Bug 154116

Summary: gcc -Os generates bad assembler code
Product: [Fedora] Fedora Reporter: D. Hugh Redelmeier <hugh>
Component: gccAssignee: Jakub Jelinek <jakub>
Status: CLOSED ERRATA QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: 3CC: sundaram
Target Milestone: ---   
Target Release: ---   
Hardware: i386   
OS: Linux   
Whiteboard:
Fixed In Version: 3.4.4-1 Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2005-09-05 08:44:10 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
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Bug Depends On:    
Bug Blocks: 164805    
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Description Flags
C code to demonstrate bug none

Description D. Hugh Redelmeier 2005-04-07 16:03:15 UTC 
From Bugzilla Helper:
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Description of problem:
For the included example, gcc generates assembler code that makes the assembler complain.  The assembler code uses an immediate value in a movb that does not fit in a byte.  The original C code does not do this.

Version-Release number of selected component (if applicable):
gcc-3.4.2-6.fc3

How reproducible:
Always

Steps to Reproduce:
1. fetch attached file "gcc-inline-bad-byte.c"
2. gcc -Os -c gcc-inline-bad-byte.c
  

Actual Results:  /tmp/ccDdmcnm.s: Assembler messages:
/tmp/ccDdmcnm.s:9: Warning: 277 shortened to 21


Expected Results:  no error messages

Additional info:

This example is boiled down from driver code being developed by the ivtv project.
Without inlining, there is no bad assembler code (I presume that the resulting code is correct, but I have not looked).
Comment 1 D. Hugh Redelmeier 2005-04-07 16:05:11 UTC 
Created attachment 112816 [details]
C code to demonstrate bug
Comment 2 Jakub Jelinek 2005-05-27 15:24:20 UTC 
Should be fixed in gcc-3.4.4-1.