[llvm-commits] [llvm] r52703 - /llvm/trunk/lib/Transforms/Utils/SimplifyCFG.cpp

[Evan Cheng]

Author: evancheng
Date: Wed Jun 25 02:50:12 2008
New Revision: 52703

URL: http://llvm.org/viewvc/llvm-project?rev=52703&view=rev
Log:
- Use O(1) check of basic block size limit.
- Avoid speculatively execute vector ops.

Modified:
    llvm/trunk/lib/Transforms/Utils/SimplifyCFG.cpp

Modified: llvm/trunk/lib/Transforms/Utils/SimplifyCFG.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/SimplifyCFG.cpp?rev=52703&r1=52702&r2=52703&view=diff

==============================================================================
--- llvm/trunk/lib/Transforms/Utils/SimplifyCFG.cpp (original)
+++ llvm/trunk/lib/Transforms/Utils/SimplifyCFG.cpp Wed Jun 25 02:50:12 2008
@@ -965,8 +965,11 @@
 static bool SpeculativelyExecuteBB(BranchInst *BI, BasicBlock *BB1) {
   // Only speculatively execution a single instruction (not counting the
   // terminator) for now.
-  if (BB1->size() != 2)
-    return false;
+  BasicBlock::iterator BBI = BB1->begin();
+  ++BBI; // must have at least a terminator
+  if (BBI == BB1->end()) return false; // only one inst
+  ++BBI;
+  if (BBI != BB1->end()) return false; // more than 2 insts.
 
   // Be conservative for now. FP select instruction can often be expensive.
   Value *BrCond = BI->getCondition();
@@ -1006,8 +1009,9 @@
   case Instruction::Shl:
   case Instruction::LShr:
   case Instruction::AShr:
-    if (I->getOperand(0)->getType()->isFPOrFPVector())
-      return false;  // FP arithmetic might trap.
+    if (!I->getOperand(0)->getType()->isInteger())
+      // FP arithmetic might trap. Not worth doing for vector ops.
+      return false;
     break;   // These are all cheap and non-trapping instructions.
   }