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When GVN wants to re-interpret an already available value in a smaller type, it needs to right-shift the value on big-endian systems to ensure the correct bytes are accessed. The shift value is the difference of the sizes of the two types. This is correct as long as both types occupy multiples of full bytes. However, when one of them is a sub-byte type like i1, this no longer holds true: we still need to shift, but only to access the correct *byte*. Accessing bits within the byte requires no shift in either endianness; e.g. an i1 resides in the least-significant bit of its containing byte on both big- and little-endian systems. Therefore, the appropriate shift value to be used is the difference of the *storage* sizes of the two types. This is already handled correctly in one place where such a shift takes place (GetStoreValueForLoad), but is incorrect in two other places: GetLoadValueForLoad and CoerceAvailableValueToLoadType. This patch changes both places to use the storage size as well. Differential Revision: http://reviews.llvm.org/D18662 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@265684 91177308-0d34-0410-b5e6-96231b3b80d8
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