AMDGPU: Add instruction flags when lowering ctor/dtor (#111652)

These should be well behaved address computations.

Author: arsenm

llvm/lib/Target/AMDGPU/AMDGPUCtorDtorLowering.cpp

@@ -112,9 +112,13 @@ static void createInitOrFiniCalls(Function &F, bool IsCtor) {
     Type *Int64Ty = IntegerType::getInt64Ty(C);
     auto *EndPtr = IRB.CreatePtrToInt(End, Int64Ty);
     auto *BeginPtr = IRB.CreatePtrToInt(Begin, Int64Ty);
-    auto *ByteSize = IRB.CreateSub(EndPtr, BeginPtr);
-    auto *Size = IRB.CreateAShr(ByteSize, ConstantInt::get(Int64Ty, 3));
-    auto *Offset = IRB.CreateSub(Size, ConstantInt::get(Int64Ty, 1));
+    auto *ByteSize = IRB.CreateSub(EndPtr, BeginPtr, "", /*HasNUW=*/true,
+                                   /*HasNSW=*/true);
+    auto *Size = IRB.CreateAShr(ByteSize, ConstantInt::get(Int64Ty, 3), "",
+                                /*isExact=*/true);
+    auto *Offset =
+        IRB.CreateSub(Size, ConstantInt::get(Int64Ty, 1), "", /*HasNUW=*/true,
+                      /*HasNSW=*/true);
     Start = IRB.CreateInBoundsGEP(
         PtrArrayTy, Begin,
         ArrayRef<Value *>({ConstantInt::get(Int64Ty, 0), Offset}));

llvm/test/CodeGen/AMDGPU/lower-ctor-dtor-constexpr-alias.ll

@@ -64,8 +64,8 @@ define void @bar() addrspace(1) {
 ; CHECK-LABEL: define weak_odr amdgpu_kernel void @amdgcn.device.fini(
 ; CHECK-SAME: ) #[[ATTR2:[0-9]+]] {
 ; CHECK-NEXT:  entry:
-; CHECK-NEXT:    [[TMP0:%.*]] = ashr i64 sub (i64 ptrtoint (ptr addrspace(1) @__fini_array_end to i64), i64 ptrtoint (ptr addrspace(1) @__fini_array_start to i64)), 3
-; CHECK-NEXT:    [[TMP1:%.*]] = sub i64 [[TMP0]], 1
+; CHECK-NEXT:    [[TMP0:%.*]] = ashr exact i64 sub nuw nsw (i64 ptrtoint (ptr addrspace(1) @__fini_array_end to i64), i64 ptrtoint (ptr addrspace(1) @__fini_array_start to i64)), 3
+; CHECK-NEXT:    [[TMP1:%.*]] = sub nuw nsw i64 [[TMP0]], 1
 ; CHECK-NEXT:    [[TMP2:%.*]] = getelementptr inbounds [0 x ptr addrspace(1)], ptr addrspace(1) @__fini_array_start, i64 0, i64 [[TMP1]]
 ; CHECK-NEXT:    [[TMP3:%.*]] = icmp uge ptr addrspace(1) [[TMP2]], @__fini_array_start
 ; CHECK-NEXT:    br i1 [[TMP3]], label [[WHILE_ENTRY:%.*]], label [[WHILE_END:%.*]]

llvm/test/CodeGen/AMDGPU/lower-ctor-dtor.ll

@@ -79,8 +79,8 @@ define internal void @bar() {
 ; CHECK-LABEL: define weak_odr amdgpu_kernel void @amdgcn.device.fini(
 ; CHECK-SAME: ) #[[ATTR1:[0-9]+]] {
 ; CHECK-NEXT:  entry:
-; CHECK-NEXT:    [[TMP0:%.*]] = ashr i64 sub (i64 ptrtoint (ptr addrspace(1) @__fini_array_end to i64), i64 ptrtoint (ptr addrspace(1) @__fini_array_start to i64)), 3
-; CHECK-NEXT:    [[TMP1:%.*]] = sub i64 [[TMP0]], 1
+; CHECK-NEXT:    [[TMP0:%.*]] = ashr exact i64 sub nuw nsw (i64 ptrtoint (ptr addrspace(1) @__fini_array_end to i64), i64 ptrtoint (ptr addrspace(1) @__fini_array_start to i64)), 3
+; CHECK-NEXT:    [[TMP1:%.*]] = sub nuw nsw i64 [[TMP0]], 1
 ; CHECK-NEXT:    [[TMP2:%.*]] = getelementptr inbounds [0 x ptr addrspace(1)], ptr addrspace(1) @__fini_array_start, i64 0, i64 [[TMP1]]
 ; CHECK-NEXT:    [[TMP3:%.*]] = icmp uge ptr addrspace(1) [[TMP2]], @__fini_array_start
 ; CHECK-NEXT:    br i1 [[TMP3]], label [[WHILE_ENTRY:%.*]], label [[WHILE_END:%.*]]

llvm/test/CodeGen/AMDGPU/lower-multiple-ctor-dtor.ll

@@ -71,8 +71,8 @@ define internal void @bar.5() {
 ; CHECK-LABEL: define weak_odr amdgpu_kernel void @amdgcn.device.fini(
 ; CHECK-SAME: ) #[[ATTR1:[0-9]+]] {
 ; CHECK-NEXT:  entry:
-; CHECK-NEXT:    [[TMP0:%.*]] = ashr i64 sub (i64 ptrtoint (ptr addrspace(1) @__fini_array_end to i64), i64 ptrtoint (ptr addrspace(1) @__fini_array_start to i64)), 3
-; CHECK-NEXT:    [[TMP1:%.*]] = sub i64 [[TMP0]], 1
+; CHECK-NEXT:    [[TMP0:%.*]] = ashr exact i64 sub nuw nsw (i64 ptrtoint (ptr addrspace(1) @__fini_array_end to i64), i64 ptrtoint (ptr addrspace(1) @__fini_array_start to i64)), 3
+; CHECK-NEXT:    [[TMP1:%.*]] = sub nuw nsw i64 [[TMP0]], 1
 ; CHECK-NEXT:    [[TMP2:%.*]] = getelementptr inbounds [0 x ptr addrspace(1)], ptr addrspace(1) @__fini_array_start, i64 0, i64 [[TMP1]]
 ; CHECK-NEXT:    [[TMP3:%.*]] = icmp uge ptr addrspace(1) [[TMP2]], @__fini_array_start
 ; CHECK-NEXT:    br i1 [[TMP3]], label [[WHILE_ENTRY:%.*]], label [[WHILE_END:%.*]]