[TTI] Add getCacheLineSize

Summary:
And use it in PPCLoopDataPrefetch.cpp.

@hfinkel, please let me know if your preference would be to preserve the
ppc-loop-prefetch-cache-line option in order to be able to override the
value of TTI::getCacheLineSize for PPC.

Reviewers: hfinkel

Subscribers: hulx2000, mcrosier, mssimpso, hfinkel, llvm-commits

Differential Revision: http://reviews.llvm.org/D16306

llvm-svn: 258419

1 files changed, 12 insertions, 0 deletions

diff --git a/llvm/lib/Target/PowerPC/PPCTargetTransformInfo.cpp b/llvm/lib/Target/PowerPC/PPCTargetTransformInfo.cpp
index cd86dabd5ab..b60c07c3672 100644
--- a/llvm/lib/Target/PowerPC/PPCTargetTransformInfo.cpp
+++ b/llvm/lib/Target/PowerPC/PPCTargetTransformInfo.cpp
@@ -21,6 +21,12 @@ using namespace llvm;
 static cl::opt<bool> DisablePPCConstHoist("disable-ppc-constant-hoisting",
 cl::desc("disable constant hoisting on PPC"), cl::init(false), cl::Hidden);
 
+// This is currently only used for the data prefetch pass which is only enabled
+// for BG/Q by default.
+static cl::opt<unsigned>
+CacheLineSize("ppc-loop-prefetch-cache-line", cl::Hidden, cl::init(64),
+              cl::desc("The loop prefetch cache line size"));
+
 //===----------------------------------------------------------------------===//
 //
 // PPC cost model.
@@ -230,6 +236,12 @@ unsigned PPCTTIImpl::getRegisterBitWidth(bool Vector) {
 
 }
 
+unsigned PPCTTIImpl::getCacheLineSize() {
+  // This is currently only used for the data prefetch pass which is only
+  // enabled for BG/Q by default.
+  return CacheLineSize;
+}
+
 unsigned PPCTTIImpl::getMaxInterleaveFactor(unsigned VF) {
   unsigned Directive = ST->getDarwinDirective();
   // The 440 has no SIMD support, but floating-point instructions