[llvm-commits] [llvm] r112441 - /llvm/trunk/lib/Transforms/Scalar/LoopStrengthReduce.cpp

[Dan Gohman]

Author: djg
Date: Sun Aug 29 11:39:22 2010
New Revision: 112441

URL: http://llvm.org/viewvc/llvm-project?rev=112441&view=rev
Log:
Optionally rerun dedicated-register filtering after applying
other filtering techniques, as those may allow it to filter
out more obviously unprofitable candidates.

Modified:
    llvm/trunk/lib/Transforms/Scalar/LoopStrengthReduce.cpp

Modified: llvm/trunk/lib/Transforms/Scalar/LoopStrengthReduce.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/LoopStrengthReduce.cpp?rev=112441&r1=112440&r2=112441&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/LoopStrengthReduce.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/LoopStrengthReduce.cpp Sun Aug 29 11:39:22 2010
@@ -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();
 }