Look through addrspacecast when checking isDereferenceablePointer

llvm-svn: 212971

2 files changed, 41 insertions, 0 deletions

diff --git a/llvm/lib/IR/Value.cpp b/llvm/lib/IR/Value.cpp
index 35c241a608b..999685e15eb 100644
--- a/llvm/lib/IR/Value.cpp
+++ b/llvm/lib/IR/Value.cpp
@@ -543,6 +543,9 @@ static bool isDereferenceablePointer(const Value *V, const DataLayout *DL,
     return true;
   }
 
+  if (const AddrSpaceCastInst *ASC = dyn_cast<AddrSpaceCastInst>(V))
+    return isDereferenceablePointer(ASC->getOperand(0), DL, Visited);
+
   // If we don't know, assume the worst.
   return false;
 }
diff --git a/llvm/test/Transforms/LICM/hoist-bitcast-load.ll b/llvm/test/Transforms/LICM/hoist-bitcast-load.ll
index 639dca5f17e..fa61eaf5b46 100644
--- a/llvm/test/Transforms/LICM/hoist-bitcast-load.ll
+++ b/llvm/test/Transforms/LICM/hoist-bitcast-load.ll
@@ -78,6 +78,44 @@ for.end:                                          ; preds = %for.inc, %entry
   ret void
 }
 
+; Make sure the basic alloca pointer hoisting works through an addrspacecast
+; CHECK-LABEL: @test2_addrspacecast
+; CHECK: load i32 addrspace(1)* %c, align 4
+; CHECK: for.body:
+
+; Function Attrs: nounwind uwtable
+define void @test2_addrspacecast(i32 addrspace(1)* nocapture %a, i32 addrspace(1)* nocapture readonly %b, i32 %n) #0 {
+entry:
+  %cmp6 = icmp sgt i32 %n, 0
+  %ca = alloca i64
+  %c = addrspacecast i64* %ca to i32 addrspace(1)*
+  br i1 %cmp6, label %for.body, label %for.end
+
+for.body:                                         ; preds = %entry, %for.inc
+  %indvars.iv = phi i64 [ %indvars.iv.next, %for.inc ], [ 0, %entry ]
+  %arrayidx = getelementptr inbounds i32 addrspace(1)* %a, i64 %indvars.iv
+  %0 = load i32 addrspace(1)* %arrayidx, align 4
+  %cmp1 = icmp sgt i32 %0, 0
+  br i1 %cmp1, label %if.then, label %for.inc
+
+if.then:                                          ; preds = %for.body
+  %1 = load i32 addrspace(1)* %c, align 4
+  %arrayidx3 = getelementptr inbounds i32 addrspace(1)* %b, i64 %indvars.iv
+  %2 = load i32 addrspace(1)* %arrayidx3, align 4
+  %mul = mul nsw i32 %2, %1
+  store i32 %mul, i32 addrspace(1)* %arrayidx, align 4
+  br label %for.inc
+
+for.inc:                                          ; preds = %for.body, %if.then
+  %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
+  %lftr.wideiv = trunc i64 %indvars.iv.next to i32
+  %exitcond = icmp eq i32 %lftr.wideiv, %n
+  br i1 %exitcond, label %for.end, label %for.body
+
+for.end:                                          ; preds = %for.inc, %entry
+  ret void
+}
+
 ; Make sure the basic alloca pointer hoisting works through a bitcast to a
 ; pointer to a smaller type (where the bitcast also needs to be hoisted):
 ; CHECK-LABEL: @test3