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(instantiate_virtual_regs_1, case USE, case CLOBBER): Properly handle
case of shared MEM whose replacement is not valid.

From-SVN: r13509
This commit is contained in:
Richard Kenner 1997-01-19 08:57:20 -05:00
parent 02a27e82af
commit 4fd796bbb5
1 changed files with 21 additions and 4 deletions
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25
gcc/function.c
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@ -2942,7 +2942,7 @@ instantiate_virtual_regs_1 (loc, object, extra_insns)
case MEM:
/* Most cases of MEM that convert to valid addresses have already been
handled by our scan of regno_reg_rtx. The only special handling we
handled by our scan of decls. The only special handling we
need here is to make a copy of the rtx to ensure it isn't being
shared if we have to change it to a pseudo.
@ -3000,7 +3000,9 @@ instantiate_virtual_regs_1 (loc, object, extra_insns)
??? Also note that this can still lose if OBJECT is an insn that
has less restrictions on an address that some other insn.
In that case, we will modify the shared address. This case
doesn't seem very likely, though. */
doesn't seem very likely, though. One case where this could
happen is in the case of a USE or CLOBBER reference, but we
take care of that below. */
if (instantiate_virtual_regs_1 (&XEXP (x, 0),
object ? object : x, 0))
@ -3013,8 +3015,6 @@ instantiate_virtual_regs_1 (loc, object, extra_insns)
}
/* Fall through to generic unary operation case. */
case USE:
case CLOBBER:
case SUBREG:
case STRICT_LOW_PART:
case NEG: case NOT:
@ -3031,6 +3031,23 @@ instantiate_virtual_regs_1 (loc, object, extra_insns)
loc = &XEXP (x, 0);
goto restart;
case USE:
case CLOBBER:
/* If the operand is a MEM, see if the change is a valid MEM. If not,
go ahead and make the invalid one, but do it to a copy. For a REG,
just make the recursive call, since there's no chance of a problem. */
if ((GET_CODE (XEXP (x, 0)) == MEM
&& instantiate_virtual_regs_1 (&XEXP (XEXP (x, 0), 0), XEXP (x, 0),
0))
|| (GET_CODE (XEXP (x, 0)) == REG
&& instantiate_virtual_regs_1 (&XEXP (x, 0), 0, 0)))
return 1;
XEXP (x, 0) = copy_rtx (XEXP (x, 0));
loc = &XEXP (x, 0);
goto restart;
case REG:
/* Try to replace with a PLUS. If that doesn't work, compute the sum
in front of this insn and substitute the temporary. */