[AMDGPU] Allow forming overflow op and folding abd to usubo if it is legal.

Because usubo and uaddo are legal in AMDGPU in 32 bits, we want to use it whenever possible.

Author: AZero13

llvm/include/llvm/CodeGen/TargetLowering.h

@@ -3455,6 +3455,10 @@ class LLVM_ABI TargetLoweringBase {
   /// matching of other patterns.
   virtual bool shouldFormOverflowOp(unsigned Opcode, EVT VT,
                                     bool MathUsed) const {
+    // Form it if it is legal.
+    if (isOperationLegal(Opcode, VT))
+      return true;
+
     // TODO: The default logic is inherited from code in CodeGenPrepare.
     // The opcode should not make a difference by default?
     if (Opcode != ISD::UADDO)

llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp

@@ -9788,7 +9788,8 @@ SDValue TargetLowering::expandABD(SDNode *N, SelectionDAG &DAG) const {
   // flag if the (scalar) type is illegal as this is more likely to legalize
   // cleanly:
   // abdu(lhs, rhs) -> sub(xor(sub(lhs, rhs), uof(lhs, rhs)), uof(lhs, rhs))
-  if (!IsSigned && VT.isScalarInteger() && !isTypeLegal(VT)) {
+  if (!IsSigned && (isOperationLegal(ISD::USUBO, VT) ||
+                    (VT.isScalarInteger() && !isTypeLegal(VT)))) {
     SDValue USubO =
         DAG.getNode(ISD::USUBO, dl, DAG.getVTList(VT, MVT::i1), {LHS, RHS});
     SDValue Cmp = DAG.getNode(ISD::SIGN_EXTEND, dl, VT, USubO.getValue(1));

llvm/test/CodeGen/AMDGPU/addrspacecast-constantexpr.ll

@@ -169,6 +169,6 @@ attributes #1 = { nounwind }
 
 ;.
 ; HSA: attributes #[[ATTR0:[0-9]+]] = { nocallback nofree nounwind willreturn memory(argmem: readwrite) }
-; HSA: attributes #[[ATTR1]] = { nounwind "amdgpu-agpr-alloc"="0" "amdgpu-no-completion-action" "amdgpu-no-default-queue" "amdgpu-no-dispatch-id" "amdgpu-no-dispatch-ptr" "amdgpu-no-flat-scratch-init" "amdgpu-no-heap-ptr" "amdgpu-no-hostcall-ptr" "amdgpu-no-implicitarg-ptr" "amdgpu-no-lds-kernel-id" "amdgpu-no-multigrid-sync-arg" "amdgpu-no-queue-ptr" "amdgpu-no-workgroup-id-x" "amdgpu-no-workgroup-id-y" "amdgpu-no-workgroup-id-z" "amdgpu-no-workitem-id-x" "amdgpu-no-workitem-id-y" "amdgpu-no-workitem-id-z" "uniform-work-group-size"="false" }
-; HSA: attributes #[[ATTR2]] = { nounwind "amdgpu-agpr-alloc"="0" "amdgpu-no-completion-action" "amdgpu-no-default-queue" "amdgpu-no-dispatch-id" "amdgpu-no-dispatch-ptr" "amdgpu-no-flat-scratch-init" "amdgpu-no-heap-ptr" "amdgpu-no-hostcall-ptr" "amdgpu-no-lds-kernel-id" "amdgpu-no-multigrid-sync-arg" "amdgpu-no-queue-ptr" "amdgpu-no-workgroup-id-x" "amdgpu-no-workgroup-id-y" "amdgpu-no-workgroup-id-z" "amdgpu-no-workitem-id-x" "amdgpu-no-workitem-id-y" "amdgpu-no-workitem-id-z" "uniform-work-group-size"="false" }
+; HSA: attributes #[[ATTR1]] = { nounwind "amdgpu-agpr-alloc"="0" "amdgpu-no-completion-action" "amdgpu-no-default-queue" "amdgpu-no-dispatch-id" "amdgpu-no-dispatch-ptr" "amdgpu-no-flat-scratch-init" "amdgpu-no-heap-ptr" "amdgpu-no-hostcall-ptr" "amdgpu-no-implicitarg-ptr" "amdgpu-no-lds-kernel-id" "amdgpu-no-multigrid-sync-arg" "amdgpu-no-queue-ptr" "amdgpu-no-workgroup-id-x" "amdgpu-no-workgroup-id-y" "amdgpu-no-workgroup-id-z" "amdgpu-no-workitem-id-x" "amdgpu-no-workitem-id-y" "amdgpu-no-workitem-id-z" "amdgpu-waves-per-eu"="4,10" "uniform-work-group-size"="false" }
+; HSA: attributes #[[ATTR2]] = { nounwind "amdgpu-agpr-alloc"="0" "amdgpu-no-completion-action" "amdgpu-no-default-queue" "amdgpu-no-dispatch-id" "amdgpu-no-dispatch-ptr" "amdgpu-no-flat-scratch-init" "amdgpu-no-heap-ptr" "amdgpu-no-hostcall-ptr" "amdgpu-no-lds-kernel-id" "amdgpu-no-multigrid-sync-arg" "amdgpu-no-queue-ptr" "amdgpu-no-workgroup-id-x" "amdgpu-no-workgroup-id-y" "amdgpu-no-workgroup-id-z" "amdgpu-no-workitem-id-x" "amdgpu-no-workitem-id-y" "amdgpu-no-workitem-id-z" "amdgpu-waves-per-eu"="4,10" "uniform-work-group-size"="false" }
 ;.

