Issues when sum reduction is the 2nd operand of min/max

[kumasento]

This is a tricky bug, if sum reduction appears to be the 2nd operand, this assertion will fail

polymer/lib/Target/OpenScop/ConvertFromOpenScop.cc

Lines 265 to 266 in f0c09de

	assert(affExprs.size() == 1 && "A single affine expr should be returned "
	"after processing an expr in reduction.");

Instead of checking there is one expr, we should check that there is only one expr newly added.

We should change which affExpr to update as well here -

polymer/lib/Target/OpenScop/ConvertFromOpenScop.cc

Lines 279 to 280 in f0c09de

	// TODO: deal with negative terms.
	affExprs[0] = affExprs[0] + currExprs[0];