Change the default attributes for llvm.prefetch to inaccessiblemem_or_argmemonly

so that we can perform some optimizations across it.

Fixes PR32365

llvm-svn: 298781

8 files changed, 65 insertions, 25 deletions

diff --git a/llvm/include/llvm/IR/Intrinsics.td b/llvm/include/llvm/IR/Intrinsics.td
index c0305a08d1b..c1a36f1ed48 100644
--- a/llvm/include/llvm/IR/Intrinsics.td
+++ b/llvm/include/llvm/IR/Intrinsics.td
@@ -331,13 +331,13 @@ def int_get_dynamic_area_offset : Intrinsic<[llvm_anyint_ty]>;
 def int_thread_pointer : Intrinsic<[llvm_ptr_ty], [], [IntrNoMem]>,
                          GCCBuiltin<"__builtin_thread_pointer">;
 
-// IntrArgMemOnly is more pessimistic than strictly necessary for prefetch,
-// however it does conveniently prevent the prefetch from being reordered
-// with respect to nearby accesses to the same memory.
-def int_prefetch      : Intrinsic<[],
-                                  [llvm_ptr_ty, llvm_i32_ty, llvm_i32_ty,
-                                   llvm_i32_ty],
-                                  [IntrArgMemOnly, NoCapture<0>]>;
+// IntrInaccessibleMemOrArgMemOnly is a little more pessimistic than strictly
+// necessary for prefetch, however it does conveniently prevent the prefetch
+// from being reordered overly much with respect to nearby access to the same
+// memory while not impeding optimization.
+def int_prefetch
+    : Intrinsic<[], [ llvm_ptr_ty, llvm_i32_ty, llvm_i32_ty, llvm_i32_ty ],
+                [ IntrInaccessibleMemOrArgMemOnly, ReadOnly<0>, NoCapture<0> ]>;
 def int_pcmarker      : Intrinsic<[], [llvm_i32_ty]>;
 
 def int_readcyclecounter : Intrinsic<[llvm_i64_ty]>;
diff --git a/llvm/test/Bitcode/compatibility-3.6.ll b/llvm/test/Bitcode/compatibility-3.6.ll
index 87958fc3418..8d51ee11a20 100644
--- a/llvm/test/Bitcode/compatibility-3.6.ll
+++ b/llvm/test/Bitcode/compatibility-3.6.ll
@@ -981,7 +981,7 @@ exit:
   ; CHECK: select <2 x i1> <i1 true, i1 false>, <2 x i8> <i8 2, i8 3>, <2 x i8> <i8 3, i8 2>
 
   call void @f.nobuiltin() builtin
-  ; CHECK: call void @f.nobuiltin() #33
+  ; CHECK: call void @f.nobuiltin() #34
 
   call fastcc noalias i32* @f.noalias() noinline
   ; CHECK: call fastcc noalias i32* @f.noalias() #11
@@ -1183,7 +1183,8 @@ define void @intrinsics.codegen() {
 ; CHECK: attributes #30 = { argmemonly nounwind readonly }
 ; CHECK: attributes #31 = { argmemonly nounwind }
 ; CHECK: attributes #32 = { nounwind readonly }
-; CHECK: attributes #33 = { builtin }
+; CHECK: attributes #33 = { inaccessiblemem_or_argmemonly nounwind }
+; CHECK: attributes #34 = { builtin }
 
 ;; Metadata
 
diff --git a/llvm/test/Bitcode/compatibility-3.7.ll b/llvm/test/Bitcode/compatibility-3.7.ll
index 4ae0aed2018..ebdf4c30587 100644
--- a/llvm/test/Bitcode/compatibility-3.7.ll
+++ b/llvm/test/Bitcode/compatibility-3.7.ll
@@ -1022,7 +1022,7 @@ exit:
   ; CHECK: select <2 x i1> <i1 true, i1 false>, <2 x i8> <i8 2, i8 3>, <2 x i8> <i8 3, i8 2>
 
   call void @f.nobuiltin() builtin
-  ; CHECK: call void @f.nobuiltin() #36
+  ; CHECK: call void @f.nobuiltin() #37
 
   call fastcc noalias i32* @f.noalias() noinline
   ; CHECK: call fastcc noalias i32* @f.noalias() #12
@@ -1246,7 +1246,8 @@ define void @misc.metadata() {
 ; CHECK: attributes #33 = { argmemonly nounwind readonly }
 ; CHECK: attributes #34 = { argmemonly nounwind }
 ; CHECK: attributes #35 = { nounwind readonly }
-; CHECK: attributes #36 = { builtin }
+; CHECK: attributes #36 = { inaccessiblemem_or_argmemonly nounwind }
+; CHECK: attributes #37 = { builtin }
 
