[AliasAnalysis] Take into account readnone attribute for the function arguments

Differential Revision: http://reviews.llvm.org/D13992

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@251535 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Analysis/BasicAliasAnalysis.cpp b/lib/Analysis/BasicAliasAnalysis.cpp
index 26578b83c8b114490f3325f4edef4edd8a6fcf02..1f7e82d315828cf755d31049ddb6ee2306bc7544 100644 (file)
--- a/lib/Analysis/BasicAliasAnalysis.cpp
+++ b/lib/Analysis/BasicAliasAnalysis.cpp
@@ -619,6 +619,9 @@ ModRefInfo BasicAAResult::getArgModRefInfo(ImmutableCallSite CS,
   if (CS.paramHasAttr(ArgIdx + 1, Attribute::ReadOnly))
     return MRI_Ref;
 
   if (CS.paramHasAttr(ArgIdx + 1, Attribute::ReadOnly))
     return MRI_Ref;
 

+  if (CS.paramHasAttr(ArgIdx + 1, Attribute::ReadNone))
+    return MRI_NoModRef;
+

   return AAResultBase::getArgModRefInfo(CS, ArgIdx);
 }
 
   return AAResultBase::getArgModRefInfo(CS, ArgIdx);
 }
 

diff --git a/test/Analysis/BasicAA/modref.ll b/test/Analysis/BasicAA/modref.ll
index 342d3fc23cdc59175fdbf7a040105fcfeda5f2ea..e42793936c3dcffa8edf718312c71195f0f33761 100644 (file)
--- a/test/Analysis/BasicAA/modref.ll
+++ b/test/Analysis/BasicAA/modref.ll
@@ -216,6 +216,17 @@ define i32 @test12(i32* %P, i32* %P2, i32* %P3) {
   ; CHECK: ret i32 %Diff
 }
 
   ; CHECK: ret i32 %Diff
 }
 

+; CHECK-LABEL: @test13(
+define i32 @test13(i32* %P, i32* %P2) {
+  %V1 = load i32, i32* %P
+  call i32 @func_argmemonly(i32* readnone %P2)
+  %V2 = load i32, i32* %P
+  %Diff = sub i32 %V1, %V2
+  ret i32 %Diff
+  ; CHECK-NOT: load
+  ; CHECK: ret i32 0
+}
+

 declare void @llvm.memset.p0i8.i32(i8* nocapture, i8, i32, i32, i1) nounwind
 declare void @llvm.memset.p0i8.i8(i8* nocapture, i8, i8, i32, i1) nounwind
 declare void @llvm.memcpy.p0i8.p0i8.i8(i8* nocapture, i8* nocapture, i8, i32, i1) nounwind
 declare void @llvm.memset.p0i8.i32(i8* nocapture, i8, i32, i32, i1) nounwind
 declare void @llvm.memset.p0i8.i8(i8* nocapture, i8, i8, i32, i1) nounwind
 declare void @llvm.memcpy.p0i8.p0i8.i8(i8* nocapture, i8* nocapture, i8, i32, i1) nounwind