[llvm-commits] [llvm] r118439 - /llvm/trunk/test/Analysis/TypeBasedAliasAnalysis/functionattrs.ll

[Dan Gohman]

Author: djg
Date: Mon Nov  8 14:20:11 2010
New Revision: 118439

URL: http://llvm.org/viewvc/llvm-project?rev=118439&view=rev
Log:
Add a testcase for a call which BasicAA says only accesses memory through
its arguments and which TBAA says doesn't write to memory.

Modified:
    llvm/trunk/test/Analysis/TypeBasedAliasAnalysis/functionattrs.ll

Modified: llvm/trunk/test/Analysis/TypeBasedAliasAnalysis/functionattrs.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Analysis/TypeBasedAliasAnalysis/functionattrs.ll?rev=118439&r1=118438&r2=118439&view=diff
==============================================================================
--- llvm/trunk/test/Analysis/TypeBasedAliasAnalysis/functionattrs.ll (original)
+++ llvm/trunk/test/Analysis/TypeBasedAliasAnalysis/functionattrs.ll Mon Nov  8 14:20:11 2010
@@ -2,6 +2,13 @@
 
 ; FunctionAttrs should make use of TBAA.
 
+; Add the readnone attribute, since the only access is a store which TBAA
+; says is to constant memory.
+;
+; It's unusual to see a store to constant memory, but it isn't necessarily
+; invalid, as it's possible that this only happens after optimization on a
+; code path which isn't ever executed.
+
 ; CHECK: define void @test0_yes(i32* nocapture %p) nounwind readnone {
 define void @test0_yes(i32* %p) nounwind {
   store i32 0, i32* %p, !tbaa !1
@@ -14,6 +21,9 @@
   ret void
 }
 
+; Add the readonly attribute, since there's just a call to a function which 
+; TBAA says doesn't modify any memory.
+
 ; CHECK: define void @test1_yes(i32* %p) nounwind readonly {
 define void @test1_yes(i32* %p) nounwind {
   call void @callee(i32* %p), !tbaa !1
@@ -26,7 +36,27 @@
   ret void
 }
 
+; Add the readonly attribute, as above, but this time BasicAA will say
+; that the function accesses memory through its arguments, which TBAA
+; still says that the function doesn't write to memory.
+;
+; This is unusual, since the function is memcpy, but as above, this
+; isn't necessarily invalid.
+
+; CHECK: define void @test2_yes(i8* nocapture %p, i8* nocapture %q, i64 %n) nounwind readnone {
+define void @test2_yes(i8* %p, i8* %q, i64 %n) nounwind {
+  call void @llvm.memcpy.p0i8.p0i8.i64(i8* %p, i8* %q, i64 %n, i32 1, i1 false), !tbaa !1
+  ret void
+}
+
+; CHECK: define void @test2_no(i8* nocapture %p, i8* nocapture %q, i64 %n) nounwind {
+define void @test2_no(i8* %p, i8* %q, i64 %n) nounwind {
+  call void @llvm.memcpy.p0i8.p0i8.i64(i8* %p, i8* %q, i64 %n, i32 1, i1 false), !tbaa !2
+  ret void
+}
+
 declare void @callee(i32* %p) nounwind
+declare void @llvm.memcpy.p0i8.p0i8.i64(i8*, i8*, i64, i32, i1) nounwind
 
 ; Root note.
 !0 = metadata !{ }