Revert "[RISCV] Separate doLocalPostpass into new pass and move to post vector regalloc (#88295)"

Seems to cause an address sanitizer failure on one of the buildbots related
to live intervals.

Author: lukel97

llvm/lib/Target/RISCV/RISCV.h

@@ -61,9 +61,6 @@ void initializeRISCVExpandAtomicPseudoPass(PassRegistry &);
 FunctionPass *createRISCVInsertVSETVLIPass();
 void initializeRISCVInsertVSETVLIPass(PassRegistry &);
 
-FunctionPass *createRISCVCoalesceVSETVLIPass();
-void initializeRISCVCoalesceVSETVLIPass(PassRegistry &);
-
 FunctionPass *createRISCVPostRAExpandPseudoPass();
 void initializeRISCVPostRAExpandPseudoPass(PassRegistry &);
 FunctionPass *createRISCVInsertReadWriteCSRPass();

llvm/lib/Target/RISCV/RISCVInsertVSETVLI.cpp

@@ -27,19 +27,16 @@
 #include "RISCV.h"
 #include "RISCVSubtarget.h"
 #include "llvm/ADT/Statistic.h"
-#include "llvm/CodeGen/LiveDebugVariables.h"
 #include "llvm/CodeGen/LiveIntervals.h"
-#include "llvm/CodeGen/LiveStacks.h"
 #include "llvm/CodeGen/MachineFunctionPass.h"
 #include <queue>
 using namespace llvm;
 
 #define DEBUG_TYPE "riscv-insert-vsetvli"
 #define RISCV_INSERT_VSETVLI_NAME "RISC-V Insert VSETVLI pass"
-#define RISCV_COALESCE_VSETVLI_NAME "RISC-V Coalesce VSETVLI pass"
 
 STATISTIC(NumInsertedVSETVL, "Number of VSETVL inst inserted");
-STATISTIC(NumCoalescedVSETVL, "Number of VSETVL inst coalesced");
+STATISTIC(NumRemovedVSETVL, "Number of VSETVL inst removed");
 
 static cl::opt<bool> DisableInsertVSETVLPHIOpt(
     "riscv-disable-insert-vsetvl-phi-opt", cl::init(false), cl::Hidden,
@@ -193,11 +190,6 @@ static bool hasUndefinedMergeOp(const MachineInstr &MI,
   if (UseMO.getReg() == RISCV::NoRegister)
     return true;
 
-  if (UseMO.isUndef())
-    return true;
-  if (UseMO.getReg().isPhysical())
-    return false;
-
   if (MachineInstr *UseMI = MRI.getVRegDef(UseMO.getReg())) {
     if (UseMI->isImplicitDef())
       return true;
@@ -788,52 +780,18 @@ class RISCVInsertVSETVLI : public MachineFunctionPass {
                              VSETVLIInfo &Info) const;
   void computeIncomingVLVTYPE(const MachineBasicBlock &MBB);
   void emitVSETVLIs(MachineBasicBlock &MBB);
+  void doLocalPostpass(MachineBasicBlock &MBB);
   void doPRE(MachineBasicBlock &MBB);
   void insertReadVL(MachineBasicBlock &MBB);
 };
 
-class RISCVCoalesceVSETVLI : public MachineFunctionPass {
-public:
-  static char ID;
-  const RISCVSubtarget *ST;
-  const TargetInstrInfo *TII;
-  MachineRegisterInfo *MRI;
-  LiveIntervals *LIS;
-
-  RISCVCoalesceVSETVLI() : MachineFunctionPass(ID) {}
-  bool runOnMachineFunction(MachineFunction &MF) override;
-
-  void getAnalysisUsage(AnalysisUsage &AU) const override {
-    AU.setPreservesCFG();
-
-    AU.addRequired<LiveIntervals>();
-    AU.addPreserved<LiveIntervals>();
-    AU.addRequired<SlotIndexes>();
-    AU.addPreserved<SlotIndexes>();
-    AU.addPreserved<LiveDebugVariables>();
-    AU.addPreserved<LiveStacks>();
-
-    MachineFunctionPass::getAnalysisUsage(AU);
-  }
-
-  StringRef getPassName() const override { return RISCV_COALESCE_VSETVLI_NAME; }
-
-private:
-  bool coalesceVSETVLIs(MachineBasicBlock &MBB);
-};
-
 } // end anonymous namespace
 
 char RISCVInsertVSETVLI::ID = 0;
 
 INITIALIZE_PASS(RISCVInsertVSETVLI, DEBUG_TYPE, RISCV_INSERT_VSETVLI_NAME,
                 false, false)
 
-char RISCVCoalesceVSETVLI::ID = 0;
-
-INITIALIZE_PASS(RISCVCoalesceVSETVLI, "riscv-coalesce-vsetvli",
-                RISCV_COALESCE_VSETVLI_NAME, false, false)
-
 // Return a VSETVLIInfo representing the changes made by this VSETVLI or
 // VSETIVLI instruction.
 static VSETVLIInfo getInfoForVSETVLI(const MachineInstr &MI) {
@@ -1557,12 +1515,12 @@ static bool canMutatePriorConfig(const MachineInstr &PrevMI,
 
     auto &AVL = MI.getOperand(1);
     auto &PrevAVL = PrevMI.getOperand(1);
+    assert(MRI.isSSA());
 
     // If the AVL is a register, we need to make sure MI's AVL dominates PrevMI.
     // For now just check that PrevMI uses the same virtual register.
     if (AVL.isReg() && AVL.getReg() != RISCV::X0 &&
-        (!MRI.hasOneDef(AVL.getReg()) || !PrevAVL.isReg() ||
-         PrevAVL.getReg() != AVL.getReg()))
+        (!PrevAVL.isReg() || PrevAVL.getReg() != AVL.getReg()))
       return false;
   }
 
