This is the mail archive of the gcc-patches@gcc.gnu.org mailing list for the GCC project.

Index Nav:	[Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav:	[Date Prev] [Date Next]	[Thread Prev] [Thread Next]
Other format:	[Raw text]

Re: [4.0 PATCH] Fix PR 20927

From: Mark Mitchell <mark at codesourcery dot com>
To: Ulrich Weigand <uweigand at de dot ibm dot com>
Cc: rsandifo at redhat dot com, rth at redhat dot com, gcc-patches at gcc dot gnu dot org, aj at suse dot de
Date: Tue, 12 Apr 2005 11:18:10 -0700
Subject: Re: [4.0 PATCH] Fix PR 20927
Organization: CodeSourcery, LLC
References: <200504112211.j3BMBvt7002324@53v30g15.boeblingen.de.ibm.com>

Ulrich Weigand wrote:

Richard Sandiford wrote:
      PR rtl-optimization/19683
      * reload1.c (choose_reload_regs): Pass the number of bits, not the
      number of bytes, to smallest_int_for_mode.  Fix arguments to
      REG_CANNOT_CHANGE_MODE_P.
Unfortunately, this change triggers PR 20927, an ICE on s390x
(a regression of 4.0 over 3.4).
The problematic case is where we reload:

(subreg:DF (reg:TI pseudo) 8)

When computing the "needed mode", choose_reload_regs now calls

smallest_mode_for_size (128, MODE_FLOAT)

which ICEs because the largest floating-point mode on s390x is DFmode.

Unless this manifests as a regression on a primary/secondary platform, I'm not going to include this one in 4.0.0. It could go in 4.0.1, if approved by an appropriate maintainer at that point.

--
Mark Mitchell
CodeSourcery, LLC
mark@codesourcery.com
(916) 791-8304

Follow-Ups:
- [4.0 PATCH v2] Fix PR 20927
  - From: Ulrich Weigand

References:
- [4.0 PATCH] Fix PR 20927 (was: PR19683: Fix a use of REG_CANNOT_CHANGE_MODE_P)
  - From: Ulrich Weigand

Index Nav:	[Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav:	[Date Prev] [Date Next]	[Thread Prev] [Thread Next]