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different rtl files
- From: Iman Narasamdya <in at cs dot man dot ac dot uk>
- To: gcc-help at gcc dot gnu dot org
- Date: Wed, 13 Oct 2004 23:15:59 +0100
- Subject: different rtl files
Hello,
I'd like to know why the first generated rtl files of compiling the same
program with different optimization levels are syntactically different.
For example, suppose my file is file.c, and I do the following compilations:
gcc -dr file.c (a), and
gcc -O2 -dr file.c (b).
Suppose (a) is the rtl file of the first compilation and (b) is that of
the second compilation. According to my observation, (a) and (b) have
the same basic-block structure, but they are syntactically different.
Does gcc perform something else, when the option -O2 is used, before
generating the first rtl file?
Rgds,
Iman Narasamdya