AMDGPU: Update live intervals in convertToThreeAddress (#104610)

Fixes #98741

2 files changed, 156 insertions, 26 deletions

diff --git a/llvm/lib/Target/AMDGPU/SIInstrInfo.cpp b/llvm/lib/Target/AMDGPU/SIInstrInfo.cpp
index 90e11df..c6f28af 100644
--- a/llvm/lib/Target/AMDGPU/SIInstrInfo.cpp
+++ b/llvm/lib/Target/AMDGPU/SIInstrInfo.cpp
@@ -4059,17 +4059,37 @@ MachineInstr *SIInstrInfo::convertToThreeAddress(MachineInstr &MI,
        !RI.isSGPRReg(MBB.getParent()->getRegInfo(), Src0->getReg()))) {
     MachineInstr *DefMI;
     const auto killDef = [&]() -> void {
-      const MachineRegisterInfo &MRI = MBB.getParent()->getRegInfo();
+      MachineRegisterInfo &MRI = MBB.getParent()->getRegInfo();
       // The only user is the instruction which will be killed.
       Register DefReg = DefMI->getOperand(0).getReg();
-      if (!MRI.hasOneNonDBGUse(DefReg))
-        return;
-      // We cannot just remove the DefMI here, calling pass will crash.
-      DefMI->setDesc(get(AMDGPU::IMPLICIT_DEF));
-      for (unsigned I = DefMI->getNumOperands() - 1; I != 0; --I)
-        DefMI->removeOperand(I);
-      if (LV)
-        LV->getVarInfo(DefReg).AliveBlocks.clear();
+
+      if (MRI.hasOneNonDBGUse(DefReg)) {
+        // We cannot just remove the DefMI here, calling pass will crash.
+        DefMI->setDesc(get(AMDGPU::IMPLICIT_DEF));
+        DefMI->getOperand(0).setIsDead(true);
+        for (unsigned I = DefMI->getNumOperands() - 1; I != 0; --I)
+          DefMI->removeOperand(I);
+        if (LV)
+          LV->getVarInfo(DefReg).AliveBlocks.clear();
+      }
+
+      if (LIS) {
+        LiveInterval &DefLI = LIS->getInterval(DefReg);
+
+        // We cannot delete the original instruction here, so hack out the use
+        // in the original instruction with a dummy register so we can use
+        // shrinkToUses to deal with any multi-use edge cases. Other targets do
+        // not have the complexity of deleting a use to consider here.
+        Register DummyReg = MRI.cloneVirtualRegister(DefReg);
+        for (MachineOperand &MIOp : MI.uses()) {
+          if (MIOp.isReg() && MIOp.getReg() == DefReg) {
+            MIOp.setIsUndef(true);
+            MIOp.setReg(DummyReg);
+          }
+        }
+
+        LIS->shrinkToUses(&DefLI);
+      }
     };
 
     int64_t Imm;
@@ -4107,6 +4127,7 @@ MachineInstr *SIInstrInfo::convertToThreeAddress(MachineInstr &MI,
                   .add(*Src2)
                   .setMIFlags(MI.getFlags());
         updateLiveVariables(LV, MI, *MIB);
+
         if (LIS)
           LIS->ReplaceMachineInstrInMaps(MI, *MIB);
         killDef();
@@ -4129,6 +4150,7 @@ MachineInstr *SIInstrInfo::convertToThreeAddress(MachineInstr &MI,
                   .add(*Src2)
                   .setMIFlags(MI.getFlags());
         updateLiveVariables(LV, MI, *MIB);
+
         if (LIS)
           LIS->ReplaceMachineInstrInMaps(MI, *MIB);
         if (DefMI)
diff --git a/llvm/test/CodeGen/AMDGPU/gfx10-twoaddr-fma.mir b/llvm/test/CodeGen/AMDGPU/gfx10-twoaddr-fma.mir
index 1768e39..f814dd3 100644
--- a/llvm/test/CodeGen/AMDGPU/gfx10-twoaddr-fma.mir
+++ b/llvm/test/CodeGen/AMDGPU/gfx10-twoaddr-fma.mir
@@ -1,33 +1,138 @@
-# RUN: llc -mtriple=amdgcn -mcpu=gfx1010 %s -run-pass twoaddressinstruction -verify-machineinstrs -o - | FileCheck --check-prefixes=GFX10 %s
-# RUN: llc -mtriple=amdgcn -mcpu=gfx1010 %s --passes=two-address-instruction -verify-each -o - | FileCheck --check-prefixes=GFX10 %s
+# RUN: llc -mtriple=amdgcn -mcpu=gfx1010 -run-pass=twoaddressinstruction -verify-machineinstrs -o - %s | FileCheck --check-prefixes=GFX10,GFX10-NOLIS %s
+# RUN: llc -mtriple=amdgcn -mcpu=gfx1010 -passes=two-address-instruction -verify-each -o - %s | FileCheck --check-prefixes=GFX10,GFX10-NOLIS %s
+# RUN: llc -mtriple=amdgcn -mcpu=gfx1010 -run-pass=liveintervals,twoaddressinstruction -verify-machineinstrs -o - %s | FileCheck --check-prefixes=GFX10,GFX10-LIS %s
+
 
