[llvm] AMDGPU: Implement getRoundingControlRegisters (PR #92884)

[Matt Arsenault via llvm-commits]

https://github.com/arsenm created https://github.com/llvm/llvm-project/pull/92884

None

>From 6ece9b36a057f0abf0a38551a935c49aefcb115c Mon Sep 17 00:00:00 2001
From: Matt Arsenault <Matthew.Arsenault at amd.com>
Date: Tue, 21 May 2024 10:33:03 +0200
Subject: [PATCH] AMDGPU: Implement getRoundingControlRegisters

---
 llvm/lib/Target/AMDGPU/SIISelLowering.cpp     |  5 ++
 llvm/lib/Target/AMDGPU/SIISelLowering.h       |  2 +
 .../CodeGen/AMDGPU/call-defs-mode-register.ll | 57 +++++++++++++++++++
 3 files changed, 64 insertions(+)
 create mode 100644 llvm/test/CodeGen/AMDGPU/call-defs-mode-register.ll

diff --git a/llvm/lib/Target/AMDGPU/SIISelLowering.cpp b/llvm/lib/Target/AMDGPU/SIISelLowering.cpp
index 42e1c1ce764c4..45a16a14996ee 100644
--- a/llvm/lib/Target/AMDGPU/SIISelLowering.cpp
+++ b/llvm/lib/Target/AMDGPU/SIISelLowering.cpp
@@ -957,6 +957,11 @@ const GCNSubtarget *SITargetLowering::getSubtarget() const {
   return Subtarget;
 }
 
+ArrayRef<MCPhysReg> SITargetLowering::getRoundingControlRegisters() const {
+  static const MCPhysReg RCRegs[] = {AMDGPU::MODE};
+  return RCRegs;
+}
+
 //===----------------------------------------------------------------------===//
 // TargetLowering queries
 //===----------------------------------------------------------------------===//
diff --git a/llvm/lib/Target/AMDGPU/SIISelLowering.h b/llvm/lib/Target/AMDGPU/SIISelLowering.h
index 08aa2a5991631..fed73f48840fd 100644
--- a/llvm/lib/Target/AMDGPU/SIISelLowering.h
+++ b/llvm/lib/Target/AMDGPU/SIISelLowering.h
@@ -287,6 +287,8 @@ class SITargetLowering final : public AMDGPUTargetLowering {
 
   const GCNSubtarget *getSubtarget() const;
 
+  ArrayRef<MCPhysReg> getRoundingControlRegisters() const override;
+
   bool isFPExtFoldable(const SelectionDAG &DAG, unsigned Opcode, EVT DestVT,
                        EVT SrcVT) const override;
 
