diff options
Diffstat (limited to 'compiler/rustc_codegen_ssa/src')
| -rw-r--r-- | compiler/rustc_codegen_ssa/src/mir/rvalue.rs | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/compiler/rustc_codegen_ssa/src/mir/rvalue.rs b/compiler/rustc_codegen_ssa/src/mir/rvalue.rs index e05d03d150f..bd11d47500a 100644 --- a/compiler/rustc_codegen_ssa/src/mir/rvalue.rs +++ b/compiler/rustc_codegen_ssa/src/mir/rvalue.rs @@ -290,7 +290,13 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> { use abi::Primitive::*; imm = bx.from_immediate(imm); + + // When scalars are passed by value, there's no metadata recording their + // valid ranges. For example, `char`s are passed as just `i32`, with no + // way for LLVM to know that they're 0x10FFFF at most. Thus we assume + // the range of the input value too, not just the output range. self.assume_scalar_range(bx, imm, from_scalar, from_backend_ty); + imm = match (from_scalar.primitive(), to_scalar.primitive()) { (Int(..) | F32 | F64, Int(..) | F32 | F64) => bx.bitcast(imm, to_backend_ty), (Pointer(..), Pointer(..)) => bx.pointercast(imm, to_backend_ty), @@ -318,6 +324,9 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> { backend_ty: Bx::Type, ) { if matches!(self.cx.sess().opts.optimize, OptLevel::No | OptLevel::Less) + // For now, the critical niches are all over `Int`eger values. + // Should floating-point values or pointers ever get more complex + // niches, then this code will probably want to handle them too. || !matches!(scalar.primitive(), abi::Primitive::Int(..)) || scalar.is_always_valid(self.cx) { |