[PATCH] Use loop unrolling pragma metadata in the loop unroller (take 2)

[hfinkel at anl.gov]

================
Comment at: lib/Transforms/Scalar/LoopUnrollPass.cpp:54
@@ +53,3 @@
+static cl::opt<unsigned>
+PragmaUnrollThreshold("pragma-unroll-threshold", cl::init(4096), cl::Hidden,
+  cl::desc("Unrolled size limit for loops with an unroll(enable) or "
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4096 is much too small... we're worried about catching cases that might cause us to segfault, right? Make this at least an order of magnitude larger. You should experiment with this, take some simple loop and set the limit so that the memory size increase is limited to 200 MB or something like that.

http://reviews.llvm.org/D4147