The IsReverseCompare flag tells CGBuiltin to swap the operands,
so that a LT/LE intrinsics can be expressed in terms of GE/GT
intrinsics.
This patch also adds builtins for the wide-variants of the compares.
Reviewers: SjoerdMeijer, efriedma, ctetreau
Reviewed By: efriedma
Tags: #clang
Differential Revision: https://reviews.llvm.org/D78747
Sander de Smalen