 # GFX10-LABEL: name: test_fmamk_reg_imm_f16
-# GFX10: %2:vgpr_32 = IMPLICIT_DEF
+# GFX10: dead %2:vgpr_32 = IMPLICIT_DEF
 # GFX10-NOT: V_MOV_B32
-# GFX10: V_FMAMK_F16 killed %0.sub0, 1078523331, killed %1, implicit $mode, implicit $exec
+# GFX10-NOLIS: V_FMAMK_F16 killed %0.sub0, 1078523331, killed %1, implicit $mode, implicit $exec
+# GFX10-LIS: V_FMAMK_F16 %0.sub0, 1078523331, %1, implicit $mode, implicit $exec
 ---
 name:            test_fmamk_reg_imm_f16
-registers:
-  - { id: 0, class: vreg_64 }
-  - { id: 1, class: vgpr_32 }
-  - { id: 2, class: vgpr_32 }
-  - { id: 3, class: vgpr_32 }
+tracksRegLiveness: true
 body:             |
   bb.0:
 
-    %0 = IMPLICIT_DEF
-    %1 = COPY %0.sub1
-    %2 = V_MOV_B32_e32 1078523331, implicit $exec
-    %3 = V_FMAC_F16_e32 killed %0.sub0, %2, killed %1, implicit $mode, implicit $exec
+    %0:vreg_64 = IMPLICIT_DEF
+    %1:vgpr_32 = COPY %0.sub1
+    %2:vgpr_32 = V_MOV_B32_e32 1078523331, implicit $exec
+    %3:vgpr_32 = V_FMAC_F16_e32 killed %0.sub0, %2, killed %1, implicit $mode, implicit $exec
+
+...
+
+# GFX10-LABEL: name: test_fmamk_reg_imm_f16__imm_is_subreg
+# GFX10: %0:vreg_64 = IMPLICIT_DEF
+# GFX10: %1:vgpr_32 = COPY %0.sub1
+# GFX10: dead undef %2.sub0:vreg_64 = IMPLICIT_DEF
+# GFX10-NOLIS: %3:vgpr_32 = V_FMAMK_F16 killed %0.sub0, 1078523331, killed %1, implicit $mode, implicit $exec
+# GFX10-LIS: %3:vgpr_32 = V_FMAMK_F16 %0.sub0, 1078523331, %1, implicit $mode, implicit $exec
+---
+name:            test_fmamk_reg_imm_f16__imm_is_subreg
+tracksRegLiveness: true
+body:             |
+  bb.0:
+
+    %0:vreg_64 = IMPLICIT_DEF
+    %1:vgpr_32 = COPY %0.sub1
+    undef %2.sub0:vreg_64 = V_MOV_B32_e32 1078523331, implicit $exec
+    %3:vgpr_32 = V_FMAC_F16_e32 killed %0.sub0, %2.sub0, killed %1, implicit $mode, implicit $exec
+
+...
+
+# GFX10-LABEL: name: test_fmamk_reg_imm_f16__imm_is_subreg_fully_defined
+# GFX10: %0:vreg_64 = IMPLICIT_DEF
+# GFX10: %1:vgpr_32 = COPY %0.sub1
+# GFX10: undef %2.sub1:vreg_64 = V_MOV_B32_e32 9999, implicit $exec
+# GFX10: %2.sub0:vreg_64 = V_MOV_B32_e32 1078523331, implicit $exec
+# GFX10-NOLIS: %3:vgpr_32 = V_FMA_F16_gfx9_e64 0, killed %0.sub0, 0, %2.sub0, 0, killed %1, 0, 0, 0, implicit $mode, implicit $e
+# GFX10-LIS: %3:vgpr_32 = V_FMA_F16_gfx9_e64 0, %0.sub0, 0, %2.sub0, 0, %1, 0, 0, 0, implicit $mode, implicit $e
+---
+name:            test_fmamk_reg_imm_f16__imm_is_subreg_fully_defined
+tracksRegLiveness: true
+body:             |
+  bb.0:
+    %0:vreg_64 = IMPLICIT_DEF
+    %1:vgpr_32 = COPY %0.sub1
+    undef %2.sub1 = V_MOV_B32_e32 9999, implicit $exec
