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Tree SSA If-combine optimization pass in GCC
- From: Ajit Kumar Agarwal <ajit dot kumar dot agarwal at xilinx dot com>
- To: Richard Biener <richard dot guenther at gmail dot com>, "gcc at gcc dot gnu dot org" <gcc at gcc dot gnu dot org>
- Cc: Vinod Kathail <vinodk at xilinx dot com>, Shail Aditya Gupta <shailadi at xilinx dot com>, Vidhumouli Hunsigida <vidhum at xilinx dot com>, "Nagaraju Mekala" <nmekala at xilinx dot com>
- Date: Tue, 17 Feb 2015 08:22:52 +0000
- Subject: Tree SSA If-combine optimization pass in GCC
- Authentication-results: sourceware.org; auth=none
- Authentication-results: spf=pass (sender IP is 18.104.22.168) smtp dot mailfrom=ajit dot kumar dot agarwal at xilinx dot com;
I can see the IF-combining (If-merging) pass of optimization on tree-ssa form of intermediate representation.
The IF-combine or merging takes of merging the IF-THEN-ELSE if the condition Expr found be congruent or
The IF-combine happens if the two IF-THEN-ELSE are contiguous to each other.
If the IF-THEN-ELSE happens to be not contiguous but are wide apart with there is code in between.
Does the If-combine takes care of this. This requires to do the head-duplication and Tail-duplication for the
Code in between If-THEN-ELSE to bring the IF-THEN-ELSE contiguous to each other.
After the head and tail duplication of the code in between the IF-THEN-ElSE sequence becomes contiguous
to each other. Apart from this, Does the tree-ssa-if-combine pass considers the control flow of the body
of the IF-THEN-ELSE. Is there any limitation on control flow of the body of the IF-THEN-ELSE.
Can I know the scope of tree-ssa-ifcombine optimizations pass with respect to the above points.
Thanks & Regards