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* split the optimizer
This commit is contained in:
Jonas Maebe
parent
2bfc4fa33d
commit
892964eaf2
1961
compiler/aopt386.pas
1961
compiler/aopt386.pas
File diff suppressed because it is too large
Load Diff
397
compiler/csopt386.pas
Normal file
397
compiler/csopt386.pas
Normal file
@ -0,0 +1,397 @@
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{
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$Id$
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Copyright (c) 1997-98 by Jonas Maebe
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This unit contains the common subexpression elimination procedure.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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****************************************************************************
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}
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Unit CSOpt386;
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Interface
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Uses aasm;
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{Procedure CSOpt386(First, Last: Pai);}
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Procedure CSE(AsmL: PAasmOutput; First, Last: Pai);
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Implementation
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Uses CObjects, globals, systems, verbose, hcodegen
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{$ifdef i386}
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,i386, cgi386, DAOpt386
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{$endif i386}
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;
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Function CheckSequence(p: Pai; Reg: TRegister; Var Found: Longint): Boolean;
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{checks whether the current instruction sequence (starting with p) and the
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one between StartMod and EndMod of Reg are the same. If so, the number of
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instructions that match is stored in Found and true is returned, otherwise
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Found holds the number of instructions between StartMod and EndMod and false
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is returned}
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Var hp2, hp3, EndMod: Pai;
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TmpResult: Boolean;
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RegsNotYetChecked: Set Of TRegister;
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Counter: Byte;
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Function NoChangedRegInRef(oldp, newp: Pai): Boolean;
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Var TmpP: Pai;
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{checks if the first operator of newp is a reference and in that case checks
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whether that reference includes regs that have been changed since oldp. This
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to avoid wrong optimizations like
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movl 8(%epb), %eax movl 8(%epb), %eax
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movl 12(%epb), %edx movl 12(%epb), %edx
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movl (%eax,%edx,1), %edi movl (%eax,%edx,1), %edi
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pushl %edi being converted to pushl %edi
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movl 8(%epb), %eax movl 16(%ebp), %edx
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movl 16(%epb), %edx pushl %edi
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movl (%eax,%edx,1), %edi
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pushl %edi
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because first is checked whether %eax isn't changed (it isn't) and
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consequently all instructions containg %eax are removed}
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Begin
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TmpResult := True;
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If (Pai(oldp)^.typ = ait_instruction) Then {oldp and newp are the same instruction}
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Case Pai386(oldp)^.op1t Of
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Top_Reg:
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If (Reg32(TRegister(Pai386(oldp)^.op1)) in RegsNotYetChecked) Then
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Begin
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RegsNotYetChecked := RegsNotYetChecked - [Reg32(TRegister(Pai386(oldp)^.op1))];
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If Assigned(newp^.previous)
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Then
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Begin
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TmpP := Pai(newp^.previous);
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While Assigned (TmpP^.previous) And
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PPaiProp(TmpP^.fileinfo.Line)^.CanBeRemoved Do
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TmpP := Pai(TmpP^.previous);
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TmpResult := Assigned(TmpP) And
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RegsSameContent(oldp, TmpP, Reg32(TRegister(Pai386(oldp)^.op1)))
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End
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Else TmpResult := False;
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End;
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Top_Ref:
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With TReference(Pai386(oldp)^.op1^) Do
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Begin
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If (Base in RegsNotYetChecked) And
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(Base <> R_NO) Then
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Begin
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RegsNotYetChecked := RegsNotYetChecked - [Base];
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If Assigned(newp^.previous)
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Then
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Begin
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TmpP := Pai(newp^.previous);
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While Assigned (TmpP^.previous) And
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PPaiProp(TmpP^.fileinfo.Line)^.CanBeRemoved Do
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TmpP := Pai(TmpP^.previous);
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TmpResult := Assigned(TmpP) And
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RegsSameContent(oldp, TmpP, Base)
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End
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Else TmpResult := False;
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End;
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If TmpResult And
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(Index <> R_NO) And
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(Index in RegsNotYetChecked) Then
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Begin
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RegsNotYetChecked := RegsNotYetChecked - [Index];
