Add getUnrollingPreferences to TTI
Allow targets to customize the default behavior of the generic loop unrolling
transformation. This will be used by the PowerPC backend when targeting the A2
core (which is in-order with a deep pipeline), and using more aggressive
defaults is important.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@190542 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Scalar/LoopUnrollPass.cpp b/lib/Transforms/Scalar/LoopUnrollPass.cpp
index 80d060b..d47a3c3 100644
--- a/lib/Transforms/Scalar/LoopUnrollPass.cpp
+++ b/lib/Transforms/Scalar/LoopUnrollPass.cpp
@@ -55,6 +55,9 @@
CurrentAllowPartial = (P == -1) ? UnrollAllowPartial : (bool)P;
UserThreshold = (T != -1) || (UnrollThreshold.getNumOccurrences() > 0);
+ UserAllowPartial = (P != -1) ||
+ (UnrollAllowPartial.getNumOccurrences() > 0);
+ UserCount = (C != -1) || (UnrollCount.getNumOccurrences() > 0);
initializeLoopUnrollPass(*PassRegistry::getPassRegistry());
}
@@ -75,7 +78,9 @@
unsigned CurrentCount;
unsigned CurrentThreshold;
bool CurrentAllowPartial;
+ bool UserCount; // CurrentCount is user-specified.
bool UserThreshold; // CurrentThreshold is user-specified.
+ bool UserAllowPartial; // CurrentAllowPartial is user-specified.
bool runOnLoop(Loop *L, LPPassManager &LPM);
@@ -145,16 +150,24 @@
<< "] Loop %" << Header->getName() << "\n");
(void)Header;
+ TargetTransformInfo::UnrollingPreferences UP;
+ UP.Threshold = CurrentThreshold;
+ UP.OptSizeThreshold = OptSizeUnrollThreshold;
+ UP.Count = CurrentCount;
+ UP.Partial = CurrentAllowPartial;
+ UP.Runtime = UnrollRuntime;
+ TTI.getUnrollingPreferences(L, UP);
+
// Determine the current unrolling threshold. While this is normally set
// from UnrollThreshold, it is overridden to a smaller value if the current
// function is marked as optimize-for-size, and the unroll threshold was
// not user specified.
- unsigned Threshold = CurrentThreshold;
+ unsigned Threshold = UserThreshold ? CurrentThreshold : UP.Threshold;
if (!UserThreshold &&
Header->getParent()->getAttributes().
hasAttribute(AttributeSet::FunctionIndex,
Attribute::OptimizeForSize))
- Threshold = OptSizeUnrollThreshold;
+ Threshold = UP.OptSizeThreshold;
// Find trip count and trip multiple if count is not available
unsigned TripCount = 0;
@@ -167,11 +180,15 @@
TripCount = SE->getSmallConstantTripCount(L, LatchBlock);
TripMultiple = SE->getSmallConstantTripMultiple(L, LatchBlock);
}
+
+ bool Runtime = UnrollRuntime.getNumOccurrences() == 0 ?
+ UP.Runtime : UnrollRuntime;
+
// Use a default unroll-count if the user doesn't specify a value
// and the trip count is a run-time value. The default is different
// for run-time or compile-time trip count loops.
- unsigned Count = CurrentCount;
- if (UnrollRuntime && CurrentCount == 0 && TripCount == 0)
+ unsigned Count = UserCount ? CurrentCount : UP.Count;
+ if (Runtime && Count == 0 && TripCount == 0)
Count = UnrollRuntimeCount;
if (Count == 0) {
@@ -204,7 +221,8 @@
if (TripCount != 1 && Size > Threshold) {
DEBUG(dbgs() << " Too large to fully unroll with count: " << Count
<< " because size: " << Size << ">" << Threshold << "\n");
- if (!CurrentAllowPartial && !(UnrollRuntime && TripCount == 0)) {
+ bool AllowPartial = UserAllowPartial ? CurrentAllowPartial : UP.Partial;
+ if (!AllowPartial && !(Runtime && TripCount == 0)) {
DEBUG(dbgs() << " will not try to unroll partially because "
<< "-unroll-allow-partial not given\n");
return false;
@@ -215,7 +233,7 @@
while (Count != 0 && TripCount%Count != 0)
Count--;
}
- else if (UnrollRuntime) {
+ else if (Runtime) {
// Reduce unroll count to be a lower power-of-two value
while (Count != 0 && Size > Threshold) {
Count >>= 1;
@@ -231,7 +249,7 @@
}
// Unroll the loop.
- if (!UnrollLoop(L, Count, TripCount, UnrollRuntime, TripMultiple, LI, &LPM))
+ if (!UnrollLoop(L, Count, TripCount, Runtime, TripMultiple, LI, &LPM))
return false;
return true;