diff options
| -rw-r--r-- | lib/Transforms/Scalar/InstructionCombining.cpp | 7 | ||||
| -rw-r--r-- | test/Transforms/InstCombine/getelementptr-2.ll | 21 |
2 files changed, 28 insertions, 0 deletions
diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp index a02aa5d..1bfce5d 100644 --- a/lib/Transforms/Scalar/InstructionCombining.cpp +++ b/lib/Transforms/Scalar/InstructionCombining.cpp @@ -10896,6 +10896,13 @@ Instruction *InstCombiner::visitGetElementPtrInst(GetElementPtrInst &GEP) { if (Value *X = getBitCastOperand(PtrOp)) { assert(isa<PointerType>(X->getType()) && "Must be cast from pointer"); + // If the input bitcast is actually "bitcast(bitcast(x))", then we don't + // want to change the gep until the bitcasts are eliminated. + if (getBitCastOperand(X)) { + Worklist.AddValue(PtrOp); + return 0; + } + // Transform: GEP (bitcast [10 x i8]* X to [0 x i8]*), i32 0, ... // into : GEP [10 x i8]* X, i32 0, ... // diff --git a/test/Transforms/InstCombine/getelementptr-2.ll b/test/Transforms/InstCombine/getelementptr-2.ll new file mode 100644 index 0000000..4cffbcd --- /dev/null +++ b/test/Transforms/InstCombine/getelementptr-2.ll @@ -0,0 +1,21 @@ +; RUN: llvm-as < %s | opt -instcombine | llvm-dis | not grep load +; PR4748 +target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128" +target triple = "i386-apple-darwin9" + %struct.B = type { double } + %struct.A = type { %struct.B, i32, i32 } + +define i32 @_Z4funcv(%struct.A* %a) { +entry: + %g3 = getelementptr %struct.A* %a, i32 0, i32 1 + store i32 10, i32* %g3, align 4 + + %g4 = getelementptr %struct.A* %a, i32 0, i32 0 + + %new_a = bitcast %struct.B* %g4 to %struct.A* + + %g5 = getelementptr %struct.A* %new_a, i32 0, i32 1 + %a_a = load i32* %g5, align 4 + ret i32 %a_a +} + |