Optionally rerun dedicated-register filtering after applying
other filtering techniques, as those may allow it to filter
out more obviously unprofitable candidates.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@112441 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Scalar/LoopStrengthReduce.cpp b/lib/Transforms/Scalar/LoopStrengthReduce.cpp
index 8a68806..4fe93b9 100644
--- a/lib/Transforms/Scalar/LoopStrengthReduce.cpp
+++ b/lib/Transforms/Scalar/LoopStrengthReduce.cpp
@@ -1391,6 +1391,7 @@
size_t EstimateSearchSpaceComplexity() const;
void NarrowSearchSpaceByDetectingSupersets();
void NarrowSearchSpaceByCollapsingUnrolledCode();
+ void NarrowSearchSpaceByRefilteringUndesirableDedicatedRegisters();
void NarrowSearchSpaceByPickingWinnerRegs();
void NarrowSearchSpaceUsingHeuristics();
@@ -3104,6 +3105,24 @@
}
}
+/// NarrowSearchSpaceByRefilteringUndesirableDedicatedRegisters - Call
+/// FilterOutUndesirableDedicatedRegisters again, if necessary, now that
+/// we've done more filtering, as it may be able to find more formulae to
+/// eliminate.
+void LSRInstance::NarrowSearchSpaceByRefilteringUndesirableDedicatedRegisters(){
+ if (EstimateSearchSpaceComplexity() >= ComplexityLimit) {
+ DEBUG(dbgs() << "The search space is too complex.\n");
+
+ DEBUG(dbgs() << "Narrowing the search space by re-filtering out "
+ "undesirable dedicated registers.\n");
+
+ FilterOutUndesirableDedicatedRegisters();
+
+ DEBUG(dbgs() << "After pre-selection:\n";
+ print_uses(dbgs()));
+ }
+}
+
/// NarrowSearchSpaceByPickingWinnerRegs - Pick a register which seems likely
/// to be profitable, and then in any use which has any reference to that
/// register, delete all formulae which do not reference that register.
@@ -3176,6 +3195,7 @@
void LSRInstance::NarrowSearchSpaceUsingHeuristics() {
NarrowSearchSpaceByDetectingSupersets();
NarrowSearchSpaceByCollapsingUnrolledCode();
+ NarrowSearchSpaceByRefilteringUndesirableDedicatedRegisters();
NarrowSearchSpaceByPickingWinnerRegs();
}