/* 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.
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.