 ;; Metadata
 
diff --git a/llvm/test/Bitcode/compatibility-3.8.ll b/llvm/test/Bitcode/compatibility-3.8.ll
index 79c1ecfac9f..57ea3e06837 100644
--- a/llvm/test/Bitcode/compatibility-3.8.ll
+++ b/llvm/test/Bitcode/compatibility-3.8.ll
@@ -1170,7 +1170,7 @@ exit:
   ; CHECK: select <2 x i1> <i1 true, i1 false>, <2 x i8> <i8 2, i8 3>, <2 x i8> <i8 3, i8 2>
 
   call void @f.nobuiltin() builtin
-  ; CHECK: call void @f.nobuiltin() #39
+  ; CHECK: call void @f.nobuiltin() #40
 
   call fastcc noalias i32* @f.noalias() noinline
   ; CHECK: call fastcc noalias i32* @f.noalias() #12
@@ -1556,7 +1556,8 @@ normal:
 ; CHECK: attributes #36 = { argmemonly nounwind readonly }
 ; CHECK: attributes #37 = { argmemonly nounwind }
 ; CHECK: attributes #38 = { nounwind readonly }
-; CHECK: attributes #39 = { builtin }
+; CHECK: attributes #39 = { inaccessiblemem_or_argmemonly nounwind }
+; CHECK: attributes #40 = { builtin }
 
 ;; Metadata
 
diff --git a/llvm/test/Bitcode/compatibility-3.9.ll b/llvm/test/Bitcode/compatibility-3.9.ll
index 300be3324e6..2a6cfe14cdb 100644
--- a/llvm/test/Bitcode/compatibility-3.9.ll
+++ b/llvm/test/Bitcode/compatibility-3.9.ll
@@ -1241,7 +1241,7 @@ exit:
   ; CHECK: select <2 x i1> <i1 true, i1 false>, <2 x i8> <i8 2, i8 3>, <2 x i8> <i8 3, i8 2>
 
   call void @f.nobuiltin() builtin
-  ; CHECK: call void @f.nobuiltin() #40
+  ; CHECK: call void @f.nobuiltin() #41
 
   call fastcc noalias i32* @f.noalias() noinline
   ; CHECK: call fastcc noalias i32* @f.noalias() #12
@@ -1588,7 +1588,7 @@ normal:
 }
 
 declare void @f.writeonly() writeonly
-; CHECK: declare void @f.writeonly() #39
+; CHECK: declare void @f.writeonly() #40
 
 ; CHECK: attributes #0 = { alignstack=4 }
 ; CHECK: attributes #1 = { alignstack=8 }
@@ -1629,8 +1629,9 @@ declare void @f.writeonly() writeonly
 ; CHECK: attributes #36 = { argmemonly nounwind readonly }
 ; CHECK: attributes #37 = { argmemonly nounwind }
 ; CHECK: attributes #38 = { nounwind readonly }
-; CHECK: attributes #39 = { writeonly }
-; CHECK: attributes #40 = { builtin }
+; CHECK: attributes #39 = { inaccessiblemem_or_argmemonly nounwind }
+; CHECK: attributes #40 = { writeonly }
+; CHECK: attributes #41 = { builtin }
 
 ;; Metadata
 
diff --git a/llvm/test/Bitcode/compatibility-4.0.ll b/llvm/test/Bitcode/compatibility-4.0.ll
index fa7a9b1e1e0..c83c107a292 100644
--- a/llvm/test/Bitcode/compatibility-4.0.ll
+++ b/llvm/test/Bitcode/compatibility-4.0.ll
@@ -1241,7 +1241,7 @@ exit:
   ; CHECK: select <2 x i1> <i1 true, i1 false>, <2 x i8> <i8 2, i8 3>, <2 x i8> <i8 3, i8 2>
 
   call void @f.nobuiltin() builtin
-  ; CHECK: call void @f.nobuiltin() #40
+  ; CHECK: call void @f.nobuiltin() #41
 
   call fastcc noalias i32* @f.noalias() noinline
   ; CHECK: call fastcc noalias i32* @f.noalias() #12
@@ -1606,7 +1606,7 @@ normal:
 
 
 declare void @f.writeonly() writeonly
-; CHECK: declare void @f.writeonly() #39
+; CHECK: declare void @f.writeonly() #40
 
