[PATCH] fold: sqrt(x * x * y) -> fabs(x) * sqrt(y)

[hfinkel at anl.gov]

Adding for the record...

================
Comment at: lib/Transforms/InstCombine/InstCombineMulDivRem.cpp:453
@@ +452,3 @@
+  // A function-level attribute overrides the instruction-level fast-math-flags.
+  // This can happen when code is inlined via LTO.
+  if (!AllowReassociate) {
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As we discussed elsewhere (PR21291), this is incorrect.

http://reviews.llvm.org/D5787