llvm/test/CodeGen/AMDGPU/amdgpu-attributor-no-agpr.ll

@@ -105,7 +105,7 @@ declare void @unknown()
 
 define amdgpu_kernel void @kernel_calls_extern() {
 ; CHECK-LABEL: define amdgpu_kernel void @kernel_calls_extern(
-; CHECK-SAME: ) #[[ATTR2:[0-9]+]] {
+; CHECK-SAME: ) #[[ATTR3:[0-9]+]] {
 ; CHECK-NEXT:    call void @unknown()
 ; CHECK-NEXT:    ret void
 ;
@@ -115,8 +115,8 @@ define amdgpu_kernel void @kernel_calls_extern() {
 
 define amdgpu_kernel void @kernel_calls_extern_marked_callsite() {
 ; CHECK-LABEL: define amdgpu_kernel void @kernel_calls_extern_marked_callsite(
-; CHECK-SAME: ) #[[ATTR2]] {
-; CHECK-NEXT:    call void @unknown() #[[ATTR6:[0-9]+]]
+; CHECK-SAME: ) #[[ATTR3]] {
+; CHECK-NEXT:    call void @unknown() #[[ATTR7:[0-9]+]]
 ; CHECK-NEXT:    ret void
 ;
   call void @unknown() #0
@@ -125,7 +125,7 @@ define amdgpu_kernel void @kernel_calls_extern_marked_callsite() {
 
 define amdgpu_kernel void @kernel_calls_indirect(ptr %indirect) {
 ; CHECK-LABEL: define amdgpu_kernel void @kernel_calls_indirect(
-; CHECK-SAME: ptr [[INDIRECT:%.*]]) #[[ATTR2]] {
+; CHECK-SAME: ptr [[INDIRECT:%.*]]) #[[ATTR3]] {
 ; CHECK-NEXT:    call void [[INDIRECT]]()
 ; CHECK-NEXT:    ret void
 ;
@@ -135,8 +135,8 @@ define amdgpu_kernel void @kernel_calls_indirect(ptr %indirect) {
 
 define amdgpu_kernel void @kernel_calls_indirect_marked_callsite(ptr %indirect) {
 ; CHECK-LABEL: define amdgpu_kernel void @kernel_calls_indirect_marked_callsite(
-; CHECK-SAME: ptr [[INDIRECT:%.*]]) #[[ATTR2]] {
-; CHECK-NEXT:    call void [[INDIRECT]]() #[[ATTR6]]
+; CHECK-SAME: ptr [[INDIRECT:%.*]]) #[[ATTR3]] {
+; CHECK-NEXT:    call void [[INDIRECT]]() #[[ATTR7]]
 ; CHECK-NEXT:    ret void
 ;
   call void %indirect() #0
@@ -254,11 +254,12 @@ define amdgpu_kernel void @indirect_calls_none_agpr(i1 %cond) {
 
