#include "llvm/Analysis/Dominators.h"
#include "llvm/Support/PatternMatch.h"
#include "llvm/Support/ValueHandle.h"
+#include "llvm/Target/TargetData.h"
using namespace llvm;
using namespace llvm::PatternMatch;
//if (isa<UndefValue>(Ops[0]))
// return UndefValue::get(GEP.getType());
- // getelementptr P, 0 -> P.
- if (NumOps == 2)
+ if (NumOps == 2) {
+ // getelementptr P, 0 -> P.
if (ConstantInt *C = dyn_cast<ConstantInt>(Ops[1]))
if (C->isZero())
return Ops[0];
+ // getelementptr P, N -> P if P points to a type of zero size.
+ if (TD) {
+ const Type *Ty = cast<PointerType>(Ops[0]->getType())->getElementType();
+ if (Ty->isSized() && !TD->getTypeAllocSize(Ty))
+ return Ops[0];
+ }
+ }
// Check to see if this is constant foldable.
for (unsigned i = 0; i != NumOps; ++i)
--- /dev/null
+; RUN: opt < %s -instcombine -S | not grep getelementptr
+
+target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128"
+
+define {}* @foo({}* %x, i32 %n) {
+ %p = getelementptr {}* %x, i32 %n
+ ret {}* %p
+}