Matt Arsenault 2c2bfb8ff0 GlobalISel: Artifact combine unmerge of unmerge ... Unmerges have the same fundamental problem as G_TRUNC, and G_TRUNC could be implemented in terms of G_UNMERGE_VALUES. Reducing the number of elements in unmerge results ends up producing the original unmerge type profile, so the artifact combiner needs to eliminate the intermediate illegal registers. This avoids infinite looping in the legalizer in a future change. Assuming an unmerge has each result unmerged the same way, this ends up producing a new unmerge of the source for every definition. I'm not sure if the artifact combiner should either insert temporary merges here and erase the original merge, or if the combiner should look at uses from defs rather than defs from uses for unmerges. In a few cases this regresses from using 16-bit shifts for 8-bit values to using 32-bit shifts, but I think these can be legalized later (the other legalization rules don't try very hard to use 16-bit shifts either).		2020-09-01 11:01:33 -04:00
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llvm	GlobalISel: Artifact combine unmerge of unmerge	2020-09-01 11:01:33 -04:00
llvm-c	[ConstProp] Remove ConstantPropagation	2020-08-26 15:51:30 -07:00