[PATCH] D12932: [LazyValueInfo] Report nonnull range for nonnull pointers

[Igor Laevsky via llvm-commits]

igor-laevsky created this revision.
igor-laevsky added a reviewer: reames.
igor-laevsky added a subscriber: llvm-commits.
igor-laevsky set the repository for this revision to rL LLVM.

Currently LazyValueInfo will report only alloca's as having nonnull range. For loads with !nonnull metadata it will bailout with no additional information. Same is true for calls returning nonnull pointers.

This change extends LazyValueInfo to handle this additional nonnull instructions.



Repository:
  rL LLVM

http://reviews.llvm.org/D12932

Files:
  lib/Analysis/LazyValueInfo.cpp
  test/Transforms/CorrelatedValuePropagation/non-null.ll

Index: test/Transforms/CorrelatedValuePropagation/non-null.ll
===================================================================
--- test/Transforms/CorrelatedValuePropagation/non-null.ll
+++ test/Transforms/CorrelatedValuePropagation/non-null.ll
@@ -140,3 +140,24 @@
   ; CHECK: call void @test11_helper(i8* nonnull %merged_arg)
   ret void
 }
+
+declare void @test12_helper(i8* %arg)
+define void @test12(i8* %arg1, i8** %arg2) {
+; CHECK-LABEL: @test12
+entry:
+  %is_null = icmp eq i8* %arg1, null
+  br i1 %is_null, label %null, label %non_null
+
+non_null:
+  br label %merge
+
+null:
+  %another_arg = load i8*, i8** %arg2, !nonnull !{}
+  br label %merge
+
+merge:
+  %merged_arg = phi i8* [%another_arg, %null], [%arg1, %non_null]
+  call void @test12_helper(i8* %merged_arg)
+  ; CHECK: call void @test12_helper(i8* nonnull %merged_arg)
+  ret void
+}
Index: lib/Analysis/LazyValueInfo.cpp
===================================================================
--- lib/Analysis/LazyValueInfo.cpp
+++ lib/Analysis/LazyValueInfo.cpp
@@ -531,8 +531,11 @@
     return true;
   }
 
-  if (AllocaInst *AI = dyn_cast<AllocaInst>(BBI)) {
-    Res = LVILatticeVal::getNot(ConstantPointerNull::get(AI->getType()));
+  // If this value is a nonnull pointer, record it's range and bailout.
+  if (BBI->getType()->isPointerTy() &&
+      isKnownNonNull(BBI)) {
+    Res = LVILatticeVal::getNot(
+        ConstantPointerNull::get(cast<PointerType>(BBI->getType())));
     insertResult(Val, BB, Res);
     return true;
   }


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