 ;; Constant Expressions
 
@@ -1654,8 +1654,9 @@ define i8** @constexpr() {
 ; CHECK: attributes #36 = { argmemonly nounwind readonly }
 ; CHECK: attributes #37 = { argmemonly nounwind }
 ; CHECK: attributes #38 = { nounwind readonly }
-; CHECK: attributes #39 = { writeonly }
-; CHECK: attributes #40 = { builtin }
+; CHECK: attributes #39 = { inaccessiblemem_or_argmemonly nounwind }
+; CHECK: attributes #40 = { writeonly }
+; CHECK: attributes #41 = { builtin }
 
 ;; Metadata
 
diff --git a/llvm/test/Bitcode/compatibility.ll b/llvm/test/Bitcode/compatibility.ll
index e2b13f47d3b..f1a883e53ad 100644
--- a/llvm/test/Bitcode/compatibility.ll
+++ b/llvm/test/Bitcode/compatibility.ll
@@ -1244,7 +1244,7 @@ exit:
   ; CHECK: select <2 x i1> <i1 true, i1 false>, <2 x i8> <i8 2, i8 3>, <2 x i8> <i8 3, i8 2>
 
   call void @f.nobuiltin() builtin
-  ; CHECK: call void @f.nobuiltin() #40
+  ; CHECK: call void @f.nobuiltin() #41
 
   call fastcc noalias i32* @f.noalias() noinline
   ; CHECK: call fastcc noalias i32* @f.noalias() #12
@@ -1609,7 +1609,7 @@ normal:
 
 
 declare void @f.writeonly() writeonly
-; CHECK: declare void @f.writeonly() #39
+; CHECK: declare void @f.writeonly() #40
 
 ;; Constant Expressions
 
@@ -1657,8 +1657,9 @@ define i8** @constexpr() {
 ; CHECK: attributes #36 = { argmemonly nounwind readonly }
 ; CHECK: attributes #37 = { argmemonly nounwind }
 ; CHECK: attributes #38 = { nounwind readonly }
-; CHECK: attributes #39 = { writeonly }
-; CHECK: attributes #40 = { builtin }
+; CHECK: attributes #39 = { inaccessiblemem_or_argmemonly nounwind }
+; CHECK: attributes #40 = { writeonly }
+; CHECK: attributes #41 = { builtin }
 
 ;; Metadata
 
diff --git a/llvm/test/Transforms/InstCombine/prefetch-load.ll b/llvm/test/Transforms/InstCombine/prefetch-load.ll
new file mode 100644
index 00000000000..f98b7ae00bf
--- /dev/null
+++ b/llvm/test/Transforms/InstCombine/prefetch-load.ll
@@ -0,0 +1,34 @@
+; RUN: opt < %s -instcombine -S | FileCheck %s
+
+%struct.C = type { %struct.C*, i32 }
+
+; Check that we instcombine the load across the prefetch.
+
+; CHECK-LABEL: define signext i32 @foo
+define signext i32 @foo(%struct.C* %c) local_unnamed_addr #0 {
+; CHECK: store i32 %dec, i32* %length_
+; CHECK-NOT: load
+; CHECK: llvm.prefetch
+; CHECK-NEXT: ret
+entry:
+  %next_ = getelementptr inbounds %struct.C, %struct.C* %c, i32 0, i32 0
+  %0 = load %struct.C*, %struct.C** %next_, align 8
+  %next_1 = getelementptr inbounds %struct.C, %struct.C* %0, i32 0, i32 0
+  %1 = load %struct.C*, %struct.C** %next_1, align 8
+  store %struct.C* %1, %struct.C** %next_, align 8
+  %length_ = getelementptr inbounds %struct.C, %struct.C* %c, i32 0, i32 1
+  %2 = load i32, i32* %length_, align 8
+  %dec = add nsw i32 %2, -1
+  store i32 %dec, i32* %length_, align 8
+  %3 = bitcast %struct.C* %1 to i8*
+  call void @llvm.prefetch(i8* %3, i32 0, i32 0, i32 1)
+  %4 = load i32, i32* %length_, align 8
+  ret i32 %4
+}
+
+; Function Attrs: inaccessiblemem_or_argmemonly nounwind
+declare void @llvm.prefetch(i8* nocapture readonly, i32, i32, i32) 
+
+attributes #0 = { noinline nounwind }
+; We've explicitly removed the function attrs from llvm.prefetch so we get the defaults.
+; attributes #1 = { inaccessiblemem_or_argmemonly nounwind }