\n" if !
- - -- performs code stripping. this transformation can delete: -
- -- note that this transformation makes code much less readable, so it should - only be used in situations where the strip utility would be used, - such as reducing code size or making it harder to reverse engineer code. -
-A simple loop rotation transformation.
+ This pass performs several transformations to transform natural loops into a + simpler form, which makes subsequent analyses and transformations simpler and + more effective. +
+ ++ Loop pre-header insertion guarantees that there is a single, non-critical + entry edge from outside of the loop to the loop header. This simplifies a + number of analyses and transformations, such as LICM. +
+ ++ Loop exit-block insertion guarantees that all exit blocks from the loop + (blocks which are outside of the loop that have predecessors inside of the + loop) only have predecessors from inside of the loop (and are thus dominated + by the loop header). This simplifies transformations such as store-sinking + that are built into LICM. +
+ ++ This pass also guarantees that loops will have exactly one backedge. +
+ ++ Note that the simplifycfg pass will clean up blocks which are split out but + end up being unnecessary, so usage of this pass should not pessimize + generated code. +
+ ++ This pass obviously modifies the CFG, but updates loop information and + dominator information. +
+- This pass performs several transformations to transform natural loops into a - simpler form, which makes subsequent analyses and transformations simpler and - more effective. -
- -- Loop pre-header insertion guarantees that there is a single, non-critical - entry edge from outside of the loop to the loop header. This simplifies a - number of analyses and transformations, such as LICM. -
- -- Loop exit-block insertion guarantees that all exit blocks from the loop - (blocks which are outside of the loop that have predecessors inside of the - loop) only have predecessors from inside of the loop (and are thus dominated - by the loop header). This simplifies transformations such as store-sinking - that are built into LICM. -
- -- This pass also guarantees that loops will have exactly one backedge. -
- -- Note that the simplifycfg pass will clean up blocks which are split out but - end up being unnecessary, so usage of this pass should not pessimize - generated code. -
- -- This pass obviously modifies the CFG, but updates loop information and - dominator information. -
-This pass moves instructions into successor blocks, when possible, so that - they aren't executed on paths where their results aren't needed. -
-This pass moves instructions into successor blocks, when possible, so that + they aren't executed on paths where their results aren't needed. +
++ This pass finds functions that return a struct (using a pointer to the struct + as the first argument of the function, marked with the 'sret' attribute) and + replaces them with a new function that simply returns each of the elements of + that struct (using multiple return values). +
+ ++ This pass works under a number of conditions: +
+ ++ performs code stripping. this transformation can delete: +
+ ++ note that this transformation makes code much less readable, so it should + only be used in situations where the strip utility would be used, + such as reducing code size or making it harder to reverse engineer code. +
+- This pass finds functions that return a struct (using a pointer to the struct - as the first argument of the function, marked with the 'sret' attribute) and - replaces them with a new function that simply returns each of the elements of - that struct (using multiple return values). -
- -- This pass works under a number of conditions: -
- -