[SystemZ] Implementation of getUnrollingPreferences().
This commit enables more unrolling for SystemZ by implementing the
SystemZTargetTransformInfo::getUnrollingPreferences() method.
It has been found that it is better to only unroll moderately, so the
DefaultUnrollRuntimeCount has been moved into UnrollingPreferences in order
to set this to a lower value for SystemZ (4).
Reviewers: Evgeny Stupachenko, Ulrich Weigand.
https://reviews.llvm.org/D24451
llvm-svn: 282570
diff --git a/llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp b/llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp
index dbbffee..a8442e6 100644
--- a/llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp
@@ -102,10 +102,6 @@
/// code expansion would result.
static const unsigned NoThreshold = UINT_MAX;
-/// Default unroll count for loops with run-time trip count if
-/// -unroll-count is not set
-static const unsigned DefaultUnrollRuntimeCount = 8;
-
/// Gather the various unrolling parameters based on the defaults, compiler
/// flags, TTI overrides and user specified parameters.
static TargetTransformInfo::UnrollingPreferences gatherUnrollingPreferences(
@@ -122,6 +118,7 @@
UP.PartialThreshold = UP.Threshold;
UP.PartialOptSizeThreshold = 0;
UP.Count = 0;
+ UP.DefaultUnrollRuntimeCount = 8;
UP.MaxCount = UINT_MAX;
UP.FullUnrollMaxCount = UINT_MAX;
UP.Partial = false;
@@ -803,7 +800,7 @@
// largest power-of-two factor that satisfies the threshold limit.
// As we'll create fixup loop, do the type of unrolling only if
// remainder loop is allowed.
- UP.Count = DefaultUnrollRuntimeCount;
+ UP.Count = UP.DefaultUnrollRuntimeCount;
UnrolledSize = (LoopSize - BEInsns) * UP.Count + BEInsns;
while (UP.Count != 0 && UnrolledSize > UP.PartialThreshold) {
UP.Count >>= 1;
@@ -852,7 +849,7 @@
return false;
}
if (UP.Count == 0)
- UP.Count = DefaultUnrollRuntimeCount;
+ UP.Count = UP.DefaultUnrollRuntimeCount;
UnrolledSize = (LoopSize - BEInsns) * UP.Count + BEInsns;
// Reduce unroll count to be the largest power-of-two factor of