3 ms·
That is good to know. But while for some tasks this may be crucial, vectorization is only a part of the arsenal of optimizations gcc may apply. Recently, ther
by krylon 12y ago
That is good to know.
But while for some tasks this may be crucial, vectorization is only a part of the arsenal of optimizations gcc may apply.
Recently, there was discussion here on HN about C compilers (gcc, clang) exploiting undefined behaviour for optimizations that could be ... surprising. That, too, would be nice to know about.
The general idea of a dialogue between a programmer and a compiler about how (and where) to optimize a program is very intriguing.
- astrange 12y agogcc and clang can output before/after output for all their passes. Try '-fdump-ipa-all -fdump-tree-all -fdump-rtl-all-slim' on gcc, I forget the llvm options. It's not especially readable, though. Also, for ghc you can use '-v5' and the option that writes out C output. Prepare to be impressed(?) at how much it doesn't look like a fast C program.