Revert "[PPC] Give unaligned memory access lower cost on processor that supports it"

This reverts commit r292680. It is causing significantly worse
performance and test timeouts in our internal builds. I have already
routed reproduction instructions your way.

llvm-svn: 293092

Author: djasper-gh

llvm/lib/Target/PowerPC/PPCTargetTransformInfo.cpp

@@ -401,10 +401,6 @@ int PPCTTIImpl::getMemoryOpCost(unsigned Opcode, Type *Src, unsigned Alignment,
   if (IsVSXType || (ST->hasVSX() && IsAltivecType))
     return Cost;
 
-  // Newer PPC supports unaligned memory access.
-  if (TLI->allowsMisalignedMemoryAccesses(LT.second, 0))
-    return Cost;
-
   // PPC in general does not support unaligned loads and stores. They'll need
   // to be decomposed based on the alignment factor.
 

llvm/test/Analysis/CostModel/PowerPC/load_store.ll

@@ -1,4 +1,4 @@
-; RUN: opt < %s  -cost-model -analyze -mtriple=powerpc64-unknown-linux-gnu -mcpu=g5 -disable-ppc-unaligned | FileCheck %s
+; RUN: opt < %s  -cost-model -analyze -mtriple=powerpc64-unknown-linux-gnu -mcpu=g5 | FileCheck %s
 target datalayout = "E-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-f128:128:128-v128:128:128-n32:64"
 target triple = "powerpc64-unknown-linux-gnu"