Changes in directory llvm/lib/Target/X86:
X86.td updated: 1.21 -> 1.22
X86CodeEmitter.cpp updated: 1.86 -> 1.87
X86InstrInfo.h updated: 1.48 -> 1.49
X86InstrInfo.td updated: 1.226 -> 1.227
---
Log message:
- Use xor to clear integer registers (set R, 0).
- Added a new format for instructions where the source register is implied
and it is same as the destination register. Used for pseudo instructions
that clear the destination register.
---
Diffs of the changes: (+39 -17)
X86.td | 8 ++++----
X86CodeEmitter.cpp | 7 ++++++-
X86InstrInfo.h | 18 +++++++++++-------
X86InstrInfo.td | 23 ++++++++++++++++++-----
4 files changed, 39 insertions(+), 17 deletions(-)
Index: llvm/lib/Target/X86/X86.td
diff -u llvm/lib/Target/X86/X86.td:1.21 llvm/lib/Target/X86/X86.td:1.22
--- llvm/lib/Target/X86/X86.td:1.21 Tue Jan 31 13:43:35 2006
+++ llvm/lib/Target/X86/X86.td Wed Feb 1 00:13:50 2006
@@ -110,11 +110,11 @@
"FPFormBits",
"Opcode"];
let TSFlagsShifts = [0,
- 5,
6,
- 10,
- 12,
- 16];
+ 7,
+ 11,
+ 13,
+ 17];
}
// The X86 target supports two different syntaxes for emitting machine code.
Index: llvm/lib/Target/X86/X86CodeEmitter.cpp
diff -u llvm/lib/Target/X86/X86CodeEmitter.cpp:1.86
llvm/lib/Target/X86/X86CodeEmitter.cpp:1.87
--- llvm/lib/Target/X86/X86CodeEmitter.cpp:1.86 Sat Jan 28 12:19:37 2006
+++ llvm/lib/Target/X86/X86CodeEmitter.cpp Wed Feb 1 00:13:50 2006
@@ -473,7 +473,6 @@
case X86II::MRMSrcReg:
MCE.emitByte(BaseOpcode);
-
emitRegModRMByte(MI.getOperand(1).getReg(),
getX86RegNum(MI.getOperand(0).getReg()));
if (MI.getNumOperands() == 3)
@@ -518,5 +517,11 @@
assert(0 && "Unknown operand!");
}
break;
+
+ case X86II::MRMInitReg:
+ MCE.emitByte(BaseOpcode);
+ emitRegModRMByte(MI.getOperand(0).getReg(),
+ getX86RegNum(MI.getOperand(0).getReg()));
+ break;
}
}
Index: llvm/lib/Target/X86/X86InstrInfo.h
diff -u llvm/lib/Target/X86/X86InstrInfo.h:1.48
llvm/lib/Target/X86/X86InstrInfo.h:1.49
--- llvm/lib/Target/X86/X86InstrInfo.h:1.48 Wed Jul 27 00:53:44 2005
+++ llvm/lib/Target/X86/X86InstrInfo.h Wed Feb 1 00:13:50 2006
@@ -75,7 +75,11 @@
MRM0m = 24, MRM1m = 25, MRM2m = 26, MRM3m = 27, // Format /0 /1 /2 /3
MRM4m = 28, MRM5m = 29, MRM6m = 30, MRM7m = 31, // Format /4 /5 /6 /7
- FormMask = 31,
+ // MRMInitReg - This form is used for instructions whose source and
+ // destinations are the same register.
+ MRMInitReg = 32,
+
+ FormMask = 63,
//===------------------------------------------------------------------===//
// Actual flags...
@@ -83,14 +87,14 @@
// OpSize - Set if this instruction requires an operand size prefix (0x66),
// which most often indicates that the instruction operates on 16 bit data
// instead of 32 bit data.
- OpSize = 1 << 5,
+ OpSize = 1 << 6,
// Op0Mask - There are several prefix bytes that are used to form two byte
// opcodes. These are currently 0x0F, 0xF3, and 0xD8-0xDF. This mask is
// used to obtain the setting of this field. If no bits in this field is
// set, there is no prefix byte for obtaining a multibyte opcode.
//
- Op0Shift = 6,
+ Op0Shift = 7,
Op0Mask = 0xF << Op0Shift,
// TB - TwoByte - Set if this instruction has a two byte opcode, which
@@ -115,7 +119,7 @@
//===------------------------------------------------------------------===//
// This two-bit field describes the size of an immediate operand. Zero is
// unused so that we can tell if we forgot to set a value.
