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Re: [PATCH 1/2] soft-fp: Fix overwritten issue for division in op-4.h

From: Joseph Myers <joseph at codesourcery dot com>
To: Zong Li <zongbox at gmail dot com>
Cc: <palmer at dabbelt dot com>, <darius at bluespec dot com>, <andrew at sifive dot com>, <dj at redhat dot com>, <libc-alpha at sourceware dot org>, <jimw at sifive dot com>, <kito at andestech dot com>, <greentime at andestech dot com>
Date: Mon, 15 Oct 2018 13:04:53 +0000
Subject: Re: [PATCH 1/2] soft-fp: Fix overwritten issue for division in op-4.h
References: <cover.1539595555.git.zongbox@gmail.com> <5e51c4ea8cfe99f2faac5e206982658bd6c5d265.1539595555.git.zongbox@gmail.com> <alpine.DEB.2.21.1810151237300.18824@digraph.polyomino.org.uk>

On Mon, 15 Oct 2018, Joseph Myers wrote:

> to be fixed.  If that choice says the overlap above it not OK, a whole 
> four-word temporary should be defined using _FP_FRAC_DECL_4 for the 
> result, and then copied with _FP_FRAC_COPY_4.  The commit message for any 

In fact, you don't need that copy from the temporary back to X, because 
the result is immediately used in a call to _FP_FRAC_SUB_4 which can 
become _FP_FRAC_SUB_4 (X, Y, _FP_DIV_MEAT_4_tmp).

-- 
Joseph S. Myers
joseph@codesourcery.com

Follow-Ups:
- Re: [PATCH 1/2] soft-fp: Fix overwritten issue for division in op-4.h
  - From: Zong Li

References:
- [PATCH 0/2] Fix up soft-fp issue.
  - From: Zong Li
- [PATCH 1/2] soft-fp: Fix overwritten issue for division in op-4.h
  - From: Zong Li
- Re: [PATCH 1/2] soft-fp: Fix overwritten issue for division in op-4.h
  - From: Joseph Myers

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