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If Assigned(newp^.previous)
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Then
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Begin
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TmpP := Pai(newp^.previous);
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While Assigned (TmpP^.previous) And
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PPaiProp(TmpP^.fileinfo.Line)^.CanBeRemoved Do
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TmpP := Pai(TmpP^.previous);
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TmpResult := Assigned(TmpP) And
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RegsSameContent(oldp, TmpP, Index)
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End
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Else TmpResult := False;
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End;
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End;
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End;
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NoChangedRegInRef := TmpResult;
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End;
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Begin {CheckSequence}
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Reg := Reg32(Reg);
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Found := 0;
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hp2 := PPaiProp(Pai(p^.previous)^.fileinfo.line)^.Regs[Reg].StartMod;
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hp3 := p;
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EndMod := PPaiProp(Pai(p^.previous)^.fileinfo.line)^.Regs[Reg].StartMod;
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RegsNotYetChecked := [R_EAX..R_EDI];
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For Counter := 2 to PPaiProp(Pai(p^.previous)^.fileinfo.line)^.Regs[Reg].NrOfMods Do
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EndMod := Pai(EndMod^.Next);
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While (Found <> PPaiProp(Pai(p^.previous)^.fileinfo.line)^.Regs[Reg].NrOfMods) And
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InstructionsEqual(hp2, hp3) And
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NoChangedRegInRef(EndMod, hp3) Do
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Begin
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hp2 := Pai(hp2^.next);
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hp3 := Pai(hp3^.next);
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Inc(Found)
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End;
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If (Found <> PPaiProp(Pai(p^.previous)^.fileinfo.line)^.Regs[Reg].NrOfMods)
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Then
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Begin
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If ((Found+1) = PPaiProp(Pai(p^.previous)^.fileinfo.line)^.Regs[Reg].NrOfMods) And
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Assigned(hp2) And
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(Pai(hp2)^.typ = ait_instruction) And
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(Pai386(hp2)^._operator In [A_MOV, A_MOVZX]) And
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(Pai386(hp2)^.op1t = top_ref) And
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(Pai386(hp2)^.op2t = top_reg) And
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Assigned(hp3) And
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(Pai(hp3)^.typ = ait_instruction) And
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(Pai386(hp3)^._operator In [A_MOV, A_MOVZX]) And
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(Pai386(hp3)^.op1t = top_ref) And
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(Pai386(hp3)^.op2t = top_reg) And
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(Pai386(hp2)^._operator <> Pai386(hp3)^._operator) And
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RefsEqual(TReference(Pai386(hp2)^.op1^),TReference(Pai386(hp3)^.op1^)) And
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NoChangedRegInRef(EndMod, hp3)
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Then
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If (Pai386(hp2)^._operator = A_MOV)
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Then
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Begin
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If (Pai386(hp2)^.Size = S_B) And
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(Reg8toReg32(TRegister(Pai386(hp2)^.op2)) =
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TRegister(Pai386(hp3)^.op2))
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Then
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Begin
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Pai386(hp2)^._operator := A_MOVZX;
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Pai386(hp2)^.op2 := Pai386(hp3)^.op2;
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Pai386(hp2)^.Size := S_BL;
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Inc(Found);
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CheckSequence := True;
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End
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Else
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Begin
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CheckSequence := False;
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If (Found > 0) Then
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Found := PPaiProp(Pai(p)^.fileinfo.line)^.Regs[Reg].NrOfMods
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End
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End
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Else
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Begin
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If (Pai386(hp3)^.Size = S_B) And
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(Reg8toReg32(TRegister(Pai386(hp3)^.op2)) =
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TRegister(Pai386(hp2)^.op2))
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Then
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Begin
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CheckSequence := True;
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Inc(Found)
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End
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Else
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Begin
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CheckSequence := False;
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If (Found > 0) Then
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Found := PPaiProp(Pai(p)^.fileinfo.line)^.Regs[Reg].NrOfMods
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End
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End
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Else
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Begin
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CheckSequence := False;
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If (found > 0) then
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{this is correct because we only need to turn off the CanBeRemoved flag
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when an instruction has already been processed by CheckSequence
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(otherwise CanBeRemoved can't be true, or can't have to be turned off).