 attributes #0 = { "amdgpu-agpr-alloc"="0" }
 ;.
-; CHECK: attributes #[[ATTR0]] = { "amdgpu-no-completion-action" "amdgpu-no-default-queue" "amdgpu-no-dispatch-id" "amdgpu-no-dispatch-ptr" "amdgpu-no-flat-scratch-init" "amdgpu-no-heap-ptr" "amdgpu-no-hostcall-ptr" "amdgpu-no-implicitarg-ptr" "amdgpu-no-lds-kernel-id" "amdgpu-no-multigrid-sync-arg" "amdgpu-no-queue-ptr" "amdgpu-no-workgroup-id-x" "amdgpu-no-workgroup-id-y" "amdgpu-no-workgroup-id-z" "amdgpu-no-workitem-id-x" "amdgpu-no-workitem-id-y" "amdgpu-no-workitem-id-z" "target-cpu"="gfx90a" "uniform-work-group-size"="false" }
-; CHECK: attributes #[[ATTR1]] = { "amdgpu-agpr-alloc"="0" "amdgpu-no-completion-action" "amdgpu-no-default-queue" "amdgpu-no-dispatch-id" "amdgpu-no-dispatch-ptr" "amdgpu-no-flat-scratch-init" "amdgpu-no-heap-ptr" "amdgpu-no-hostcall-ptr" "amdgpu-no-implicitarg-ptr" "amdgpu-no-lds-kernel-id" "amdgpu-no-multigrid-sync-arg" "amdgpu-no-queue-ptr" "amdgpu-no-workgroup-id-x" "amdgpu-no-workgroup-id-y" "amdgpu-no-workgroup-id-z" "amdgpu-no-workitem-id-x" "amdgpu-no-workitem-id-y" "amdgpu-no-workitem-id-z" "target-cpu"="gfx90a" "uniform-work-group-size"="false" }
-; CHECK: attributes #[[ATTR2]] = { "target-cpu"="gfx90a" "uniform-work-group-size"="false" }
-; CHECK: attributes #[[ATTR3:[0-9]+]] = { convergent nocallback nofree nosync nounwind willreturn memory(none) "target-cpu"="gfx90a" }
-; CHECK: attributes #[[ATTR4:[0-9]+]] = { nocallback nofree nosync nounwind speculatable willreturn memory(none) "target-cpu"="gfx90a" }
-; CHECK: attributes #[[ATTR5:[0-9]+]] = { nocallback nofree nounwind willreturn memory(argmem: readwrite) "target-cpu"="gfx90a" }
-; CHECK: attributes #[[ATTR6]] = { "amdgpu-agpr-alloc"="0" }
+; CHECK: attributes #[[ATTR0]] = { "amdgpu-no-completion-action" "amdgpu-no-default-queue" "amdgpu-no-dispatch-id" "amdgpu-no-dispatch-ptr" "amdgpu-no-flat-scratch-init" "amdgpu-no-heap-ptr" "amdgpu-no-hostcall-ptr" "amdgpu-no-implicitarg-ptr" "amdgpu-no-lds-kernel-id" "amdgpu-no-multigrid-sync-arg" "amdgpu-no-queue-ptr" "amdgpu-no-workgroup-id-x" "amdgpu-no-workgroup-id-y" "amdgpu-no-workgroup-id-z" "amdgpu-no-workitem-id-x" "amdgpu-no-workitem-id-y" "amdgpu-no-workitem-id-z" "amdgpu-waves-per-eu"="4,8" "target-cpu"="gfx90a" "uniform-work-group-size"="false" }
+; CHECK: attributes #[[ATTR1]] = { "amdgpu-agpr-alloc"="0" "amdgpu-no-completion-action" "amdgpu-no-default-queue" "amdgpu-no-dispatch-id" "amdgpu-no-dispatch-ptr" "amdgpu-no-flat-scratch-init" "amdgpu-no-heap-ptr" "amdgpu-no-hostcall-ptr" "amdgpu-no-implicitarg-ptr" "amdgpu-no-lds-kernel-id" "amdgpu-no-multigrid-sync-arg" "amdgpu-no-queue-ptr" "amdgpu-no-workgroup-id-x" "amdgpu-no-workgroup-id-y" "amdgpu-no-workgroup-id-z" "amdgpu-no-workitem-id-x" "amdgpu-no-workitem-id-y" "amdgpu-no-workitem-id-z" "amdgpu-waves-per-eu"="4,8" "target-cpu"="gfx90a" "uniform-work-group-size"="false" }
+; CHECK: attributes #[[ATTR2:[0-9]+]] = { "target-cpu"="gfx90a" "uniform-work-group-size"="false" }
+; CHECK: attributes #[[ATTR3]] = { "amdgpu-waves-per-eu"="4,8" "target-cpu"="gfx90a" "uniform-work-group-size"="false" }
+; CHECK: attributes #[[ATTR4:[0-9]+]] = { convergent nocallback nofree nosync nounwind willreturn memory(none) "target-cpu"="gfx90a" }
+; CHECK: attributes #[[ATTR5:[0-9]+]] = { nocallback nofree nosync nounwind speculatable willreturn memory(none) "target-cpu"="gfx90a" }
+; CHECK: attributes #[[ATTR6:[0-9]+]] = { nocallback nofree nounwind willreturn memory(argmem: readwrite) "target-cpu"="gfx90a" }
+; CHECK: attributes #[[ATTR7]] = { "amdgpu-agpr-alloc"="0" }
 ;.