[InlineFunction] Don't add lifetime markers for zero-sized allocas.

This commit fixes the code which adds lifetime markers in InlineFunction to skip
zero-sized allocas instead of asserting on them.

rdar://problem/20531155

llvm-svn: 235312

llvm/lib/Transforms/Utils/InlineFunction.cpp

@@ -1167,7 +1167,11 @@ bool llvm::InlineFunction(CallSite CS, InlineFunctionInfo &IFI,
         Type *AllocaType = AI->getAllocatedType();
         uint64_t AllocaTypeSize = DL.getTypeAllocSize(AllocaType);
         uint64_t AllocaArraySize = AIArraySize->getLimitedValue();
-        assert(AllocaArraySize > 0 && "array size of AllocaInst is zero");
+
+        // Don't add markers for zero-sized allocas.
+        if (AllocaArraySize == 0)
+          continue;
+
         // Check that array size doesn't saturate uint64_t and doesn't
         // overflow when it's multiplied by type size.
         if (AllocaArraySize != ~0ULL &&

llvm/test/Transforms/Inline/crash-lifetime-marker.ll

@@ -0,0 +1,24 @@
+; RUN: opt < %s -inline -S | FileCheck %s
+
+; InlineFunction would assert inside the loop that leaves lifetime markers if
+; there was an zero-sized AllocaInst. Check that it doesn't assert and doesn't
+; leave lifetime markers in that case.
+
+declare i32 @callee2(i8*)
+
+define i32 @callee1(i32 %count) {
+  %a0 = alloca i8, i32 %count, align 4
+  %call0 = call i32 @callee2(i8* %a0)
+  ret i32 %call0
+}
+
+; CHECK-LABEL: define i32 @caller1(
+; CHECK: [[ALLOCA:%[a-z0-9\.]+]] = alloca i8
+; CHECK-NOT: call void @llvm.lifetime.start(
+; CHECK: call i32 @callee2(i8* [[ALLOCA]])
+; CHECK-NOT: call void @llvm.lifetime.end(
+
+define i32 @caller1(i32 %count) {
+  %call0 = call i32 @callee1(i32 0)
+  ret i32 %call0
+}