Update REG_EQUIV comment for assign_parms change

From-SVN: r13735
This commit is contained in:
Ian Lance Taylor 1997-03-18 20:00:38 +00:00
parent 38b610ed8e
commit f75487ff65
1 changed files with 9 additions and 7 deletions

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@ -1,5 +1,5 @@
/* Register Transfer Language (RTL) definitions for GNU C-Compiler
Copyright (C) 1987, 91-95, 1996 Free Software Foundation, Inc.
Copyright (C) 1987, 91-96, 1997 Free Software Foundation, Inc.
This file is part of GNU CC.
@ -257,13 +257,15 @@ typedef struct rtvec_def{
not needed past this insn). If REG is set in this insn, the REG_DEAD
note may, but need not, be omitted.
REG_INC means that the REG is autoincremented or autodecremented.
REG_EQUIV describes the insn as a whole; it says that the
insn sets a register to a constant value or to be equivalent to
a memory address. If the
register is spilled to the stack then the constant value
should be substituted for it. The contents of the REG_EQUIV
REG_EQUIV describes the insn as a whole; it says that the insn
sets a register to a constant value or to be equivalent to a memory
address. If the register is spilled to the stack then the constant
value should be substituted for it. The contents of the REG_EQUIV
is the constant value or memory address, which may be different
from the source of the SET although it has the same value.
from the source of the SET although it has the same value. A
REG_EQUIV note may also appear on an insn which copies a register
parameter to a pseudo-register, if there is a memory address which
could be used to hold that pseudo-register throughout the function.
REG_EQUAL is like REG_EQUIV except that the destination
is only momentarily equal to the specified rtx. Therefore, it
cannot be used for substitution; but it can be used for cse.