- ImmShift = 10,
+ ImmShift = 11,
ImmMask = 7 << ImmShift,
Imm8 = 1 << ImmShift,
Imm16 = 2 << ImmShift,
@@ -125,7 +129,7 @@
// FP Instruction Classification... Zero is non-fp instruction.
// FPTypeMask - Mask for all of the FP types...
- FPTypeShift = 12,
+ FPTypeShift = 13,
FPTypeMask = 7 << FPTypeShift,
// NotFP - The default, set for instructions that do not use FP registers.
@@ -158,9 +162,9 @@
SpecialFP = 7 << FPTypeShift,
// Bit 15 is unused.
- OpcodeShift = 16,
+ OpcodeShift = 17,
OpcodeMask = 0xFF << OpcodeShift,
- // Bits 24 -> 31 are unused
+ // Bits 25 -> 31 are unused
};
}
Index: llvm/lib/Target/X86/X86InstrInfo.td
diff -u llvm/lib/Target/X86/X86InstrInfo.td:1.226
llvm/lib/Target/X86/X86InstrInfo.td:1.227
--- llvm/lib/Target/X86/X86InstrInfo.td:1.226 Tue Jan 31 16:28:30 2006
+++ llvm/lib/Target/X86/X86InstrInfo.td Wed Feb 1 00:13:50 2006
@@ -180,8 +180,8 @@
// Format specifies the encoding used by the instruction. This is part of the
// ad-hoc solution used to emit machine instruction encodings by our machine
// code emitter.
-class Format<bits<5> val> {
- bits<5> Value = val;
+class Format<bits<6> val> {
+ bits<6> Value = val;
}
def Pseudo : Format<0>; def RawFrm : Format<1>;
@@ -194,6 +194,7 @@
def MRM0m : Format<24>; def MRM1m : Format<25>; def MRM2m : Format<26>;
def MRM3m : Format<27>; def MRM4m : Format<28>; def MRM5m : Format<29>;
def MRM6m : Format<30>; def MRM7m : Format<31>;
+def MRMInitReg : Format<32>;
//===----------------------------------------------------------------------===//
// X86 Instruction Predicate Definitions.
@@ -238,7 +239,7 @@
bits<8> Opcode = opcod;
Format Form = f;
- bits<5> FormBits = Form.Value;
+ bits<6> FormBits = Form.Value;
ImmType ImmT = i;
bits<2> ImmTypeBits = ImmT.Value;
@@ -708,6 +709,18 @@
"mov{l} {$src, $dst|$dst, $src}",
[(store R32:$src, addr:$dst)]>;
+// Pseudo-instructions that map movr0 to xor.
+// FIXME: remove when we can teach regalloc that xor reg, reg is ok.
+def MOV8r0 : I<0x30, MRMInitReg, (ops R8 :$dst),
+ "xor{b} $dst, $dst",
+ [(set R8:$dst, 0)]>;
+def MOV16r0 : I<0x31, MRMInitReg, (ops R16:$dst),
+ "xor{w} $dst, $dst",
+ [(set R16:$dst, 0)]>, OpSize;
+def MOV32r0 : I<0x31, MRMInitReg, (ops R32:$dst),
+ "xor{l} $dst, $dst",
+ [(set R32:$dst, 0)]>;
+
//===----------------------------------------------------------------------===//
// Fixed-Register Multiplication and Division Instructions...
//
@@ -2478,10 +2491,10 @@
// Pseudo-instructions that map fld0 to xorps/xorpd for sse.
// FIXME: remove when we can teach regalloc that xor reg, reg is ok.
-def FLD0SS : I<0x57, MRMSrcReg, (ops FR32:$dst),
+def FLD0SS : I<0x57, MRMInitReg, (ops FR32:$dst),
"xorps $dst, $dst", [(set FR32:$dst, fp32imm0)]>,
Requires<[HasSSE1]>, TB;
-def FLD0SD : I<0x57, MRMSrcReg, (ops FR64:$dst),
+def FLD0SD : I<0x57, MRMInitReg, (ops FR64:$dst),
"xorpd $dst, $dst", [(set FR64:$dst, fp64imm0)]>,
Requires<[HasSSE2]>, TB, OpSize;
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