+    %2.sub0:vreg_64 = V_MOV_B32_e32 1078523331, implicit $exec
+    %3:vgpr_32 = V_FMAC_F16_e32 killed %0.sub0, %2.sub0, killed %1, implicit $mode, implicit $exec
+
+...
+
+# GFX10-LABEL: name: test_fmamk_reg_imm_f16__use_imm_before_mac
+# GFX10: %0:vreg_64 = IMPLICIT_DEF
+# GFX10: %1:vgpr_32 = COPY %0.sub1
+# GFX10: %2:vgpr_32 = V_MOV_B32_e32 1078523331, implicit $exec
+# GFX10: S_NOP 0, implicit %2
+# GFX10-NOLIS: %3:vgpr_32 = V_FMAMK_F16 killed %0.sub0, 1078523331, killed %1, implicit $mode, implicit $exec
+# GFX10-LIS: %3:vgpr_32 = V_FMAMK_F16 %0.sub0, 1078523331, %1, implicit $mode, implicit $exec
+---
+name:            test_fmamk_reg_imm_f16__use_imm_before_mac
+tracksRegLiveness: true
+body:             |
+  bb.0:
+
+    %0:vreg_64 = IMPLICIT_DEF
+    %1:vgpr_32 = COPY %0.sub1
+    %2:vgpr_32 = V_MOV_B32_e32 1078523331, implicit $exec
+    S_NOP 0, implicit %2
+    %3:vgpr_32 = V_FMAC_F16_e32 killed %0.sub0, %2, killed %1, implicit $mode, implicit $exec
+
+...
+
+# GFX10-LABEL: name: test_fmamk_reg_imm_f16__use_imm_after_mac
+# GFX10: %0:vreg_64 = IMPLICIT_DEF
+# GFX10: %1:vgpr_32 = COPY %0.sub1
+# GFX10: %2:vgpr_32 = V_MOV_B32_e32 1078523331, implicit $exec
+# GFX10-NOLIS: %3:vgpr_32 = V_FMAMK_F16 killed %0.sub0, 1078523331, killed %1, implicit $mode, implicit $exec
+# GFX10-LIS: %3:vgpr_32 = V_FMAMK_F16 %0.sub0, 1078523331, %1, implicit $mode, implicit $exec
+---
+name:            test_fmamk_reg_imm_f16__use_imm_after_mac
+tracksRegLiveness: true
+body:             |
+  bb.0:
+
+    %0:vreg_64 = IMPLICIT_DEF
+    %1:vgpr_32 = COPY %0.sub1
+    %2:vgpr_32 = V_MOV_B32_e32 1078523331, implicit $exec
+    %3:vgpr_32 = V_FMAC_F16_e32 killed %0.sub0, %2, killed %1, implicit $mode, implicit $exec
+    S_NOP 0, implicit %2
+
+...
+
+# GFX10-LABEL: name: test_fmamk_reg_imm_f16__use_imm_before_after_mac
+# GFX10: %0:vreg_64 = IMPLICIT_DEF
+# GFX10: %1:vgpr_32 = COPY %0.sub1
+# GFX10: %2:vgpr_32 = V_MOV_B32_e32 1078523331, implicit $exec
+# GFX10: S_NOP 0, implicit %2
+# GFX10-NOLIS: %3:vgpr_32 = V_FMAMK_F16 killed %0.sub0, 1078523331, killed %1, implicit $mode, implicit $exec
+# GFX10-LIS: %3:vgpr_32 = V_FMAMK_F16 %0.sub0, 1078523331, %1, implicit $mode, implicit $exec
+# GFX10: S_NOP 0, implicit %2
+
+---
+name:            test_fmamk_reg_imm_f16__use_imm_before_after_mac
+tracksRegLiveness: true
+body:             |
+  bb.0:
+
+    %0:vreg_64 = IMPLICIT_DEF
+    %1:vgpr_32 = COPY %0.sub1
+    %2:vgpr_32 = V_MOV_B32_e32 1078523331, implicit $exec
+    S_NOP 0, implicit %2
+    %3:vgpr_32 = V_FMAC_F16_e32 killed %0.sub0, %2, killed %1, implicit $mode, implicit $exec
+    S_NOP 0, implicit %2
 
