diff options
| -rw-r--r-- | lib/Transforms/Utils/SimplifyCFG.cpp | 21 | ||||
| -rw-r--r-- | test/Transforms/SimplifyCFG/PR16069.ll | 14 |
2 files changed, 33 insertions, 2 deletions
diff --git a/lib/Transforms/Utils/SimplifyCFG.cpp b/lib/Transforms/Utils/SimplifyCFG.cpp index 18f334e..96570fe 100644 --- a/lib/Transforms/Utils/SimplifyCFG.cpp +++ b/lib/Transforms/Utils/SimplifyCFG.cpp @@ -1081,9 +1081,9 @@ static bool HoistThenElseCodeToIf(BranchInst *BI) { (isa<InvokeInst>(I1) && !isSafeToHoistInvoke(BB1, BB2, I1, I2))) return false; - // If we get here, we can hoist at least one instruction. BasicBlock *BIParent = BI->getParent(); + bool Changed = false; do { // If we are hoisting the terminator instruction, don't move one (making a // broken BB), instead clone it, and remove BI. @@ -1098,6 +1098,7 @@ static bool HoistThenElseCodeToIf(BranchInst *BI) { I2->replaceAllUsesWith(I1); I1->intersectOptionalDataWith(I2); I2->eraseFromParent(); + Changed = true; I1 = BB1_Itr++; I2 = BB2_Itr++; @@ -1117,7 +1118,23 @@ static bool HoistThenElseCodeToIf(BranchInst *BI) { HoistTerminator: // It may not be possible to hoist an invoke. if (isa<InvokeInst>(I1) && !isSafeToHoistInvoke(BB1, BB2, I1, I2)) - return true; + return Changed; + + for (succ_iterator SI = succ_begin(BB1), E = succ_end(BB1); SI != E; ++SI) { + PHINode *PN; + for (BasicBlock::iterator BBI = SI->begin(); + (PN = dyn_cast<PHINode>(BBI)); ++BBI) { + Value *BB1V = PN->getIncomingValueForBlock(BB1); + Value *BB2V = PN->getIncomingValueForBlock(BB2); + if (BB1V == BB2V) + continue; + + if (isa<ConstantExpr>(BB1V) && !isSafeToSpeculativelyExecute(BB1V)) + return Changed; + if (isa<ConstantExpr>(BB2V) && !isSafeToSpeculativelyExecute(BB2V)) + return Changed; + } + } // Okay, it is safe to hoist the terminator. Instruction *NT = I1->clone(); diff --git a/test/Transforms/SimplifyCFG/PR16069.ll b/test/Transforms/SimplifyCFG/PR16069.ll new file mode 100644 index 0000000..4e9f896 --- /dev/null +++ b/test/Transforms/SimplifyCFG/PR16069.ll @@ -0,0 +1,14 @@ +; RUN: opt < %s -simplifycfg -S | FileCheck %s + +; CHECK-NOT: select +@b = extern_weak global i32 +define i32 @foo(i1 %y) { + br i1 %y, label %bb1, label %bb2 +bb1: + br label %bb3 +bb2: + br label %bb3 +bb3: + %cond.i = phi i32 [ 0, %bb1 ], [ srem (i32 1, i32 zext (i1 icmp eq (i32* @b, i32* null) to i32)), %bb2 ] + ret i32 %cond.i +} |