[NVPTX] Disable relative lookup tables (#159748)

Relative lookup tables result in "LLVM ERROR: Circular dependency found
in global variable set", so disable them for this target.

(cherry picked from commit 1ed1537)

Author: nikic

llvm/lib/Target/NVPTX/NVPTXTargetTransformInfo.h

@@ -183,6 +183,11 @@ class NVPTXTTIImpl final : public BasicTTIImplBase<NVPTXTTIImpl> {
   void collectKernelLaunchBounds(
       const Function &F,
       SmallVectorImpl<std::pair<StringRef, int64_t>> &LB) const override;
+
+  bool shouldBuildRelLookupTables() const override {
+    // Self-referential globals are not supported.
+    return false;
+  }
 };
 
 } // end namespace llvm

llvm/test/Transforms/RelLookupTableConverter/nvptx.ll

@@ -0,0 +1,32 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --check-globals all --version 5
+; RUN: opt < %s -passes=rel-lookup-table-converter -relocation-model=pic -S | FileCheck %s
+; REQUIRES: nvptx-registered-target
+target triple = "nvptx64-nvidia-cuda"
+
+; Do not produce relative lookup table for nvptx target.
+
+@a1 = internal constant i32 0, align 4
+@b1 = internal constant i32 0, align 4
+@c1 = internal constant i32 0, align 4
+@d1 = internal constant i32 0, align 4
+
+@switch.table = private unnamed_addr constant [3 x ptr] [ptr @a1, ptr @b1, ptr @c1], align 8
+
+;.
+; CHECK: @a1 = internal constant i32 0, align 4
+; CHECK: @b1 = internal constant i32 0, align 4
+; CHECK: @c1 = internal constant i32 0, align 4
+; CHECK: @d1 = internal constant i32 0, align 4
+; CHECK: @switch.table = private unnamed_addr constant [3 x ptr] [ptr @a1, ptr @b1, ptr @c1], align 8
+;.
+define ptr @internal_linkage(i32 %cond) {
+; CHECK-LABEL: define ptr @internal_linkage(
+; CHECK-SAME: i32 [[COND:%.*]]) {
+; CHECK-NEXT:    [[SWITCH_GEP:%.*]] = getelementptr inbounds [3 x ptr], ptr @switch.table, i32 0, i32 [[COND]]
+; CHECK-NEXT:    [[RELTABLE_INTRINSIC:%.*]] = load ptr, ptr [[SWITCH_GEP]], align 8
+; CHECK-NEXT:    ret ptr [[RELTABLE_INTRINSIC]]
+;
+  %switch.gep = getelementptr inbounds [3 x ptr], ptr @switch.table, i32 0, i32 %cond
+  %switch.load = load ptr, ptr %switch.gep, align 8
+  ret ptr %switch.load
+}