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Re: define_split

From: Paolo Bonzini <bonzini at gnu dot org>
To: Joern Rennecke <amylaar at spamcop dot net>
Cc: roy rosen <roy dot 1rosen at gmail dot com>, Michael Meissner <meissner at linux dot vnet dot ibm dot com>, gcc at gcc dot gnu dot org
Date: Tue, 09 Nov 2010 17:57:17 +0100
Subject: Re: define_split
References: <AANLkTinXSp9FefVHXWMm1FL-A040r+1wzoi1juyUuBL+@mail.gmail.com> <20101108201655.GA14062@hungry-tiger.westford.ibm.com> <AANLkTi=Wa2tNAHJNzo0sWt7=3099vJSHMLs6ag8y3Gxj@mail.gmail.com> <20101109042209.8ud7scl0ckksko4w-nzlynne@webmail.spamcop.net> <4CD96EAC.3070602@gnu.org> <20101109113804.0oamo2x3c4gos8kc-nzlynne@webmail.spamcop.net>

On 11/09/2010 05:38 PM, Joern Rennecke wrote:

A define_insn will be recognized in all contexts.
Having an insn pattern for an insn that does not actually exist can cause
all kinds of unintended consequences as the optimizers try to generate
and recognize 'optimized' patterns, or when reload does its stuff.

Before reload that is not a problem at all, I think, actually it can be an advantage. At reload or after, the only problem I see is if someone is sloppy with constraints.

Paolo

Follow-Ups:
- Re: define_split
  - From: Joern Rennecke

References:
- Re: define_split
  - From: Michael Meissner
- Re: define_split
  - From: roy rosen
- Re: define_split
  - From: Joern Rennecke
- Re: define_split
  - From: Paolo Bonzini
- Re: define_split
  - From: Joern Rennecke

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