From 95938a8732b572d61955b1de8c49362c9e162640 Mon Sep 17 00:00:00 2001 From: Xavier Leroy Date: Fri, 31 May 2019 19:15:19 +0200 Subject: If-conversion optimization Extends the instruction selection pass with an if-conversion optimization: some if/then/else statements are converted into "select" operations, which in turn can be compiled down to branchless instruction sequences if the target architecture supports them. The statements that are converted are of the form if (cond) { x = a1; } else { x = a2; } if (cond) { x = a1; } if (cond) { /*skip*/; } else { x = a2; } where a1, a2 are "safe" expressions, containing no operations that can fail at run-time, such as memory loads or integer divisions. A heuristic in backend/Selectionaux.ml controls when the optimization occurs, depending on command-line flags and the complexity of the "then" and "else" branches. --- extraction/extraction.v | 1 + 1 file changed, 1 insertion(+) (limited to 'extraction') diff --git a/extraction/extraction.v b/extraction/extraction.v index 15a64d89..c0286f7b 100644 --- a/extraction/extraction.v +++ b/extraction/extraction.v @@ -72,6 +72,7 @@ Extract Constant Iteration.GenIter.iterate => (* Selection *) Extract Constant Selection.compile_switch => "Switchaux.compile_switch". +Extract Constant Selection.if_conversion_heuristic => "Selectionaux.if_conversion_heuristic". (* RTLgen *) Extract Constant RTLgen.more_likely => "RTLgenaux.more_likely". -- cgit