Red Hat Bugzilla – Bug 164805
gcc -Os generates bad assembler code
Last modified: 2007-11-30 17:07:19 EST
+++ This bug was initially created as a clone of Bug #154116 +++
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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):
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
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).
An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on the solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.