8;
-    cast r7 into r120 as u16;
-    cast r7 into r121 as u32;
-    cast r7 into r122 as u64;
-    cast r7 into r123 as u128;
-    cast r7 into r124 as scalar;
-    cast r8 into r125 as field;
-    cast r8 into r126 as group;
-    cast r8 into r127 as boolean;
-    cast r8 into r128 as i8;
-    cast r8 into r129 as i16;
-    cast r8 into r130 as i32;
-    cast r8 into r131 as i64;
-    cast r8 into r132 as i128;
-    cast r8 into r133 as u8;
-    cast r8 into r134 as u16;
-    cast r8 into r135 as u32;
-    cast r8 into r136 as u64;
-    cast r8 into r137 as u128;
-    cast r8 into r138 as scalar;
-    cast r9 into r139 as field;
-    cast r9 into r140 as group;
-    cast r9 into r141 as boolean;
-    cast r9 into r142 as i8;
-    cast r9 into r143 as i16;
-    cast r9 into r144 as i32;
-    cast r9 into r145 as i64;
-    cast r9 into r146 as i128;
-    cast r9 into r147 as u8;
-    cast r9 into r148 as u16;
-    cast r9 into r149 as u32;
-    cast r9 into r150 as u64;
-    cast r9 into r151 as u128;
-    cast r9 into r152 as scalar;
-    cast r10 into r153 as field;
-    cast r10 into r154 as group;
-    cast r10 into r155 as boolean;
-    cast r10 into r156 as i8;
-    cast r10 into r157 as i16;
-    cast r10 into r158 as i32;
-    cast r10 into r159 as i64;
-    cast r10 into r160 as i128;
-    cast r10 into r161 as u8;
-    cast r10 into r162 as u16;
-    cast r10 into r163 as u32;
-    cast r10 into r164 as u64;
-    cast r10 into r165 as u128;
-    cast r11 into r166 as field;
-    cast r11 into r167 as group;
-    cast r11 into r168 as boolean;
-    cast r11 into r169 as i8;
-    cast r11 into r170 as i16;
-    cast r11 into r171 as i32;
-    cast r11 into r172 as i64;
-    cast r11 into r173 as i128;
-    cast r11 into r174 as u8;
-    cast r11 into r175 as u16;
-    cast r11 into r176 as u32;
-    cast r11 into r177 as u64;
-    cast r11 into r178 as u128;
-    cast r11 into r179 as scalar;
-    cast r12 into r180 as field;
-    cast r12 into r181 as group;
-    cast r12 into r182 as boolean;
-    cast r12 into r183 as i8;
-    cast r12 into r184 as i16;
-    cast r12 into r185 as i32;
-    cast r12 into r186 as i64;
-    cast r12 into r187 as i128;
-    cast r12 into r188 as u8;
-    cast r12 into r189 as u16;
-    cast r12 into r190 as u32;
-    cast r12 into r191 as u64;
-    cast r12 into r192 as u128;
-    is.eq r166 r180 into r193;
-    output r193 as boolean.private;
+    cast r1 into r29 as i8;
+    cast r1 into r30 as i16;
+    cast r1 into r31 as i32;
+    cast r1 into r32 as i64;
+    cast r1 into r33 as i128;
+    cast r1 into r34 as u8;
+    cast r1 into r35 as u16;
+    cast r1 into r36 as u32;
+    cast r1 into r37 as u64;
+    cast r1 into r38 as u128;
+    cast r1 into r39 as scalar;
+    cast r2 into r40 as group;
+    cast r2 into r41 as boolean;
+    cast r2 into r42 as i8;
+    cast r2 into r43 as i16;
+    cast r2 into r44 as i32;
+    cast r2 into r45 as i64;
+    cast r2 into r46 as i128;
+    cast r2 into r47 as u8;
+    cast r2 into r48 as u16;
+    cast r2 into r49 as u32;
+    cast r2 into r50 as u64;
+    cast r2 into r51 as u128;
+    cast r2 into r52 as scalar;
+    cast r3 into r53 as field;
+    cast r3 into r54 as group;
+    cast r3 into r55 as boolean;
+    cast r3 into r56 as i16;
+    cast r3 into r57 as i32;
+    cast r3 into r58 as i64;
+    cast r3 into r59 as i128;
+    cast r3 into r60 as u8;
+    cast r3 into r61 as u16;
+    cast r3 into r62 as u32;
+    cast r3 into r63 as u64;
+    cast r3 into r64 as u128;
+    cast r3 into r65 as scalar;
+    cast r4 into r66 as field;
+    cast r4 into r67 as group;
+    cast r4 into r68 as boolean;
