bjoernager/rust
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Stop generating allocas+memcmp for simple array equality

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This commit is contained in:
Scott McMurray 2021-05-30 10:25:41 -07:00
parent d05eafae2f
commit 2456495a26
12 changed files with 238 additions and 4 deletions
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26
compiler/rustc_codegen_llvm/src/intrinsic.rs
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@ -296,6 +296,32 @@ impl IntrinsicCallMethods<'tcx> for Builder<'a, 'll, 'tcx> {
}
}
sym::raw_eq => {
let tp_ty = substs.type_at(0);
let (size, align) = self.size_and_align_of(tp_ty);
let a = args[0].immediate();
let b = args[1].immediate();
if size.bytes() == 0 {
self.const_bool(true)
} else if size > self.data_layout().pointer_size * 4 {
let i8p_ty = self.type_i8p();
let a_ptr = self.bitcast(a, i8p_ty);
let b_ptr = self.bitcast(b, i8p_ty);
let n = self.const_usize(size.bytes());
let llfn = self.get_intrinsic("memcmp");
let cmp = self.call(llfn, &[a_ptr, b_ptr, n], None);
self.icmp(IntPredicate::IntEQ, cmp, self.const_i32(0))
} else {
let integer_ty = self.type_ix(size.bits());
let ptr_ty = self.type_ptr_to(integer_ty);
let a_ptr = self.bitcast(a, ptr_ty);
let a_val = self.load(a_ptr, align);
let b_ptr = self.bitcast(b, ptr_ty);
let b_val = self.load(b_ptr, align);
self.icmp(IntPredicate::IntEQ, a_val, b_val)
}
}
_ if name_str.starts_with("simd_") => {
match generic_simd_intrinsic(self, name, callee_ty, args, ret_ty, llret_ty, span) {
Ok(llval) => llval,