[llvm] InferAddressSpaces: Handle prefetch intrinsic (PR #101982)

[Matt Arsenault via llvm-commits]

https://github.com/arsenm updated https://github.com/llvm/llvm-project/pull/101982

>From 2df6107ca023eb707c0def98b0ec2d10b6a985b5 Mon Sep 17 00:00:00 2001
From: Matt Arsenault <Matthew.Arsenault at amd.com>
Date: Mon, 5 Aug 2024 11:25:58 +0400
Subject: [PATCH] InferAddressSpaces: Handle prefetch intrinsic

---
 .../Transforms/Scalar/InferAddressSpaces.cpp  |  8 +++
 .../InferAddressSpaces/AMDGPU/prefetch.ll     | 59 +++++++++++++++++++
 2 files changed, 67 insertions(+)
 create mode 100644 llvm/test/Transforms/InferAddressSpaces/AMDGPU/prefetch.ll

diff --git a/llvm/lib/Transforms/Scalar/InferAddressSpaces.cpp b/llvm/lib/Transforms/Scalar/InferAddressSpaces.cpp
index 830c15249582c..87b885447cc02 100644
--- a/llvm/lib/Transforms/Scalar/InferAddressSpaces.cpp
+++ b/llvm/lib/Transforms/Scalar/InferAddressSpaces.cpp
@@ -401,6 +401,13 @@ bool InferAddressSpacesImpl::rewriteIntrinsicOperands(IntrinsicInst *II,
     II->setCalledFunction(NewDecl);
     return true;
   }
+  case Intrinsic::prefetch: {
+    Function *NewDecl =
+        Intrinsic::getDeclaration(M, II->getIntrinsicID(), {NewV->getType()});
+    II->setArgOperand(0, NewV);
+    II->setCalledFunction(NewDecl);
+    return true;
+  }
   default: {
     Value *Rewrite = TTI->rewriteIntrinsicWithAddressSpace(II, OldV, NewV);
     if (!Rewrite)
@@ -423,6 +430,7 @@ void InferAddressSpacesImpl::collectRewritableIntrinsicOperands(
                                                  PostorderStack, Visited);
     break;
   case Intrinsic::masked_gather:
+  case Intrinsic::prefetch:
     appendsFlatAddressExpressionToPostorderStack(II->getArgOperand(0),
                                                  PostorderStack, Visited);
     break;
diff --git a/llvm/test/Transforms/InferAddressSpaces/AMDGPU/prefetch.ll b/llvm/test/Transforms/InferAddressSpaces/AMDGPU/prefetch.ll
new file mode 100644
index 0000000000000..e2c12c4c37141
--- /dev/null
+++ b/llvm/test/Transforms/InferAddressSpaces/AMDGPU/prefetch.ll
@@ -0,0 +1,59 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
+; RUN: opt -S -mtriple=amdgcn-amd-amdhsa -passes=infer-address-spaces %s | FileCheck %s
+
+define void @prefetch_shared_to_flat(ptr addrspace(3) %group.ptr) {
+; CHECK-LABEL: define void @prefetch_shared_to_flat(
+; CHECK-SAME: ptr addrspace(3) [[GROUP_PTR:%.*]]) {
+; CHECK-NEXT:    tail call void @llvm.prefetch.p3(ptr addrspace(3) [[GROUP_PTR]], i32 0, i32 0, i32 1)
+; CHECK-NEXT:    ret void
+;
+  %cast = addrspacecast ptr addrspace(3) %group.ptr to ptr
+  tail call void @llvm.prefetch.p0(ptr %cast, i32 0, i32 0, i32 1)
+  ret void
+}
+
+define void @prefetch_global_to_flat(ptr addrspace(1) %global.ptr) {
+; CHECK-LABEL: define void @prefetch_global_to_flat(
+; CHECK-SAME: ptr addrspace(1) [[GLOBAL_PTR:%.*]]) {
+; CHECK-NEXT:    tail call void @llvm.prefetch.p1(ptr addrspace(1) [[GLOBAL_PTR]], i32 0, i32 0, i32 1)
+; CHECK-NEXT:    ret void
+;
+  %cast = addrspacecast ptr addrspace(1) %global.ptr to ptr
+  tail call void @llvm.prefetch.p0(ptr addrspace(0) %cast, i32 0, i32 0, i32 1)
+  ret void
+}
+
+define void @prefetch_constant_to_flat(ptr addrspace(4) %const.ptr) {
+; CHECK-LABEL: define void @prefetch_constant_to_flat(
+; CHECK-SAME: ptr addrspace(4) [[CONST_PTR:%.*]]) {
+; CHECK-NEXT:    tail call void @llvm.prefetch.p4(ptr addrspace(4) [[CONST_PTR]], i32 0, i32 0, i32 1)
+; CHECK-NEXT:    ret void
+;
+  %cast = addrspacecast ptr addrspace(4) %const.ptr to ptr
+  tail call void @llvm.prefetch.p0(ptr %cast, i32 0, i32 0, i32 1)
+  ret void
+}
+
+define void @prefetch_flat_to_shared(ptr %flat.ptr) {
+; CHECK-LABEL: define void @prefetch_flat_to_shared(
+; CHECK-SAME: ptr [[FLAT_PTR:%.*]]) {
+; CHECK-NEXT:    [[CAST:%.*]] = addrspacecast ptr [[FLAT_PTR]] to ptr addrspace(3)
+; CHECK-NEXT:    tail call void @llvm.prefetch.p3(ptr addrspace(3) [[CAST]], i32 0, i32 0, i32 1)
+; CHECK-NEXT:    ret void
+;
+  %cast = addrspacecast ptr %flat.ptr to ptr addrspace(3)
+  tail call void @llvm.prefetch.p3(ptr addrspace(3) %cast, i32 0, i32 0, i32 1)
+  ret void
+}
+
+define void @prefetch_flat_to_global(ptr %flat.ptr) {
+; CHECK-LABEL: define void @prefetch_flat_to_global(
+; CHECK-SAME: ptr [[FLAT_PTR:%.*]]) {
+; CHECK-NEXT:    [[CAST:%.*]] = addrspacecast ptr [[FLAT_PTR]] to ptr addrspace(1)
+; CHECK-NEXT:    tail call void @llvm.prefetch.p1(ptr addrspace(1) [[CAST]], i32 0, i32 0, i32 1)
+; CHECK-NEXT:    ret void
+;
+  %cast = addrspacecast ptr %flat.ptr to ptr addrspace(1)
+  tail call void @llvm.prefetch.p1(ptr addrspace(1) %cast, i32 0, i32 0, i32 1)
+  ret void
+}