+    cast r4 into r69 as i8;
+    cast r4 into r70 as i32;
+    cast r4 into r71 as i64;
+    cast r4 into r72 as i128;
+    cast r4 into r73 as u8;
+    cast r4 into r74 as u16;
+    cast r4 into r75 as u32;
+    cast r4 into r76 as u64;
+    cast r4 into r77 as u128;
+    cast r4 into r78 as scalar;
+    cast r5 into r79 as field;
+    cast r5 into r80 as group;
+    cast r5 into r81 as boolean;
+    cast r5 into r82 as i8;
+    cast r5 into r83 as i16;
+    cast r5 into r84 as i32;
+    cast r5 into r85 as i128;
+    cast r5 into r86 as u8;
+    cast r5 into r87 as u16;
+    cast r5 into r88 as u32;
+    cast r5 into r89 as u64;
+    cast r5 into r90 as u128;
+    cast r5 into r91 as scalar;
+    cast r6 into r92 as field;
+    cast r6 into r93 as group;
+    cast r6 into r94 as boolean;
+    cast r6 into r95 as i8;
+    cast r6 into r96 as i16;
+    cast r6 into r97 as i32;
+    cast r6 into r98 as i64;
+    cast r6 into r99 as u8;
+    cast r6 into r100 as u16;
+    cast r6 into r101 as u32;
+    cast r6 into r102 as u64;
+    cast r6 into r103 as u128;
+    cast r6 into r104 as scalar;
+    cast r7 into r105 as field;
+    cast r7 into r106 as group;
+    cast r7 into r107 as boolean;
+    cast r7 into r108 as i8;
+    cast r7 into r109 as i16;
+    cast r7 into r110 as i32;
+    cast r7 into r111 as i64;
+    cast r7 into r112 as i128;
+    cast r7 into r113 as u16;
+    cast r7 into r114 as u32;
+    cast r7 into r115 as u64;
+    cast r7 into r116 as u128;
+    cast r7 into r117 as scalar;
+    cast r8 into r118 as field;
+    cast r8 into r119 as group;
+    cast r8 into r120 as boolean;
+    cast r8 into r121 as i8;
+    cast r8 into r122 as i16;
+    cast r8 into r123 as i32;
+    cast r8 into r124 as i64;
+    cast r8 into r125 as i128;
+    cast r8 into r126 as u8;
+    cast r8 into r127 as u32;
+    cast r8 into r128 as u64;
+    cast r8 into r129 as u128;
+    cast r8 into r130 as scalar;
+    cast r9 into r131 as field;
+    cast r9 into r132 as group;
+    cast r9 into r133 as boolean;
+    cast r9 into r134 as i8;
+    cast r9 into r135 as i16;
+    cast r9 into r136 as i32;
+    cast r9 into r137 as i64;
+    cast r9 into r138 as i128;
+    cast r9 into r139 as u8;
+    cast r9 into r140 as u16;
+    cast r9 into r141 as u64;
+    cast r9 into r142 as u128;
+    cast r9 into r143 as scalar;
+    cast r10 into r144 as field;
+    cast r10 into r145 as group;
+    cast r10 into r146 as boolean;
+    cast r10 into r147 as i8;
+    cast r10 into r148 as i16;
+    cast r10 into r149 as i32;
+    cast r10 into r150 as i64;
+    cast r10 into r151 as i128;
+    cast r10 into r152 as u8;
+    cast r10 into r153 as u16;
+    cast r10 into r154 as u32;
+    cast r10 into r155 as u128;
+    cast r11 into r156 as field;
+    cast r11 into r157 as group;
+    cast r11 into r158 as boolean;
+    cast r11 into r159 as i8;
+    cast r11 into r160 as i16;
+    cast r11 into r161 as i32;
+    cast r11 into r162 as i64;
+    cast r11 into r163 as i128;
+    cast r11 into r164 as u8;
+    cast r11 into r165 as u16;
+    cast r11 into r166 as u32;
+    cast r11 into r167 as u64;
+    cast r11 into r168 as scalar;
+    cast r12 into r169 as field;
+    cast r12 into r170 as group;
+    cast r12 into r171 as boolean;
+    cast r12 into r172 as i8;
+    cast r12 into r173 as i16;
+    cast r12 into r174 as i32;
+    cast r12 into r175 as i64;
+    cast r12 into r176 as i128;
+    cast r12 into r177 as u8;
+    cast r12 into r178 as u16;
+    cast r12 into r179 as u32;
+    cast r12 into r180 as u64;
+    cast r12 into r181 as u128;
+    is.eq r156 r169 into r182;
+    output r182 as boolean.private;