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If it has already been processed by checkSequence and flagged to be
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removed, it means that it has been checked against a previous sequence
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and that it was equal (otherwise CheckSequence would have returned false
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and the instruction wouldn't have been removed). If this "If found > 0"
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check is left out, incorrect optimizations are performed.}
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Found := PPaiProp(Pai(p)^.fileinfo.line)^.Regs[Reg].NrOfMods
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End
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End
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Else CheckSequence := True;
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End; {CheckSequence}
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Procedure DoCSE(First, Last: Pai);
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{marks the instructions that can be removed by RemoveInstructs. They're not
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removed immediately because sometimes an instruction needs to be checked in
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two different sequences}
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Var Cnt, Cnt2: Longint;
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p, hp1, hp2: Pai;
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Begin
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p := First;
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While (p <> Pai(Last^.Next)) Do
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Begin
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Case p^.typ Of
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ait_label, ait_labeled_instruction:;
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ait_instruction:
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Begin
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Case Pai386(p)^._operator Of
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A_CLD: If Assigned(p^.previous) And
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(PPaiProp(Pai(p^.previous)^.fileinfo.line)^.DirFlag = F_NotSet) Then
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PPaiProp(Pai(p)^.fileinfo.line)^.CanBeRemoved := True;
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A_MOV, A_MOVZX, A_MOVSX:
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Begin
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Case Pai386(p)^.op1t Of
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{ Top_Reg:
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Case Pai386(p)^.op2t Of
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Top_Reg:;
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Top_Ref:;
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End;}
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Top_Ref:
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Begin {destination is always a register in this case}
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With PPaiProp(p^.fileinfo.line)^.Regs[Reg32(Tregister(Pai386(p)^.op2))] Do
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Begin
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If Assigned(p^.previous) And
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(PPaiProp(Pai(p^.previous)^.fileinfo.line)^.
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Regs[Reg32(TRegister(Pai386(p)^.op2))].typ = con_ref) Then
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{so we don't try to check a sequence when the register only contains a constant}
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If CheckSequence(p, TRegister(Pai386(p)^.op2), Cnt) And
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(Cnt > 0)
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Then
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Begin
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hp1 := nil;
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{although it's perfectly ok to remove an instruction which doesn't contain
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the register that we've just checked (CheckSequence takes care of that),
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the sequence containing this other register should also be completely
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checked and removed, otherwise we may get situations like this:
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movl 12(%ebp), %edx movl 12(%ebp), %edx
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movl 16(%ebp), %eax movl 16(%ebp), %eax
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movl 8(%edx), %edx movl 8(%edx), %edx
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movl (%eax), eax movl (%eax), eax
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cmpl %eax, %edx cmpl %eax, %edx
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jnz l123 getting converted to jnz l123
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movl 12(%ebp), %edx movl 4(%eax), eax
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movl 16(%ebp), %eax
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movl 8(%edx), %edx
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movl 4(%eax), eax}
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hp2 := p;
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For Cnt2 := 1 to Cnt Do
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Begin
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{ Note to Jonas :
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ait_stab_function_name is only at the begin of one function
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ait_stabn is only inserted in ag so you should not see any
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ait_stabs are only in head and tail of procs
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so you should no have problems with those neither !! (PM)
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Tell me if I am wrong
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If Not(Pai(p)^.typ In [ait_stabs, ait_stabn, ait_stab_function_name]) Then }
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Begin
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If (hp1 = nil) And
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Not(RegInInstruction(Tregister(Pai386(hp2)^.op2), p))
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Then hp1 := p;
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PPaiProp(p^.fileinfo.line)^.CanBeRemoved := True;
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End;
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p := Pai(p^.next);
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End;
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If hp1 <> nil Then p := hp1;
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Continue;
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End
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Else
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If (Cnt > 0) And
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(PPaiProp(p^.fileinfo.line)^.CanBeRemoved) Then
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Begin
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hp2 := p;
