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calls.c (expand_call): When copying unaligned values into a register...

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* calls.c (expand_call): When copying unaligned values into a register,
	zero out the register first rather than emitting a clobber.

From-SVN: r13898
This commit is contained in:
Doug Evans 1997-04-13 23:30:18 +00:00
parent 58a32c5c03
commit a22ad97227
1 changed files with 8 additions and 2 deletions
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10
gcc/calls.c
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@ -1782,9 +1782,15 @@ expand_call (exp, target, ignore)
/* Clobber REG and move each partword into it. Ensure we don't
go past the end of the structure. Note that the loop below
works because we've already verified that padding
and endianness are compatible. */
and endianness are compatible.
emit_insn (gen_rtx (CLOBBER, VOIDmode, reg));
We use to emit a clobber here but that doesn't let later
passes optimize the instructions we emit. By storing 0 into
the register later passes know the first AND to zero out the
bitfield being set in the register is unnecessary. The store
of 0 will be deleted as will at least the first AND. */
emit_move_insn (reg, const0_rtx);
for (bitpos = 0;
bitpos < BITS_PER_WORD && bytes > 0;