Sometimes an developer would like to have more control over cmov vs branch. We have unpredictable metadata in LLVM IR, but currently it is ignored by X86 backend. Propagate this metadata and avoid cmov->branch conversion in X86CmovConversion for cmov with this metadata.
Example:
```
int MaxIndex(int n, int *a) {
int t = 0;
for (int i = 1; i < n; i++) {
// cmov is converted to branch by X86CmovConversion
if (a[i] > a[t]) t = i;
}
return t;
}
int MaxIndex2(int n, int *a) {
int t = 0;
for (int i = 1; i < n; i++) {
// cmov is preserved
if (__builtin_unpredictable(a[i] > a[t])) t = i;
}
return t;
}
```
Reviewed By: nikic
Differential Revision: https://reviews.llvm.org/D118118
254 lines
5.8 KiB
C++
254 lines
5.8 KiB
C++
//===- MILexer.h - Lexer for machine instructions ---------------*- C++ -*-===//
|
|
//
|
|
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
|
|
// See https://llvm.org/LICENSE.txt for license information.
|
|
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
//
|
|
// This file declares the function that lexes the machine instruction source
|
|
// string.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#ifndef LLVM_LIB_CODEGEN_MIRPARSER_MILEXER_H
|
|
#define LLVM_LIB_CODEGEN_MIRPARSER_MILEXER_H
|
|
|
|
#include "llvm/ADT/APSInt.h"
|
|
#include "llvm/ADT/StringRef.h"
|
|
#include <string>
|
|
|
|
namespace llvm {
|
|
|
|
class Twine;
|
|
|
|
/// A token produced by the machine instruction lexer.
|
|
struct MIToken {
|
|
enum TokenKind {
|
|
// Markers
|
|
Eof,
|
|
Error,
|
|
Newline,
|
|
|
|
// Tokens with no info.
|
|
comma,
|
|
equal,
|
|
underscore,
|
|
colon,
|
|
coloncolon,
|
|
dot,
|
|
exclaim,
|
|
lparen,
|
|
rparen,
|
|
lbrace,
|
|
rbrace,
|
|
plus,
|
|
minus,
|
|
less,
|
|
greater,
|
|
|
|
// Keywords
|
|
kw_implicit,
|
|
kw_implicit_define,
|
|
kw_def,
|
|
kw_dead,
|
|
kw_dereferenceable,
|
|
kw_killed,
|
|
kw_undef,
|
|
kw_internal,
|
|
kw_early_clobber,
|
|
kw_debug_use,
|
|
kw_renamable,
|
|
kw_tied_def,
|
|
kw_frame_setup,
|
|
kw_frame_destroy,
|
|
kw_nnan,
|
|
kw_ninf,
|
|
kw_nsz,
|
|
kw_arcp,
|
|
kw_contract,
|
|
kw_afn,
|
|
kw_reassoc,
|
|
kw_nuw,
|
|
kw_nsw,
|
|
kw_exact,
|
|
kw_nofpexcept,
|
|
kw_unpredictable,
|
|
kw_debug_location,
|
|
kw_debug_instr_number,
|
|
kw_dbg_instr_ref,
|
|
kw_cfi_same_value,
|
|
kw_cfi_offset,
|
|
kw_cfi_rel_offset,
|
|
kw_cfi_def_cfa_register,
|
|
kw_cfi_def_cfa_offset,
|
|
kw_cfi_adjust_cfa_offset,
|
|
kw_cfi_escape,
|
|
kw_cfi_def_cfa,
|
|
kw_cfi_llvm_def_aspace_cfa,
|
|
kw_cfi_register,
|
|
kw_cfi_remember_state,
|
|
kw_cfi_restore,
|
|
kw_cfi_restore_state,
|
|
kw_cfi_undefined,
|
|
kw_cfi_window_save,
|
|
kw_cfi_aarch64_negate_ra_sign_state,
|
|
kw_blockaddress,
|
|
kw_intrinsic,
|
|
kw_target_index,
|
|
kw_half,
|
|
kw_float,
|
|
kw_double,
|
|
kw_x86_fp80,
|
|
kw_fp128,
|
|
kw_ppc_fp128,
|
|
kw_target_flags,
|
|
kw_volatile,
|
|
kw_non_temporal,
|
|
kw_invariant,
|
|
kw_align,
|
|
kw_basealign,
|
|
kw_addrspace,
|
|
kw_stack,
|
|
kw_got,
|
|
kw_jump_table,
|
|
kw_constant_pool,
|
|
kw_call_entry,
|
|
kw_custom,
|
|
kw_liveout,
|
|
kw_landing_pad,
|
|
kw_inlineasm_br_indirect_target,
|
|
kw_ehfunclet_entry,
|
|
kw_liveins,
|
|
kw_successors,
|
|
kw_floatpred,
|
|
kw_intpred,
|
|
kw_shufflemask,
|
|
kw_pre_instr_symbol,
|
|
kw_post_instr_symbol,
|
|
kw_heap_alloc_marker,
|
|
kw_pcsections,
|
|
kw_cfi_type,
|
|
kw_bbsections,
|
|
kw_bb_id,
|
|
kw_unknown_size,
|
|
kw_unknown_address,
|
|
kw_ir_block_address_taken,
|
|
kw_machine_block_address_taken,
|
|
|
|
// Metadata types.
