diff options
Diffstat (limited to 'compiler')
| -rw-r--r-- | compiler/rustc_codegen_ssa/src/mir/rvalue.rs | 28 |
1 files changed, 21 insertions, 7 deletions
diff --git a/compiler/rustc_codegen_ssa/src/mir/rvalue.rs b/compiler/rustc_codegen_ssa/src/mir/rvalue.rs index 3b62148abb7..31793641d75 100644 --- a/compiler/rustc_codegen_ssa/src/mir/rvalue.rs +++ b/compiler/rustc_codegen_ssa/src/mir/rvalue.rs @@ -93,23 +93,37 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> { return; } - if let OperandValue::Immediate(v) = cg_elem.val { + let try_init_all_same = |bx: &mut Bx, v| { let start = dest.val.llval; let size = bx.const_usize(dest.layout.size.bytes()); - // Use llvm.memset.p0i8.* to initialize all zero arrays - if bx.cx().const_to_opt_u128(v, false) == Some(0) { - let fill = bx.cx().const_u8(0); - bx.memset(start, fill, size, dest.val.align, MemFlags::empty()); - return; + // Use llvm.memset.p0i8.* to initialize all same byte arrays + if let Some(int) = bx.cx().const_to_opt_u128(v, false) { + let bytes = &int.to_le_bytes()[..cg_elem.layout.size.bytes_usize()]; + let first = bytes[0]; + if bytes[1..].iter().all(|&b| b == first) { + let fill = bx.cx().const_u8(first); + bx.memset(start, fill, size, dest.val.align, MemFlags::empty()); + return true; + } } // Use llvm.memset.p0i8.* to initialize byte arrays let v = bx.from_immediate(v); if bx.cx().val_ty(v) == bx.cx().type_i8() { bx.memset(start, v, size, dest.val.align, MemFlags::empty()); - return; + return true; + } + false + }; + + match cg_elem.val { + OperandValue::Immediate(v) => { + if try_init_all_same(bx, v) { + return; + } } + _ => (), } let count = self |