Refactor the three main groups of code out of
NarrowSearchSpaceUsingHeuristics into separate functions.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@112439 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Scalar/LoopStrengthReduce.cpp b/lib/Transforms/Scalar/LoopStrengthReduce.cpp
index 17ff08d..56a7ecc 100644
--- a/lib/Transforms/Scalar/LoopStrengthReduce.cpp
+++ b/lib/Transforms/Scalar/LoopStrengthReduce.cpp
@@ -1367,6 +1367,9 @@
void FilterOutUndesirableDedicatedRegisters();
size_t EstimateSearchSpaceComplexity() const;
+ void NarrowSearchSpaceByDetectingSupersets();
+ void NarrowSearchSpaceByCollapsingUnrolledCode();
+ void NarrowSearchSpaceByPickingWinnerRegs();
void NarrowSearchSpaceUsingHeuristics();
void SolveRecurse(SmallVectorImpl<const Formula *> &Solution,
@@ -2905,11 +2908,11 @@
return Power;
}
-/// NarrowSearchSpaceUsingHeuristics - If there are an extraordinary number of
-/// formulae to choose from, use some rough heuristics to prune down the number
-/// of formulae. This keeps the main solver from taking an extraordinary amount
-/// of time in some worst-case scenarios.
-void LSRInstance::NarrowSearchSpaceUsingHeuristics() {
+/// NarrowSearchSpaceByDetectingSupersets - When one formula uses a superset
+/// of the registers of another formula, it won't help reduce register
+/// pressure (though it may not necessarily hurt register pressure); remove
+/// it to simplify the system.
+void LSRInstance::NarrowSearchSpaceByDetectingSupersets() {
if (EstimateSearchSpaceComplexity() >= ComplexityLimit) {
DEBUG(dbgs() << "The search space is too complex.\n");
@@ -2967,7 +2970,12 @@
DEBUG(dbgs() << "After pre-selection:\n";
print_uses(dbgs()));
}
+}
+/// NarrowSearchSpaceByCollapsingUnrolledCode - When there are many registers
+/// for expressions like A, A+1, A+2, etc., allocate a single register for
+/// them.
+void LSRInstance::NarrowSearchSpaceByCollapsingUnrolledCode() {
if (EstimateSearchSpaceComplexity() >= ComplexityLimit) {
DEBUG(dbgs() << "The search space is too complex.\n");
@@ -3038,7 +3046,12 @@
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.
+void LSRInstance::NarrowSearchSpaceByPickingWinnerRegs() {
// With all other options exhausted, loop until the system is simple
// enough to handle.
SmallPtrSet<const SCEV *, 4> Taken;
@@ -3100,6 +3113,16 @@
}
}
+/// NarrowSearchSpaceUsingHeuristics - If there are an extraordinary number of
+/// formulae to choose from, use some rough heuristics to prune down the number
+/// of formulae. This keeps the main solver from taking an extraordinary amount
+/// of time in some worst-case scenarios.
+void LSRInstance::NarrowSearchSpaceUsingHeuristics() {
+ NarrowSearchSpaceByDetectingSupersets();
+ NarrowSearchSpaceByCollapsingUnrolledCode();
+ NarrowSearchSpaceByPickingWinnerRegs();
+}
+
/// SolveRecurse - This is the recursive solver.
void LSRInstance::SolveRecurse(SmallVectorImpl<const Formula *> &Solution,
Cost &SolutionCost,