|
|
kw_distinct,
|
|
|
|
// Named metadata keywords
|
|
md_tbaa,
|
|
md_alias_scope,
|
|
md_noalias,
|
|
md_range,
|
|
md_diexpr,
|
|
md_dilocation,
|
|
|
|
// Identifier tokens
|
|
Identifier,
|
|
NamedRegister,
|
|
NamedVirtualRegister,
|
|
MachineBasicBlockLabel,
|
|
MachineBasicBlock,
|
|
StackObject,
|
|
FixedStackObject,
|
|
NamedGlobalValue,
|
|
GlobalValue,
|
|
ExternalSymbol,
|
|
MCSymbol,
|
|
|
|
// Other tokens
|
|
IntegerLiteral,
|
|
FloatingPointLiteral,
|
|
HexLiteral,
|
|
VectorLiteral,
|
|
VirtualRegister,
|
|
ConstantPoolItem,
|
|
JumpTableIndex,
|
|
NamedIRBlock,
|
|
IRBlock,
|
|
NamedIRValue,
|
|
IRValue,
|
|
QuotedIRValue, // `<constant value>`
|
|
SubRegisterIndex,
|
|
StringConstant
|
|
};
|
|
|
|
private:
|
|
TokenKind Kind = Error;
|
|
StringRef Range;
|
|
StringRef StringValue;
|
|
std::string StringValueStorage;
|
|
APSInt IntVal;
|
|
|
|
public:
|
|
MIToken() = default;
|
|
|
|
MIToken &reset(TokenKind Kind, StringRef Range);
|
|
|
|
MIToken &setStringValue(StringRef StrVal);
|
|
MIToken &setOwnedStringValue(std::string StrVal);
|
|
MIToken &setIntegerValue(APSInt IntVal);
|
|
|
|
TokenKind kind() const { return Kind; }
|
|
|
|
bool isError() const { return Kind == Error; }
|
|
|
|
bool isNewlineOrEOF() const { return Kind == Newline || Kind == Eof; }
|
|
|
|
bool isErrorOrEOF() const { return Kind == Error || Kind == Eof; }
|
|
|
|
bool isRegister() const {
|
|
return Kind == NamedRegister || Kind == underscore ||
|
|
Kind == NamedVirtualRegister || Kind == VirtualRegister;
|
|
}
|
|
|
|
bool isRegisterFlag() const {
|
|
return Kind == kw_implicit || Kind == kw_implicit_define ||
|
|
Kind == kw_def || Kind == kw_dead || Kind == kw_killed ||
|
|
Kind == kw_undef || Kind == kw_internal ||
|
|
Kind == kw_early_clobber || Kind == kw_debug_use ||
|
|
Kind == kw_renamable;
|
|
}
|
|
|
|
bool isMemoryOperandFlag() const {
|
|
return Kind == kw_volatile || Kind == kw_non_temporal ||
|
|
Kind == kw_dereferenceable || Kind == kw_invariant ||
|
|
Kind == StringConstant;
|
|
}
|
|
|
|
bool is(TokenKind K) const { return Kind == K; }
|
|
|
|
bool isNot(TokenKind K) const { return Kind != K; }
|
|
|
|
StringRef::iterator location() const { return Range.begin(); }
|
|
|
|
StringRef range() const { return Range; }
|
|
|
|
/// Return the token's string value.
|
|
StringRef stringValue() const { return StringValue; }
|
|
|
|
const APSInt &integerValue() const { return IntVal; }
|
|
|
|
bool hasIntegerValue() const {
|
|
return Kind == IntegerLiteral || Kind == MachineBasicBlock ||
|
|
Kind == MachineBasicBlockLabel || Kind == StackObject ||
|
|
Kind == FixedStackObject || Kind == GlobalValue ||
|
|
Kind == VirtualRegister || Kind == ConstantPoolItem ||
|
|
Kind == JumpTableIndex || Kind == IRBlock || Kind == IRValue;
|
|
}
|
|
};
|
|
|
|
/// Consume a single machine instruction token in the given source and return
|
|
/// the remaining source string.
|
|
StringRef lexMIToken(
|
|
StringRef Source, MIToken &Token,
|
|
function_ref<void(StringRef::iterator, const Twine &)> ErrorCallback);
|
|
|
|
} // end namespace llvm
|
|
|
|
#endif // LLVM_LIB_CODEGEN_MIRPARSER_MILEXER_H
|