[PowerPC] Turn on CR-Logical reducer pass

This re-commits r375152 which was pulled in r375233 because it broke
the EXPENSIVE_CHECKS bot on Windows.

The reason for the failure was a bug in the pass that the commit turned
on by default. This patch fixes that bug and turns the pass back on.
This patch has been verified on the buildbot that originally failed
thanks to Simon Pilgrim.

Differential revision: https://reviews.llvm.org/D52431

llvm-svn: 375497

2 files changed, 6 insertions, 5 deletions

diff --git a/llvm/lib/Target/PowerPC/PPCReduceCRLogicals.cpp b/llvm/lib/Target/PowerPC/PPCReduceCRLogicals.cpp
index ac20fae983c..3b71ed219c1 100644
--- a/llvm/lib/Target/PowerPC/PPCReduceCRLogicals.cpp
+++ b/llvm/lib/Target/PowerPC/PPCReduceCRLogicals.cpp
@@ -381,10 +381,10 @@ private:
   const MachineBranchProbabilityInfo *MBPI;
 
   // A vector to contain all the CR logical operations
-  std::vector<CRLogicalOpInfo> AllCRLogicalOps;
+  SmallVector<CRLogicalOpInfo, 16> AllCRLogicalOps;
   void initialize(MachineFunction &MFParm);
   void collectCRLogicals();
-  bool handleCROp(CRLogicalOpInfo &CRI);
+  bool handleCROp(unsigned Idx);
   bool splitBlockOnBinaryCROp(CRLogicalOpInfo &CRI);
   static bool isCRLogical(MachineInstr &MI) {
     unsigned Opc = MI.getOpcode();
@@ -398,7 +398,7 @@ private:
     // Not using a range-based for loop here as the vector may grow while being
     // operated on.
     for (unsigned i = 0; i < AllCRLogicalOps.size(); i++)
-      Changed |= handleCROp(AllCRLogicalOps[i]);
+      Changed |= handleCROp(i);
     return Changed;
   }
 
@@ -578,10 +578,11 @@ void PPCReduceCRLogicals::initialize(MachineFunction &MFParam) {
 /// a unary CR logical might be used to change the condition code on a
 /// comparison feeding it. A nullary CR logical might simply be removable
 /// if the user of the bit it [un]sets can be transformed.
-bool PPCReduceCRLogicals::handleCROp(CRLogicalOpInfo &CRI) {
+bool PPCReduceCRLogicals::handleCROp(unsigned Idx) {
   // We can definitely split a block on the inputs to a binary CR operation
   // whose defs and (single) use are within the same block.
   bool Changed = false;
+  CRLogicalOpInfo CRI = AllCRLogicalOps[Idx];
   if (CRI.IsBinary && CRI.ContainedInBlock && CRI.SingleUse && CRI.FeedsBR &&
       CRI.DefsSingleUse) {
     Changed = splitBlockOnBinaryCROp(CRI);
diff --git a/llvm/lib/Target/PowerPC/PPCTargetMachine.cpp b/llvm/lib/Target/PowerPC/PPCTargetMachine.cpp
index 01579065984..abefee8b339 100644
--- a/llvm/lib/Target/PowerPC/PPCTargetMachine.cpp
+++ b/llvm/lib/Target/PowerPC/PPCTargetMachine.cpp
@@ -93,7 +93,7 @@ EnableMachineCombinerPass("ppc-machine-combiner",
 static cl::opt<bool>
   ReduceCRLogical("ppc-reduce-cr-logicals",
                   cl::desc("Expand eligible cr-logical binary ops to branches"),
-                  cl::init(false), cl::Hidden);
+                  cl::init(true), cl::Hidden);
 extern "C" void LLVMInitializePowerPCTarget() {
   // Register the targets
   RegisterTargetMachine<PPCTargetMachine> A(getThePPC32Target());