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For Cnt2 := 1 to Cnt Do
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Begin
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If RegInInstruction(Tregister(Pai386(hp2)^.op2), p)
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Then PPaiProp(p^.fileinfo.line)^.CanBeRemoved := False;
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p := Pai(p^.Next)
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End;
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Continue;
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End;
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End;
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End;
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Top_Const:
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Begin
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Case Pai386(p)^.op2t Of
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Top_Reg:
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Begin
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If Assigned(p^.previous) Then
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With PPaiProp(Pai(p^.previous)^.fileinfo.line)^.Regs[Reg32(TRegister(Pai386(p)^.op2))] Do
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If (Typ = Con_Const) And
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(StartMod = Pai386(p)^.op1) Then
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PPaiProp(p^.fileinfo.line)^.CanBeRemoved := True;
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End;
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Top_Ref:;
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End;
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End;
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End;
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End;
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A_STD: If Assigned(p^.previous) And
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(PPaiProp(Pai(p^.previous)^.fileinfo.line)^.DirFlag = F_Set) Then
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PPaiProp(Pai(p)^.fileinfo.line)^.CanBeRemoved := True;
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A_XOR:
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Begin
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If (Pai386(p)^.op1t = top_reg) And
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(Pai386(p)^.op2t = top_reg) And
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(Pai386(p)^.op1 = Pai386(p)^.op2) And
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Assigned(p^.previous) And
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(PPaiProp(Pai(p^.previous)^.fileinfo.line)^.Regs[Reg32(Tregister(Pai386(p)^.op1))].typ = con_const) And
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(PPaiProp(Pai(p^.previous)^.fileinfo.line)^.Regs[Reg32(Tregister(Pai386(p)^.op1))].StartMod = Pointer(0))
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Then PPaiProp(p^.fileinfo.line)^.CanBeRemoved := True
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End
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End
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End;
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End;
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p := Pai(p^.next);
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End;
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End;
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Procedure RemoveInstructs(AsmL: PAasmOutput; First, Last: Pai);
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{Removes the marked instructions and disposes the PPaiProps of the other
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instructions, restoring theirline number}
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Var p, hp1: Pai;
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TmpLine, InstrCnt: Longint;
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Begin
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p := First;
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InstrCnt := 1;
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While (p <> Pai(Last^.Next)) Do
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If PPaiProp(p^.fileinfo.line)^.CanBeRemoved
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Then
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Begin
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If (InstrCnt > NrOfPaiFast) Then
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Dispose(PPaiProp(p^.fileinfo.line));
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hp1 := Pai(p^.Next);
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AsmL^.Remove(p);
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Dispose(p, Done);
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p := hp1;
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Inc(InstrCnt)
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End
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Else
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Begin
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If (InstrCnt > NrOfPaiFast)
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Then
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Begin
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TmpLine := PPaiProp(p^.fileinfo.line)^.linesave;
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Dispose(PPaiProp(p^.fileinfo.line));
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p^.fileinfo.line := TmpLine;
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End
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Else p^.fileinfo.line := PPaiProp(p^.fileinfo.line)^.linesave;
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p := Pai(p^.Next);
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Inc(InstrCnt)
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End;
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If (NrOfPaiFast > 0) Then
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{$IfDef TP}
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Freemem(PaiPropBlock, NrOfPaiFast*(((SizeOf(TPaiProp)+1)div 2)*2))
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{$Else}
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FreeMem(PaiPropBlock, NrOfPaiFast*(((SizeOf(TPaiProp)+3)div 4)*4))
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{$EndIf TP}
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End;
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Procedure CSE(AsmL: PAasmOutput; First, Last: Pai);
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Begin
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DoCSE(First, Last);
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RemoveInstructs(AsmL, First, Last);
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End;
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End.
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{
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$log$
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}
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1208
compiler/daopt386.pas
Normal file
1208
compiler/daopt386.pas
Normal file
File diff suppressed because it is too large
Load Diff
1376
compiler/popt386.pas
Normal file
1376
compiler/popt386.pas
Normal file
File diff suppressed because it is too large
Load Diff
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