From: Matt Arsenault <Matthew.Arsenault@amd.com>
Date: Fri, 2 Dec 2016 18:12:53 +0000 (+0000)
Subject: AMDGPU: Implement isCheapAddrSpaceCast
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=76a17e03e013ee9f89893eeaad7962cf07aef117;p=llvm

AMDGPU: Implement isCheapAddrSpaceCast

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@288523 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Target/AMDGPU/SIISelLowering.cpp b/lib/Target/AMDGPU/SIISelLowering.cpp
index ac5fddfd42d..ef61fc409f8 100644
--- a/lib/Target/AMDGPU/SIISelLowering.cpp
+++ b/lib/Target/AMDGPU/SIISelLowering.cpp
@@ -600,8 +600,8 @@ EVT SITargetLowering::getOptimalMemOpType(uint64_t Size, unsigned DstAlign,
 
 static bool isFlatGlobalAddrSpace(unsigned AS) {
   return AS == AMDGPUAS::GLOBAL_ADDRESS ||
-    AS == AMDGPUAS::FLAT_ADDRESS ||
-    AS == AMDGPUAS::CONSTANT_ADDRESS;
+         AS == AMDGPUAS::FLAT_ADDRESS ||
+         AS == AMDGPUAS::CONSTANT_ADDRESS;
 }
 
 bool SITargetLowering::isNoopAddrSpaceCast(unsigned SrcAS,
@@ -609,6 +609,16 @@ bool SITargetLowering::isNoopAddrSpaceCast(unsigned SrcAS,
   return isFlatGlobalAddrSpace(SrcAS) && isFlatGlobalAddrSpace(DestAS);
 }
 
+bool SITargetLowering::isCheapAddrSpaceCast(unsigned SrcAS,
+                                            unsigned DestAS) const {
+  // Flat -> private/local is a simple truncate.
+  // Flat -> global is no-op
+  if (SrcAS == AMDGPUAS::FLAT_ADDRESS)
+    return true;
+
+  return isNoopAddrSpaceCast(SrcAS, DestAS);
+}
+
 bool SITargetLowering::isMemOpUniform(const SDNode *N) const {
   const MemSDNode *MemNode = cast<MemSDNode>(N);
   const Value *Ptr = MemNode->getMemOperand()->getValue();
diff --git a/lib/Target/AMDGPU/SIISelLowering.h b/lib/Target/AMDGPU/SIISelLowering.h
index 2e14f499a85..03846fd5473 100644
--- a/lib/Target/AMDGPU/SIISelLowering.h
+++ b/lib/Target/AMDGPU/SIISelLowering.h
@@ -130,6 +130,7 @@ public:
 
   bool isMemOpUniform(const SDNode *N) const;
   bool isNoopAddrSpaceCast(unsigned SrcAS, unsigned DestAS) const override;
+  bool isCheapAddrSpaceCast(unsigned SrcAS, unsigned DestAS) const override;
 
