llvm-6502/lib/Target/ARM/ARMSubtarget.h
Dan Gohman 707e018423 Drop ISD::MEMSET, ISD::MEMMOVE, and ISD::MEMCPY, which are not Legal
on any current target and aren't optimized in DAGCombiner. Instead
of using intermediate nodes, expand the operations, choosing between
simple loads/stores, target-specific code, and library calls,
immediately.

Previously, the code to emit optimized code for these operations
was only used at initial SelectionDAG construction time; now it is
used at all times. This fixes some cases where rep;movs was being
used for small copies where simple loads/stores would be better.

This also cleans up code that checks for alignments less than 4;
let the targets make that decision instead of doing it in
target-independent code. This allows x86 to use rep;movs in
low-alignment cases.

Also, this fixes a bug that resulted in the use of rep;stos for
memsets of 0 with non-constant memory size when the alignment was
at least 4. It's better to use the library in this case, which
can be significantly faster when the size is large.

This also preserves more SourceValue information when memory
intrinsics are lowered into simple loads/stores.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@49572 91177308-0d34-0410-b5e6-96231b3b80d8
2008-04-12 04:36:06 +00:00

102 lines
3.3 KiB
C++

//=====---- ARMSubtarget.h - Define Subtarget for the ARM -----*- C++ -*--====//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file declares the ARM specific subclass of TargetSubtarget.
//
//===----------------------------------------------------------------------===//
#ifndef ARMSUBTARGET_H
#define ARMSUBTARGET_H
#include "llvm/Target/TargetSubtarget.h"
#include <string>
namespace llvm {
class Module;
class ARMSubtarget : public TargetSubtarget {
protected:
enum ARMArchEnum {
V4T, V5T, V5TE, V6
};
/// ARMArchVersion - ARM architecture vecrsion: V4T (base), V5T, V5TE,
/// and V6.
ARMArchEnum ARMArchVersion;
/// HasVFP2 - True if the processor supports Vector Floating Point (VFP) V2
/// instructions.
bool HasVFP2;
/// IsThumb - True if we are in thumb mode, false if in ARM mode.
bool IsThumb;
/// UseThumbBacktraces - True if we use thumb style backtraces.
bool UseThumbBacktraces;
/// IsR9Reserved - True if R9 is a not available as general purpose register.
bool IsR9Reserved;
/// stackAlignment - The minimum alignment known to hold of the stack frame on
/// entry to the function and which must be maintained by every function.
unsigned stackAlignment;
public:
enum {
isELF, isDarwin
} TargetType;
enum {
ARM_ABI_APCS,
ARM_ABI_AAPCS // ARM EABI
} TargetABI;
/// This constructor initializes the data members to match that
/// of the specified module.
///
ARMSubtarget(const Module &M, const std::string &FS, bool thumb);
/// getMaxInlineSizeThreshold - Returns the maximum memset / memcpy size
/// that still makes it profitable to inline the call.
unsigned getMaxInlineSizeThreshold() const {
// FIXME: For now, we don't lower memcpy's to loads / stores for Thumb.
// Change this once Thumb ldmia / stmia support is added.
return isThumb() ? 0 : 64;
}
/// ParseSubtargetFeatures - Parses features string setting specified
/// subtarget options. Definition of function is auto generated by tblgen.
void ParseSubtargetFeatures(const std::string &FS, const std::string &CPU);
bool hasV4TOps() const { return ARMArchVersion >= V4T; }
bool hasV5TOps() const { return ARMArchVersion >= V5T; }
bool hasV5TEOps() const { return ARMArchVersion >= V5TE; }
bool hasV6Ops() const { return ARMArchVersion >= V6; }
bool hasVFP2() const { return HasVFP2; }
bool isTargetDarwin() const { return TargetType == isDarwin; }
bool isTargetELF() const { return TargetType == isELF; }
bool isAPCS_ABI() const { return TargetABI == ARM_ABI_APCS; }
bool isAAPCS_ABI() const { return TargetABI == ARM_ABI_AAPCS; }
bool isThumb() const { return IsThumb; }
bool useThumbBacktraces() const { return UseThumbBacktraces; }
bool isR9Reserved() const { return IsR9Reserved; }
/// getStackAlignment - Returns the minimum alignment known to hold of the
/// stack frame on entry to the function and which must be maintained by every
/// function for this subtarget.
unsigned getStackAlignment() const { return stackAlignment; }
};
} // End llvm namespace
#endif // ARMSUBTARGET_H