 ...
 
 # GFX10-LABEL: name: test_fmamk_imm_reg_f16
-# GFX10: %2:vgpr_32 = IMPLICIT_DEF
+# GFX10: dead %2:vgpr_32 = IMPLICIT_DEF
 # GFX10-NOT: V_MOV_B32
-# GFX10: V_FMAMK_F16 killed %0.sub0, 1078523331, killed %1, implicit $mode, implicit $exec
+# GFX10-NOLIS: V_FMAMK_F16 killed %0.sub0, 1078523331, killed %1, implicit $mode, implicit $exec
+# GFX10-LIS: V_FMAMK_F16 %0.sub0, 1078523331, %1, implicit $mode, implicit $exec
 ---
 name:            test_fmamk_imm_reg_f16
+tracksRegLiveness: true
 registers:
   - { id: 0, class: vreg_64 }
   - { id: 1, class: vgpr_32 }
@@ -46,9 +151,11 @@ body:             |
 # GFX10-LABEL: name: test_fmaak_f16
 # GFX10: %1:vgpr_32 = V_MOV_B32_e32 1078523331, implicit $exec
 # GFX10-NOT: V_MOV_B32
-# GFX10: V_FMAAK_F16 killed %0.sub0, %0.sub1, 1078523331, implicit $mode, implicit $exec
+# GFX10-NOLIS: V_FMAAK_F16 killed %0.sub0, %0.sub1, 1078523331, implicit $mode, implicit $exec
+# GFX10-LIS: V_FMAAK_F16 %0.sub0, %0.sub1, 1078523331, implicit $mode, implicit $exec
 ---
 name:            test_fmaak_f16
+tracksRegLiveness: true
 registers:
   - { id: 0, class: vreg_64 }
   - { id: 1, class: vgpr_32 }
@@ -65,7 +172,8 @@ body:             |
 # GFX10-LABEL: name: test_fmaak_inline_literal_f16
 # GFX10: %1:vgpr_32 = V_MOV_B32_e32 49664, implicit $exec
 # GFX10-NOT: V_MOV_B32
-# GFX10: %2:vgpr_32 = V_FMAAK_F16 16384, killed %0, 49664, implicit $mode, implicit $exec
+# GFX10-NOLIS: %2:vgpr_32 = V_FMAAK_F16 16384, killed %0, 49664, implicit $mode, implicit $exec
+# GFX10-LIS: %2:vgpr_32 = V_FMAAK_F16 16384, %0, 49664, implicit $mode, implicit $exec
 
 ---
 name:            test_fmaak_inline_literal_f16