[PATCH] D9384: llvm.noalias - isPointerDereferenceable should look through them

[Hal Finkel via llvm-commits]

hfinkel updated this revision to Diff 63351.
hfinkel added a comment.
Herald added a subscriber: mcrosier.

Rebased.


http://reviews.llvm.org/D9384

Files:
  lib/Analysis/Loads.cpp
  test/Analysis/ValueTracking/memory-dereferenceable.ll

Index: test/Analysis/ValueTracking/memory-dereferenceable.ll
===================================================================
--- test/Analysis/ValueTracking/memory-dereferenceable.ll
+++ test/Analysis/ValueTracking/memory-dereferenceable.ll
@@ -43,7 +43,8 @@
     %load4 = load i32, i32 addrspace(1)* %relocate
 
 ; CHECK-NOT: %nparam
-    %nparam = getelementptr i32, i32 addrspace(1)* %dparam, i32 5
+    %dpa = call i32 addrspace(1)* @llvm.noalias.p1i32(i32 addrspace(1)* %dparam, metadata !4)
+    %nparam = getelementptr i32, i32 addrspace(1)* %dpa, i32 5
     %load5 = load i32, i32 addrspace(1)* %nparam
 
     ; Load from a non-dereferenceable load
@@ -162,6 +163,12 @@
 declare token @llvm.experimental.gc.statepoint.p0f_i1f(i64, i32, i1 ()*, i32, i32, ...)
 declare i32 addrspace(1)* @llvm.experimental.gc.relocate.p1i32(token, i32, i32)
 
+declare i32 addrspace(1)* @llvm.noalias.p1i32(i32 addrspace(1)*, metadata) nounwind argmemonly
+
 !0 = !{i64 4}
 !1 = !{i64 2}
 !2 = !{}
+
+!3 = !{!3, !"some domain"}
+!4 = !{!4, !3, !"some scope"}
+
Index: lib/Analysis/Loads.cpp
===================================================================
--- lib/Analysis/Loads.cpp
+++ lib/Analysis/Loads.cpp
@@ -101,6 +101,11 @@
     return isDereferenceableAndAlignedPointer(ASC->getOperand(0), Align, Size,
                                               DL, CtxI, DT, Visited);
 
+  if (const IntrinsicInst *I = dyn_cast<IntrinsicInst>(V))
+    if (I->getIntrinsicID() == Intrinsic::noalias)
+      return isDereferenceableAndAlignedPointer(I->getOperand(0), Align, Size,
+                                                DL, CtxI, DT, Visited);
+
   // If we don't know, assume the worst.
   return false;
 }


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