[PPC64] Add support for the ICBT instruction on POWER8.

Patch by Kit Barton.

Support for the ICBT instruction is currently present, but limited to
embedded processors. This change adds a new FeatureICBT that can be used
to identify whether the ICBT instruction is available on a specific processor.

Two new tests are added:
 * Positive test to ensure the icbt instruction is present when using
-mcpu=pwr8
 * Negative test to ensure the icbt instruction is not generated when
using -mcpu=pwr7

Both test cases use the Prefetch opcode in LLVM. They are based on the
ppc64-prefetch.ll test case.

llvm-svn: 226033

1 files changed, 2 insertions, 0 deletions

diff --git a/llvm/lib/Target/PowerPC/PPCSubtarget.h b/llvm/lib/Target/PowerPC/PPCSubtarget.h
index a1b644d2685..f5dc3003a7a 100644
--- a/llvm/lib/Target/PowerPC/PPCSubtarget.h
+++ b/llvm/lib/Target/PowerPC/PPCSubtarget.h
@@ -113,6 +113,7 @@ protected:
   bool DeprecatedDST;
   bool HasLazyResolverStubs;
   bool IsLittleEndian;
+  bool HasICBT;
 
   enum {
     PPC_ABI_UNKNOWN,
@@ -230,6 +231,7 @@ public:
   bool isE500() const { return IsE500; }
   bool isDeprecatedMFTB() const { return DeprecatedMFTB; }
   bool isDeprecatedDST() const { return DeprecatedDST; }
+  bool hasICBT() const { return HasICBT; }
 
   const Triple &getTargetTriple() const { return TargetTriple; }