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+ better precision in determining the registers, read by mul/imul/div/idiv in

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i386's TCpuAsmOptimizer.RegReadByInstruction:
  * mul doesn't read edx (unless included in operand)
  * 8-bit mul and imul don't read ah (unless included in operand)
  * 8-bit div and idiv don't read edx (unless included in operand)

git-svn-id: trunk@35958 -
This commit is contained in:
nickysn 2017-04-26 16:17:31 +00:00
parent 916c09af55
commit 0f010430cc
1 changed files with 21 additions and 5 deletions
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26
compiler/i386/aoptcpu.pas
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@ -160,17 +160,33 @@ unit aoptcpu;
A_IMUL:
case p.ops of
1:
regReadByInstruction :=
(reg = NR_EAX) or RegInOp(reg,p.oper[0]^);
regReadByInstruction := RegInOp(reg,p.oper[0]^) or
(
((getregtype(reg)=R_INTREGISTER) and (getsupreg(reg)=RS_EAX)) and
((getsubreg(reg)<>R_SUBH) or (p.opsize<>S_B))
);
2,3:
regReadByInstruction :=
reginop(reg,p.oper[0]^) or
reginop(reg,p.oper[1]^);
end;
A_IDIV,A_DIV,A_MUL:
A_MUL:
begin
regReadByInstruction :=
RegInOp(reg,p.oper[0]^) or ((getregtype(reg)=R_INTREGISTER) and (getsupreg(reg) in [RS_EAX,RS_EDX]));
regReadByInstruction := RegInOp(reg,p.oper[0]^) or
(
((getregtype(reg)=R_INTREGISTER) and (getsupreg(reg)=RS_EAX)) and
((getsubreg(reg)<>R_SUBH) or (p.opsize<>S_B))
);
end;
A_IDIV,A_DIV:
begin
regReadByInstruction := RegInOp(reg,p.oper[0]^) or
(
(getregtype(reg)=R_INTREGISTER) and
(
(getsupreg(reg)=RS_EAX) or ((getsupreg(reg)=RS_EDX) and (p.opsize<>S_B))
)
);
end;
else
begin