[GMR/OperandBundles] Teach getModRefBehavior about operand bundles

In general, memory restrictions on a called function (e.g. readnone)
cannot be transferred to a CallSite that has operand bundles.  It is
possible to make this inference smarter, but lets fix the behavior to be
correct first.

llvm-svn: 260193

1 files changed, 27 insertions, 0 deletions

diff --git a/llvm/test/Feature/OperandBundles/pr26510.ll b/llvm/test/Feature/OperandBundles/pr26510.ll
new file mode 100644
index 00000000000..d1d60b47313
--- /dev/null
+++ b/llvm/test/Feature/OperandBundles/pr26510.ll
@@ -0,0 +1,27 @@
+; RUN: opt -S -globals-aa -functionattrs < %s | FileCheck %s
+; RUN: opt -S -O3 < %s | FileCheck %s
+
+; Apart from checking for the direct cause of the bug, we also check
+; if any problematic aliasing rules have accidentally snuck into -O3.
+;
+; Since the "abc" operand bundle is not a special operand bundle that
+; LLVM knows about, all of the stores and loads in @test below have to
+; stay.
+
+declare void @foo() readnone
+
+; CHECK-LABEL: define i8* @test(i8* %p) {
+; CHECK:   %a = alloca i8*, align 8
+; CHECK:   store i8* %p, i8** %a, align 8
+; CHECK:   call void @foo() [ "abc"(i8** %a) ]
+; CHECK:   %reload = load i8*, i8** %a, align 8
+; CHECK:   ret i8* %reload
+; CHECK: }
+
+define i8* @test(i8* %p) {
+  %a = alloca i8*, align 8
+  store i8* %p, i8** %a, align 8
+  call void @foo() ["abc" (i8** %a)]
+  %reload = load i8*, i8** %a, align 8
+  ret i8* %reload
+}