Ah right, I forgot @code_lowered even existed , thanks for that. Yeah gcc/clang all have the same native code from this snippet, which is why I was surprised that the same julia code was produced different code native.
On Tuesday, October 4, 2016 at 9:13:17 AM UTC-4, Isaiah wrote: > > These expressions are lowered differently because `test2` gets a temporary > due to the conditional reassignment of `u`, whereas `test1` is just a > straight line switch and jump (look at `code_lowered` and `code_typed`). > > For the same C code, the lowered IR from Clang looks similar, but it > appears to constant fold and reduce down to identical assembly at `-O1` and > above. The fact that Julia doesn't is probably due to difference in LLVM > optimization passes or order. > > As far as style, personally I think the first one is cleaner. > > On Fri, Sep 30, 2016 at 1:48 PM, mmh <mum...@gmail.com <javascript:>> > wrote: > >> I would have that thought that these two function would produce the same >> code, but they do not. >> >> Could someone care to explain the difference and which is preferred and >> why >> >> >> http://pastebin.com/GJ8YPfV3 >> >> function test1(x) >> y = 2.0 >> u = 2.320 >> x < 0 && (u = 32.0) >> x > 1 && (u = 1.0) >> return u + y >> end >> >> >> function test2(x) >> y = 2.0 >> u = 2.320 >> u = x < 0 ? 32.0 : u >> u = x > 1 ? 1.0 : u >> return u + y >> end >> >> >> @code_llvm test1(2.2) >> >> @code_llvm test2(2.2) >> >> >
