Add a target hook to allow changing the tail duplication limit based on the

contents of the block to be duplicated.  Use this for ARM Cortex A8/9 to
be more aggressive tail duplicating indirect branches, since it makes it
much more likely that they will be predicted in the branch target buffer.
Testcase coming soon.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@89187 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 5 insertions, 0 deletions

diff --git a/lib/Target/ARM/ARMSubtarget.h b/lib/Target/ARM/ARMSubtarget.h
index a95c8a5ccf..3d0e01e99b 100644
--- a/lib/Target/ARM/ARMSubtarget.h
+++ b/lib/Target/ARM/ARMSubtarget.h
@@ -50,6 +50,9 @@ protected:
   /// determine if NEON should actually be used.
   bool UseNEONForSinglePrecisionFP;
 
+  /// HasBranchTargetBuffer - True if processor can predict indirect branches.
+  bool HasBranchTargetBuffer;
+
   /// IsThumb - True if we are in thumb mode, false if in ARM mode.
   bool IsThumb;
 
@@ -123,6 +126,8 @@ protected:
   bool isThumb2() const { return IsThumb && (ThumbMode == Thumb2); }
   bool hasThumb2() const { return ThumbMode >= Thumb2; }
 
+  bool hasBranchTargetBuffer() const { return HasBranchTargetBuffer; }
+
   bool isR9Reserved() const { return IsR9Reserved; }
 
   const std::string & getCPUString() const { return CPUString; }