[CGP] convert chain of 'if' to 'switch'; NFC

This should be extended, but CGP does some strange things,
so I'm intentionally not changing the potential order of
any transforms yet.

llvm-svn: 356566

1 files changed, 13 insertions, 14 deletions

diff --git a/llvm/lib/CodeGen/CodeGenPrepare.cpp b/llvm/lib/CodeGen/CodeGenPrepare.cpp
index 44f1709b6e9..68bab28c0b7 100644
--- a/llvm/lib/CodeGen/CodeGenPrepare.cpp
+++ b/llvm/lib/CodeGen/CodeGenPrepare.cpp
@@ -6876,6 +6876,7 @@ bool CodeGenPrepare::optimizeInst(Instruction *I, DominatorTree &DT,
   if (InsertedInsts.count(I))
     return false;
 
+  // TODO: Move into the switch on opcode below here.
   if (PHINode *P = dyn_cast<PHINode>(I)) {
     // It is possible for very late stage optimizations (such as SimplifyCFG)
     // to introduce PHI nodes too late to be cleaned up.  If we detect such a
@@ -6994,20 +6995,18 @@ bool CodeGenPrepare::optimizeInst(Instruction *I, DominatorTree &DT,
   if (tryToSinkFreeOperands(I))
     return true;
 
-  if (CallInst *CI = dyn_cast<CallInst>(I))
-    return optimizeCallInst(CI, ModifiedDT);
-
-  if (SelectInst *SI = dyn_cast<SelectInst>(I))
-    return optimizeSelectInst(SI, ModifiedDT);
-
-  if (ShuffleVectorInst *SVI = dyn_cast<ShuffleVectorInst>(I))
-    return optimizeShuffleVectorInst(SVI);
-
-  if (auto *Switch = dyn_cast<SwitchInst>(I))
-    return optimizeSwitchInst(Switch);
-
-  if (isa<ExtractElementInst>(I))
-    return optimizeExtractElementInst(I);
+  switch (I->getOpcode()) {
+  case Instruction::Call:
+    return optimizeCallInst(cast<CallInst>(I), ModifiedDT);
+  case Instruction::Select:
+    return optimizeSelectInst(cast<SelectInst>(I), ModifiedDT);
+  case Instruction::ShuffleVector:
+    return optimizeShuffleVectorInst(cast<ShuffleVectorInst>(I));
+  case Instruction::Switch:
+    return optimizeSwitchInst(cast<SwitchInst>(I));
+  case Instruction::ExtractElement:
+    return optimizeExtractElementInst(cast<ExtractElementInst>(I));
+  }
 
   return false;
 }