This patch addresses the problem reported in PR92429.  When creating an
epilogue for vectorization we have to replace the SSA_NAMEs in the
PATTERN_DEF_SEQs and RELATED_STMTs of the epilogue's loop_vec_infos. When doing
this we were using simplify_replace_tree which always folds the replacement.
This may lead to a different tree-node than the one which was analyzed in
vect_loop_analyze.  In turn the new tree-node may require a different
vectorization than the one we had prepared for which caused the ICE in
question.

gcc/ChangeLog:
2020-01-16  Andre Vieira  <andre.simoesdiasvieira@arm.com>

	PR tree-optimization/92429
	* tree-ssa-loop-niter.h (simplify_replace_tree): Add parameter.
	* tree-ssa-loop-niter.c (simplify_replace_tree): Add parameter to
	control folding.
	* tree-vect-loop.c (update_epilogue_vinfo): Do not fold when replacing
	tree.

gcc/testsuite/ChangeLog:
2020-01-16  Andre Vieira  <andre.simoesdiasvieira@arm.com>

	PR tree-optimization/92429
	* gcc.dg/vect/pr92429.c: New test.