[LLVMdev] Combining physical registers
kparzysz at codeaurora.org
Thu May 16 08:13:25 PDT 2013
The function TII::canCombineSubRegIndices has been gone for a while now,
and I was wondering if there is a target-independent way of determining
if a certain set of physical registers "adds up" to a larger register.
For example, on X86, AL and AH together form AX. On Hexagon, R0 and R1
The context here is an attempt to coalesce multiple loads/stores into
fewer loads/stores using larger registers.
It is my understanding that register lane masks are not exact in a sense
that they will tell me if two register lanes alias, but not necessarily
if a set of masks adds up to a full register. Is this correct?
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