[PowerPC] Update Vector Costs for P9

For the power9 CPU, vector operations consume a pair of execution units rather
than one execution unit like a scalar operation. Update the target transform
cost functions to reflect the higher cost of vector operations when targeting
Power9.

Patch by RolandF.

Differential revision: https://reviews.llvm.org/D55461

llvm-svn: 352261

1 files changed, 1 insertions, 0 deletions

diff --git a/llvm/lib/Target/PowerPC/PPCSubtarget.cpp b/llvm/lib/Target/PowerPC/PPCSubtarget.cpp
index 02c73e16e8e..94b80dd5836 100644
--- a/llvm/lib/Target/PowerPC/PPCSubtarget.cpp
+++ b/llvm/lib/Target/PowerPC/PPCSubtarget.cpp
@@ -107,6 +107,7 @@ void PPCSubtarget::initializeEnvironment() {
   IsISA3_0 = false;
   UseLongCalls = false;
   SecurePlt = false;
+  VectorsUseTwoUnits = false;
 
   HasPOPCNTD = POPCNTD_Unavailable;
 }