From 90842427b2f6ab5c0aab6049fd9177033101847f Mon Sep 17 00:00:00 2001 From: Manman Ren Date: Mon, 18 Mar 2013 21:23:25 +0000 Subject: Check whether a pointer is non-null (isKnownNonNull) in isKnownNonZero. This handles the case where we have an inbounds GEP with alloca as the pointer. This fixes the regression in PR12750 and rdar://13286434. Note that we can also fix this by handling some GEP cases in isKnownNonNull. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@177321 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Analysis/ValueTracking.cpp | 2 ++ test/Transforms/InstSimplify/compare.ll | 11 +++++++++++ 2 files changed, 13 insertions(+) diff --git a/lib/Analysis/ValueTracking.cpp b/lib/Analysis/ValueTracking.cpp index 45b75df..45dcc5e 100644 --- a/lib/Analysis/ValueTracking.cpp +++ b/lib/Analysis/ValueTracking.cpp @@ -953,6 +953,8 @@ bool llvm::isKnownNonZero(Value *V, const DataLayout *TD, unsigned Depth) { // Check for pointer simplifications. if (V->getType()->isPointerTy()) { + if (isKnownNonNull(V)) + return true; if (GEPOperator *GEP = dyn_cast(V)) if (isGEPKnownNonNull(GEP, TD, Depth)) return true; diff --git a/test/Transforms/InstSimplify/compare.ll b/test/Transforms/InstSimplify/compare.ll index 0ecfb1f..b764c76 100644 --- a/test/Transforms/InstSimplify/compare.ll +++ b/test/Transforms/InstSimplify/compare.ll @@ -682,3 +682,14 @@ define zeroext i1 @external_compare(i32* noalias %x) { ; CHECK: external_compare ; CHECK: ret i1 %cmp } + +define i1 @alloca_gep(i64 %a, i64 %b) { +; CHECK: @alloca_gep +; We can prove this GEP is non-null because it is inbounds and the pointer +; is non-null. + %strs = alloca [1000 x [1001 x i8]], align 16 + %x = getelementptr inbounds [1000 x [1001 x i8]]* %strs, i64 0, i64 %a, i64 %b + %cmp = icmp eq i8* %x, null + ret i1 %cmp +; CHECK-NEXT: ret i1 false +} -- cgit v1.1