diff --git a/llvm/test/CodeGen/AMDGPU/call-defs-mode-register.ll b/llvm/test/CodeGen/AMDGPU/call-defs-mode-register.ll
new file mode 100644
index 0000000000000..7ad24302d7834
--- /dev/null
+++ b/llvm/test/CodeGen/AMDGPU/call-defs-mode-register.ll
@@ -0,0 +1,57 @@
+; NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py UTC_ARGS: --version 5
+; RUN: llc -mtriple=amdgcn-amd-amdhsa -mcpu=gfx900 -simplify-mir -stop-after=finalize-isel < %s | FileCheck %s
+
+; Check that call / asm get an implicit-def $mode added to them in
+; strictfp functions.
+
+declare protected void @maybe_defs_mode() #0
+
+define float @call_changes_mode(float %x, float %y) #0 {
+  ; CHECK-LABEL: name: call_changes_mode
+  ; CHECK: bb.0 (%ir-block.0):
+  ; CHECK-NEXT:   liveins: $vgpr0, $vgpr1
+  ; CHECK-NEXT: {{  $}}
+  ; CHECK-NEXT:   [[COPY:%[0-9]+]]:vgpr_32 = COPY $vgpr1
+  ; CHECK-NEXT:   [[COPY1:%[0-9]+]]:vgpr_32 = COPY $vgpr0
+  ; CHECK-NEXT:   ADJCALLSTACKUP 0, 0, implicit-def dead $scc, implicit-def $sgpr32, implicit $sgpr32
+  ; CHECK-NEXT:   [[SI_PC_ADD_REL_OFFSET:%[0-9]+]]:sreg_64 = SI_PC_ADD_REL_OFFSET target-flags(amdgpu-rel32-lo) @maybe_defs_mode, target-flags(amdgpu-rel32-hi) @maybe_defs_mode, implicit-def dead $scc
+  ; CHECK-NEXT:   [[COPY2:%[0-9]+]]:sgpr_128 = COPY $sgpr0_sgpr1_sgpr2_sgpr3
+  ; CHECK-NEXT:   $sgpr0_sgpr1_sgpr2_sgpr3 = COPY [[COPY2]]
+  ; CHECK-NEXT:   $sgpr30_sgpr31 = SI_CALL killed [[SI_PC_ADD_REL_OFFSET]], @maybe_defs_mode, csr_amdgpu, implicit $sgpr0_sgpr1_sgpr2_sgpr3, implicit-def $mode
+  ; CHECK-NEXT:   ADJCALLSTACKDOWN 0, 0, implicit-def dead $scc, implicit-def $sgpr32, implicit $sgpr32
+  ; CHECK-NEXT:   [[V_ADD_F32_e64_:%[0-9]+]]:vgpr_32 = nofpexcept V_ADD_F32_e64 0, [[COPY1]], 0, [[COPY]], 0, 0, implicit $mode, implicit $exec
+  ; CHECK-NEXT:   $vgpr0 = COPY [[V_ADD_F32_e64_]]
+  ; CHECK-NEXT:   SI_RETURN implicit $vgpr0
+  call void @maybe_defs_mode()
+  %val = call float @llvm.experimental.constrained.fadd.f32(float %x, float %y, metadata !"round.dynamic", metadata !"fpexcept.ignore")
+  ret float %val
+}
+
+define void @tail_call_changes_mode() #0 {
+  ; CHECK-LABEL: name: tail_call_changes_mode
+  ; CHECK: bb.0 (%ir-block.0):
+  ; CHECK-NEXT:   [[SI_PC_ADD_REL_OFFSET:%[0-9]+]]:ccr_sgpr_64 = SI_PC_ADD_REL_OFFSET target-flags(amdgpu-rel32-lo) @maybe_defs_mode, target-flags(amdgpu-rel32-hi) @maybe_defs_mode, implicit-def dead $scc
+  ; CHECK-NEXT:   SI_TCRETURN killed [[SI_PC_ADD_REL_OFFSET]], @maybe_defs_mode, 0, csr_amdgpu, implicit-def $mode
+  tail call void @maybe_defs_mode()
+  ret void
+}
+
+define float @asm_changes_mode(float %x, float %y) #0 {
+  ; CHECK-LABEL: name: asm_changes_mode
+  ; CHECK: bb.0 (%ir-block.0):
+  ; CHECK-NEXT:   liveins: $vgpr0, $vgpr1
+  ; CHECK-NEXT: {{  $}}
+  ; CHECK-NEXT:   [[COPY:%[0-9]+]]:vgpr_32 = COPY $vgpr1
+  ; CHECK-NEXT:   [[COPY1:%[0-9]+]]:vgpr_32 = COPY $vgpr0
+  ; CHECK-NEXT:   INLINEASM &"; maybe defs mode", 1 /* sideeffect attdialect */
+  ; CHECK-NEXT:   [[V_ADD_F32_e64_:%[0-9]+]]:vgpr_32 = nofpexcept V_ADD_F32_e64 0, [[COPY1]], 0, [[COPY]], 0, 0, implicit $mode, implicit $exec
+  ; CHECK-NEXT:   $vgpr0 = COPY [[V_ADD_F32_e64_]]
+  ; CHECK-NEXT:   SI_RETURN implicit $vgpr0
+  call void asm sideeffect "; maybe defs mode", ""()
+  %val = call float @llvm.experimental.constrained.fadd.f32(float %x, float %y, metadata !"round.dynamic", metadata !"fpexcept.ignore")
+  ret float %val
+}
+
+declare float @llvm.experimental.constrained.fadd.f32(float, float, metadata, metadata)
+
+attributes #0 = { strictfp "amdgpu-no-completion-action" "amdgpu-no-default-queue" "amdgpu-no-dispatch-id" "amdgpu-no-dispatch-ptr" "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"  }