diff options
| -rw-r--r-- | lib/Transforms/Scalar/InstructionCombining.cpp | 8 | ||||
| -rw-r--r-- | test/Transforms/InstCombine/2008-06-19-UncondLoad.ll | 16 |
2 files changed, 23 insertions, 1 deletions
diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp index 72a27f500c..54e611d2a1 100644 --- a/lib/Transforms/Scalar/InstructionCombining.cpp +++ b/lib/Transforms/Scalar/InstructionCombining.cpp @@ -10062,10 +10062,16 @@ static bool isSafeToLoadUnconditionally(Value *V, Instruction *ScanFrom) { while (BBI != E) { --BBI; + // If we see a free or a call (which might do a free) the pointer could be + // marked invalid. + if (isa<FreeInst>(BBI) || isa<CallInst>(BBI)) + return false; + if (LoadInst *LI = dyn_cast<LoadInst>(BBI)) { if (LI->getOperand(0) == V) return true; - } else if (StoreInst *SI = dyn_cast<StoreInst>(BBI)) + } else if (StoreInst *SI = dyn_cast<StoreInst>(BBI)) { if (SI->getOperand(1) == V) return true; + } } return false; diff --git a/test/Transforms/InstCombine/2008-06-19-UncondLoad.ll b/test/Transforms/InstCombine/2008-06-19-UncondLoad.ll new file mode 100644 index 0000000000..fa3dc0ae14 --- /dev/null +++ b/test/Transforms/InstCombine/2008-06-19-UncondLoad.ll @@ -0,0 +1,16 @@ +; RUN: llvm-as < %s | opt -instcombine | llvm-dis | grep load | count 3 +; PR2471 + +declare i32 @x(i32*) +define i32 @b(i32* %a, i32* %b) { +entry: + %tmp1 = load i32* %a + %tmp3 = load i32* %b + %add = add i32 %tmp1, %tmp3 + %call = call i32 @x( i32* %a ) + %tobool = icmp ne i32 %add, 0 + ; not safe to turn into an uncond load + %cond = select i1 %tobool, i32* %b, i32* %a + %tmp8 = load i32* %cond + ret i32 %tmp8 +} |