Bug 891707
| Summary: | stdout redirect error | ||||||
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| Product: | [Fedora] Fedora | Reporter: | Michael Parkinson <Thumbtack2007> | ||||
| Component: | gcc | Assignee: | Jakub Jelinek <jakub> | ||||
| Status: | CLOSED NOTABUG | QA Contact: | Fedora Extras Quality Assurance <extras-qa> | ||||
| Severity: | high | Docs Contact: | |||||
| Priority: | unspecified | ||||||
| Version: | 17 | CC: | jakub, law | ||||
| Target Milestone: | --- | ||||||
| Target Release: | --- | ||||||
| Hardware: | i686 | ||||||
| OS: | Linux | ||||||
| Whiteboard: | |||||||
| Fixed In Version: | Doc Type: | Bug Fix | |||||
| Doc Text: | Story Points: | --- | |||||
| Clone Of: | Environment: | ||||||
| Last Closed: | 2013-01-09 11:15:32 UTC | Type: | Bug | ||||
| Regression: | --- | Mount Type: | --- | ||||
| Documentation: | --- | CRM: | |||||
| Verified Versions: | Category: | --- | |||||
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |||||
| Cloudforms Team: | --- | Target Upstream Version: | |||||
| Embargoed: | |||||||
| Attachments: |
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Important note: also does not occur when the optimization level is -O2 Please read http://gcc.gnu.org/PR323 If you can't tolerate excess precision effects, you either need to avoid i?86, or use -msse2 -mfpmath=sse and limit yourself to CPUs with SSE2 support, or use -ffloat-store. If you can tolerate excess precision effects, but need what the C standards mandates for them, you can use -std=c99 or -fexcess-precision=standard |
Created attachment 672144 [details] contains all routines, compile script, run script; also contains 32 bit executable Description of problem: results of calculation displayed after redirect to a file are different than the results displayed when stdout goes directly to a terminal window Version-Release number of selected component (if applicable): Fedora 3.6.10-2.fc17.i686, gcc (GCC) 4.7.2 20120921 (Red Hat 4.7.2-2) How reproducible: run enclosed script; should also happen if you run enclosed 32 bit executable Steps to Reproduce: 1. run script lusolve.bug.run in terminal window 2. look at results on the screen; they should be the same 3. notice that they are not Actual results: 1:1 7.0016212 +- 0.24727210E-02 1:2 -0.22314226E-02 +- 0.27870338E-02 1:4 -0.72836803E-04 +- 0.12898492E-03 1:5 -0.99971462E-02 +- 0.58309151E-05 1:6 1.0006572 +- 0.96526108E-03 average error in rhs 0.52919594E-03 1:1 7.0016298 +- 0.24756978E-02 1:2 -0.22461086E-02 +- 0.27903942E-02 1:4 -0.73604322E-04 +- 0.12914048E-03 1:5 -0.99971117E-02 +- 0.58379455E-05 1:6 1.0006628 +- 0.96642534E-03 average error in rhs 0.52983098E-03 Expected results: 1:1 7.0016212 +- 0.24727210E-02 1:2 -0.22314226E-02 +- 0.27870338E-02 1:4 -0.72836803E-04 +- 0.12898492E-03 1:5 -0.99971462E-02 +- 0.58309151E-05 1:6 1.0006572 +- 0.96526108E-03 average error in rhs 0.52919594E-03 1:1 7.0016212 +- 0.24727210E-02 1:2 -0.22314226E-02 +- 0.27870338E-02 1:4 -0.72836803E-04 +- 0.12898492E-03 1:5 -0.99971462E-02 +- 0.58309151E-05 1:6 1.0006572 +- 0.96526108E-03 average error in rhs 0.52919594E-03 Additional info: does not occur in double precision version of routine does not occur on x86_64 machine running same version of Fedora and same version of gcc may be a Linux redirect problem rather than a gcc problem (cannot tell; very peculiar bug)