   TargetLoweringBase::LegalizeTypeAction
   getPreferredVectorAction(EVT VT) const override;
diff --git a/test/Transforms/CodeGenPrepare/AMDGPU/sink-addrspacecast.ll b/test/Transforms/CodeGenPrepare/AMDGPU/sink-addrspacecast.ll
new file mode 100644
index 00000000000..adeba26a6d4
--- /dev/null
+++ b/test/Transforms/CodeGenPrepare/AMDGPU/sink-addrspacecast.ll
@@ -0,0 +1,121 @@
+; RUN: opt -S -codegenprepare -mtriple=amdgcn--amdhsa < %s | FileCheck %s
+
+; CHECK-LABEL: @no_sink_local_to_flat(
+; CHECK: addrspacecast
+; CHECK: br
+; CHECK-NOT: addrspacecast
+define i64 @no_sink_local_to_flat(i1 %pred, i64 addrspace(3)* %ptr) {
+  %ptr_cast = addrspacecast i64 addrspace(3)* %ptr to i64 addrspace(4)*
+  br i1 %pred, label %l1, label %l2
+
+l1:
+  %v1 = load i64, i64 addrspace(3)* %ptr
+  ret i64 %v1
+
+l2:
+  %v2 = load i64, i64 addrspace(4)* %ptr_cast
+  ret i64 %v2
+}
+
+; CHECK-LABEL: @no_sink_private_to_flat(
+; CHECK: addrspacecast
+; CHECK: br
+; CHECK-NOT: addrspacecast
+define i64 @no_sink_private_to_flat(i1 %pred, i64* %ptr) {
+  %ptr_cast = addrspacecast i64* %ptr to i64 addrspace(4)*
+  br i1 %pred, label %l1, label %l2
+
+l1:
+  %v1 = load i64, i64* %ptr
+  ret i64 %v1
+
+l2:
+  %v2 = load i64, i64 addrspace(4)* %ptr_cast
+  ret i64 %v2
+}
+
+
+; CHECK-LABEL: @sink_global_to_flat(
+; CHECK-NOT: addrspacecast
+; CHECK: br
+; CHECK: addrspacecast
+define i64 @sink_global_to_flat(i1 %pred, i64 addrspace(1)* %ptr) {
+  %ptr_cast = addrspacecast i64 addrspace(1)* %ptr to i64 addrspace(4)*
+  br i1 %pred, label %l1, label %l2
+
+l1:
+  %v1 = load i64, i64 addrspace(1)* %ptr
+  ret i64 %v1
+
+l2:
+  %v2 = load i64, i64 addrspace(4)* %ptr_cast
+  ret i64 %v2
+}
+
+; CHECK-LABEL: @sink_flat_to_global(
+; CHECK-NOT: addrspacecast
+; CHECK: br
+; CHECK: addrspacecast
+define i64 @sink_flat_to_global(i1 %pred, i64 addrspace(4)* %ptr) {
+  %ptr_cast = addrspacecast i64 addrspace(4)* %ptr to i64 addrspace(1)*
+  br i1 %pred, label %l1, label %l2
+
+l1:
+  %v1 = load i64, i64 addrspace(4)* %ptr
+  ret i64 %v1
+
+l2:
+  %v2 = load i64, i64 addrspace(1)* %ptr_cast
+  ret i64 %v2
+}
+
+; CHECK-LABEL: @sink_flat_to_constant(
+; CHECK-NOT: addrspacecast
+; CHECK: br
+; CHECK: addrspacecast
+define i64 @sink_flat_to_constant(i1 %pred, i64 addrspace(4)* %ptr) {
+  %ptr_cast = addrspacecast i64 addrspace(4)* %ptr to i64 addrspace(2)*
+  br i1 %pred, label %l1, label %l2
+
+l1:
+  %v1 = load i64, i64 addrspace(4)* %ptr
+  ret i64 %v1
+
+l2:
+  %v2 = load i64, i64 addrspace(2)* %ptr_cast
+  ret i64 %v2
+}
+
+; CHECK-LABEL: @sink_flat_to_local(
+; CHECK-NOT: addrspacecast
+; CHECK: br
+; CHECK: addrspacecast
+define i64 @sink_flat_to_local(i1 %pred, i64 addrspace(4)* %ptr) {
+  %ptr_cast = addrspacecast i64 addrspace(4)* %ptr to i64 addrspace(3)*
+  br i1 %pred, label %l1, label %l2
+
+l1:
+  %v1 = load i64, i64 addrspace(4)* %ptr
+  ret i64 %v1
+
+l2:
+  %v2 = load i64, i64 addrspace(3)* %ptr_cast
+  ret i64 %v2
+}
+
+; CHECK-LABEL: @sink_flat_to_private(
+; CHECK-NOT: addrspacecast
+; CHECK: br
+; CHECK: addrspacecast
+define i64 @sink_flat_to_private(i1 %pred, i64 addrspace(4)* %ptr) {
+  %ptr_cast = addrspacecast i64 addrspace(4)* %ptr to i64*
+  br i1 %pred, label %l1, label %l2
+
+l1:
+  %v1 = load i64, i64 addrspace(4)* %ptr
+  ret i64 %v1
+
+l2:
+  %v2 = load i64, i64* %ptr_cast
+  ret i64 %v2
+}