Bug 593064 - Out of CLOBBERED_REGS with inline assembly
Summary: Out of CLOBBERED_REGS with inline assembly
Alias: None
Product: Fedora
Classification: Fedora
Component: gcc
Version: 13
Hardware: All
OS: Linux
Target Milestone: ---
Assignee: Jakub Jelinek
QA Contact: Fedora Extras Quality Assurance
Depends On:
TreeView+ depends on / blocked
Reported: 2010-05-17 18:22 UTC by Lubomir Rintel
Modified: 2011-06-27 16:26 UTC (History)
1 user (show)

Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Clone Of:
Last Closed: 2011-06-27 16:26:27 UTC
Type: ---

Attachments (Terms of Use)

Description Lubomir Rintel 2010-05-17 18:22:55 UTC

  int func0 (...);
  int func1 (void);
  func3 (void)
          unsigned var;
          __asm__ (
                  "" :
                  "=a" (var),
                  "=c" (var),
                  "=d" (var),
                  "=r" (var)
          func0 (
                  func1 (),
                  func1 (),
                  func1 (),
                  func1 (),
                  (var >> 8) & 0xff

$ g++ -fPIC -c -O2 repr.cpp 
repr.cpp: In function ‘void func3()’:
repr.cpp:15: error: can't find a register in class ‘CLOBBERED_REGS’ while reloading ‘asm’
repr.cpp:15: error: ‘asm’ operand has impossible constraints

Version-Release number of selected component (if applicable):


Additional info:

I've not been able to pin the problem to a specific optimization -- enabling all of "g++ -c -Q -O2 --help=optimizers" does not exhibit the problem.

Comment 1 Jakub Jelinek 2010-05-17 18:30:01 UTC
This is invalid.  You can't use the same var for more than one output operand.

Comment 2 Lubomir Rintel 2010-05-17 19:08:08 UTC
Sorry, sense was lost somewhere in the attempts to create a minimal testcase. Here's another one:

  int func0 (...);
  int func1 (void);
  func3 (void)
          unsigned var1, var2, var3, var4;
          __asm__ (
                  "" :
                  "=a" (var1),
                  "=d" (var3),
                  "=c" (var2),
                  "=r" (var4)
          func0 (
                  func1 (),
                  func1 (),
                  func1 (),
                  func1 (),
                  (var4 >> 8) & 0xff

Comment 3 Bug Zapper 2011-06-02 13:54:26 UTC
This message is a reminder that Fedora 13 is nearing its end of life.
Approximately 30 (thirty) days from now Fedora will stop maintaining
and issuing updates for Fedora 13.  It is Fedora's policy to close all
bug reports from releases that are no longer maintained.  At that time
this bug will be closed as WONTFIX if it remains open with a Fedora 
'version' of '13'.

Package Maintainer: If you wish for this bug to remain open because you
plan to fix it in a currently maintained version, simply change the 'version' 
to a later Fedora version prior to Fedora 13's end of life.

Bug Reporter: Thank you for reporting this issue and we are sorry that 
we may not be able to fix it before Fedora 13 is end of life.  If you 
would still like to see this bug fixed and are able to reproduce it 
against a later version of Fedora please change the 'version' of this 
bug to the applicable version.  If you are unable to change the version, 
please add a comment here and someone will do it for you.

Although we aim to fix as many bugs as possible during every release's 
lifetime, sometimes those efforts are overtaken by events.  Often a 
more recent Fedora release includes newer upstream software that fixes 
bugs or makes them obsolete.

The process we are following is described here: 

Comment 4 Bug Zapper 2011-06-27 16:26:27 UTC
Fedora 13 changed to end-of-life (EOL) status on 2011-06-25. Fedora 13 is 
no longer maintained, which means that it will not receive any further 
security or bug fix updates. As a result we are closing this bug.

If you can reproduce this bug against a currently maintained version of 
Fedora please feel free to reopen this bug against that version.

Thank you for reporting this bug and we are sorry it could not be fixed.

Note You need to log in before you can comment on or make changes to this bug.