Red Hat Bugzilla – Bug 154116
gcc -Os generates bad assembler code
Last modified: 2007-11-30 17:11:03 EST
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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).
Created attachment 112816 [details]
C code to demonstrate bug
Should be fixed in gcc-3.4.4-1.