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Re: Patch to rework mips divide patterns
- From: Jim Wilson <wilson at tuliptree dot org>
- To: Richard Sandiford <rsandifo at redhat dot com>
- Cc: echristo at redhat dot com, gcc-patches at gcc dot gnu dot org
- Date: Mon, 09 Jun 2003 13:30:58 -0700
- Subject: Re: Patch to rework mips divide patterns
- References: <wvnr864zjk6.fsf@talisman.cambridge.redhat.com>
Richard Sandiford wrote:
We have this undocumented -mcheck-range-division option.
It looks like maybe it is trying to trap on integer divide overflow.
There is only one combination of operations that can overflow MIN_INT /
-1 = MAX_INT + 1. Some hardware does give a trap for this case, some
doesn't. The code is testing the right values, but it gets the operand
number wrong for the MIN_INT check. Plus it is trapping if either
operand matches instead of trapping only if both operands match.
Jim