Displaying 2 results from an estimated 2 matches for "outofloop".
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outerloop
2004 Jul 09
0
[LLVMdev] PHI nodes in machine code
...> into copy instructions in predecessors -- all of which will have the same
> destination register.
There are algorithms for eliminating PHI nodes, but they aren't quite so
simple. Consider what happens when you have phi nodes in a block like
this:
Loop:
A = phi (B, Loop), (0, OutOfLoop)
B = phi (A, Loop), (1, OutOfLoop)
...
br Loop
No matter how you insert copies in the predecessors, you can't maintain
the semantics of the phis (which are simultaneous assignment). This is
obviously possible to handle, it's just not entirely trivial. FWIW, this
is kno...
2004 Jul 09
2
[LLVMdev] PHI nodes in machine code
Misha Brukman wrote:
> LLVM Machine code is in SSA.
This explains quite a lot. I though it's possible to just reduce convert phis
into copy instructions in predecessors -- all of which will have the same
destination register.
> gets you two definitions of r. So we have machine PHI nodes merge the
> two possible values into one for result of r. These phis get removed
> after