The current IRSimilarityIdentifier does not try to find similarity across blocks, this patch provides a mechanism to compare two branches against one another, to find similarity across basic blocks, rather than just within them.
This adds a step in the similarity identification process that labels all of the basic blocks so that we can identify the relative branching locations. Within an IRSimilarityCandidate we use these relative locations to determine whether if the branching to other relative locations in the same region is the same between branches. If they are, we consider them similar.
We do not consider the relative location of the branch if the target branch is outside of the region. In this case, both branches must exit to a location outside the region, but the exact relative location does not matter.
Reviewers: paquette, yroux
Differential Revision: https://reviews.llvm.org/D106989
This adds a cost model that takes into account the total number of
machine instructions to be removed from each region, the number of
instructions added by adding a new function with a set of instructions,
and the instructions added by handling arguments.
Tests not adding flags:
llvm/test/Transforms/IROutliner/outlining-cost-model.ll
Reviewers: jroelofs, paquette
Differential Revision: https://reviews.llvm.org/D87299
Extracted regions can have both inputs and outputs. In addition, the
CodeExtractor removes inputs that are only used in llvm.assumes, and
sunken allocas (values are used entirely in the extracted region as
denoted by lifetime intrinsics). We also cannot combine sections that
have different constants in the same structural location, and these
constants will have to elevated to argument. This patch deduplicates
extracted functions that only have inputs and non of the special cases.
We test that correctly deduplicate in:
test/Transforms/IROutliner/outlining-same-globals.ll
test/Transforms/IROutliner/outlining-same-constants.ll
test/Transforms/IROutliner/outlining-different-structure.ll
Reviewers: jroelofs, paquette
Differential Revision: https://reviews.llvm.org/D86978
Extracted regions can have both inputs and outputs. In addition, the
CodeExtractor removes inputs that are only used in llvm.assumes, and
sunken allocas (values are used entirely in the extracted region as
denoted by lifetime intrinsics). We also cannot combine sections that
have different constants in the same structural location, and these
constants will have to elevated to argument. This patch deduplicates
extracted functions that only have inputs and non of the special cases.
We test that correctly deduplicate in:
test/Transforms/IROutliner/outlining-same-globals.ll
test/Transforms/IROutliner/outlining-same-constants.ll
test/Transforms/IROutliner/outlining-different-structure.ll
This adds a custom InstVisitor to return false on instructions that
should not be allowed to be outlined. These match the illegal
instructions in the IRInstructionMapper with exception of the addition
of the llvm.assume intrinsic.
Tests all the tests marked: illegal-*-.ll with a test for each kind of
instruction that has been marked as illegal.
Reviewers: jroelofs, paquette
Differential Revisions: https://reviews.llvm.org/D86976
Andrew Litteken