but not if it is an overlapping register. */
#ifdef OVERLAPPING_REGNO_P
#define FIXED_REGNO_P(N) \
- (((N) == FRAME_POINTER_REGNUM || fixed_regs[N]) \
+ (((N) == FRAME_POINTER_REGNUM \
+ || ((N) < FIRST_PSEUDO_REGISTER && fixed_regs[N])) \
&& ! OVERLAPPING_REGNO_P ((N)))
#else
#define FIXED_REGNO_P(N) \
- ((N) == FRAME_POINTER_REGNUM || fixed_regs[N])
+ ((N) == FRAME_POINTER_REGNUM \
+ || ((N) < FIRST_PSEUDO_REGISTER && fixed_regs[N]))
#endif
/* Compute cost of X, as stored in the `cost' field of a table_elt. Fixed
Otherwise, return X, possibly with one or more operands
modified by recursive calls to this function.
- If X is a register whose contents are known, we do NOT
- return those contents. This is because an instruction that
- uses a register is usually faster than one that uses a constant.
+ If X is a register whose contents are known, we may or may not
+ return those contents. An instruction that uses a register is usually
+ faster than one that uses a constant. But on machines with few hard
+ regs, using a register instead of a constant increases register life,
+ hurting register allocation.
INSN is the insn that we may be modifying. If it is 0, make a copy
of X before modifying it. */