Replace as casts with type-conversion functions.

https://github.com/rust-lang-nursery/rust-clippy/wiki#cast_lossless

lib/cretonne/src/isa/constraints.rs

@@ -105,7 +105,7 @@ impl BranchRange {
     ///
     /// This method does not detect if the range is larger than 2 GB.
     pub fn contains(self, branch: CodeOffset, dest: CodeOffset) -> bool {
-        let d = dest.wrapping_sub(branch + self.origin as CodeOffset) as i32;
+        let d = dest.wrapping_sub(branch + CodeOffset::from(self.origin)) as i32;
         let s = 32 - self.bits;
         d == d << s >> s
     }

lib/cretonne/src/isa/encoding.rs

@@ -124,7 +124,7 @@ impl EncInfo {
     pub fn bytes(&self, enc: Encoding) -> CodeOffset {
         self.sizing
             .get(enc.recipe())
-            .map(|s| s.bytes as CodeOffset)
+            .map(|s| CodeOffset::from(s.bytes))
             .unwrap_or(0)
     }
 

lib/cretonne/src/isa/intel/abi.rs

@@ -28,7 +28,7 @@ struct Args {
 impl Args {
     fn new(bits: u16, gpr: &'static [RU], fpr_limit: usize) -> Args {
         Args {
-            pointer_bytes: bits as u32 / 8,
+            pointer_bytes: u32::from(bits) / 8,
             pointer_bits: bits,
             pointer_type: ir::Type::int(bits).unwrap(),
             gpr,

lib/cretonne/src/isa/registers.rs

@@ -174,7 +174,7 @@ impl RegClassData {
 
     /// Get a specific register unit in this class.
     pub fn unit(&self, offset: usize) -> RegUnit {
-        let uoffset = offset * self.width as usize;
+        let uoffset = offset * usize::from(self.width);
         self.first + uoffset as RegUnit
     }
 
@@ -209,7 +209,7 @@ impl EntityRef for RegClassIndex {
     }
 
     fn index(self) -> usize {
-        self.0 as usize
+        usize::from(self.0)
     }
 }
 

lib/cretonne/src/isa/riscv/abi.rs

@@ -26,7 +26,7 @@ impl Args {
     fn new(bits: u16, enable_e: bool) -> Args {
         Args {
             pointer_bits: bits,
-            pointer_bytes: bits as u32 / 8,
+            pointer_bytes: u32::from(bits) / 8,
             pointer_type: Type::int(bits).unwrap(),
             regs: 0,
             reg_limit: if enable_e { 6 } else { 8 },