@@ -1572,7 +1530,7 @@ static bool canMutatePriorConfig(const MachineInstr &PrevMI,
   return areCompatibleVTYPEs(PriorVType, VType, Used);
 }
 
-bool RISCVCoalesceVSETVLI::coalesceVSETVLIs(MachineBasicBlock &MBB) {
+void RISCVInsertVSETVLI::doLocalPostpass(MachineBasicBlock &MBB) {
   MachineInstr *NextMI = nullptr;
   // We can have arbitrary code in successors, so VL and VTYPE
   // must be considered demanded.
@@ -1605,49 +1563,20 @@ bool RISCVCoalesceVSETVLI::coalesceVSETVLIs(MachineBasicBlock &MBB) {
 
       if (canMutatePriorConfig(MI, *NextMI, Used, *MRI)) {
         if (!isVLPreservingConfig(*NextMI)) {
-          Register DefReg = NextMI->getOperand(0).getReg();
-
-          MI.getOperand(0).setReg(DefReg);
+          MI.getOperand(0).setReg(NextMI->getOperand(0).getReg());
           MI.getOperand(0).setIsDead(false);
-
-          // The def of DefReg moved to MI, so extend the LiveInterval up to
-          // it.
-          if (DefReg.isVirtual()) {
-            LiveInterval &DefLI = LIS->getInterval(DefReg);
-            SlotIndex MISlot = LIS->getInstructionIndex(MI).getRegSlot();
-            VNInfo *DefVNI = DefLI.getVNInfoAt(DefLI.beginIndex());
-            LiveInterval::Segment S(MISlot, DefLI.beginIndex(), DefVNI);
-            DefLI.addSegment(S);
-            DefVNI->def = MISlot;
-            // Mark DefLI as spillable if it was previously unspillable
-            DefLI.setWeight(0);
-
-            // DefReg may have had no uses, in which case we need to shrink
-            // the LiveInterval up to MI.
-            LIS->shrinkToUses(&DefLI);
-          }
-
           Register OldVLReg;
           if (MI.getOperand(1).isReg())
             OldVLReg = MI.getOperand(1).getReg();
           if (NextMI->getOperand(1).isImm())
             MI.getOperand(1).ChangeToImmediate(NextMI->getOperand(1).getImm());
           else
             MI.getOperand(1).ChangeToRegister(NextMI->getOperand(1).getReg(), false);
-
-          // Clear NextMI's AVL early so we're not counting it as a use.
-          if (NextMI->getOperand(1).isReg())
-            NextMI->getOperand(1).setReg(RISCV::NoRegister);
-
           if (OldVLReg) {
             MachineInstr *VLOpDef = MRI->getUniqueVRegDef(OldVLReg);
             if (VLOpDef && TII->isAddImmediate(*VLOpDef, OldVLReg) &&
                 MRI->use_nodbg_empty(OldVLReg))
               VLOpDef->eraseFromParent();
-
-            // NextMI no longer uses OldVLReg so shrink its LiveInterval.
-            if (OldVLReg.isVirtual())
-              LIS->shrinkToUses(&LIS->getInterval(OldVLReg));
           }
           MI.setDesc(NextMI->getDesc());
         }
@@ -1660,13 +1589,9 @@ bool RISCVCoalesceVSETVLI::coalesceVSETVLIs(MachineBasicBlock &MBB) {
     Used = getDemanded(MI, MRI, ST);
   }
 
-  NumCoalescedVSETVL += ToDelete.size();
-  for (auto *MI : ToDelete) {
-    LIS->RemoveMachineInstrFromMaps(*MI);
+  NumRemovedVSETVL += ToDelete.size();
+  for (auto *MI : ToDelete)
     MI->eraseFromParent();
-  }
-
-  return !ToDelete.empty();
 }
 
 void RISCVInsertVSETVLI::insertReadVL(MachineBasicBlock &MBB) {
@@ -1741,6 +1666,15 @@ bool RISCVInsertVSETVLI::runOnMachineFunction(MachineFunction &MF) {
   for (MachineBasicBlock &MBB : MF)
     emitVSETVLIs(MBB);
 
+  // Now that all vsetvlis are explicit, go through and do block local
+  // DSE and peephole based demanded fields based transforms.  Note that
+  // this *must* be done outside the main dataflow so long as we allow
+  // any cross block analysis within the dataflow.  We can't have both
+  // demanded fields based mutation and non-local analysis in the
+  // dataflow at the same time without introducing inconsistencies.
+  for (MachineBasicBlock &MBB : MF)
+    doLocalPostpass(MBB);
+
   // Insert PseudoReadVL after VLEFF/VLSEGFF and replace it with the vl output
   // of VLEFF/VLSEGFF.
   for (MachineBasicBlock &MBB : MF)
@@ -1754,29 +1688,3 @@ bool RISCVInsertVSETVLI::runOnMachineFunction(MachineFunction &MF) {
 FunctionPass *llvm::createRISCVInsertVSETVLIPass() {
   return new RISCVInsertVSETVLI();
 }
-
-// Now that all vsetvlis are explicit, go through and do block local
-// DSE and peephole based demanded fields based transforms.  Note that
-// this *must* be done outside the main dataflow so long as we allow
-// any cross block analysis within the dataflow.  We can't have both
-// demanded fields based mutation and non-local analysis in the
-// dataflow at the same time without introducing inconsistencies.
-bool RISCVCoalesceVSETVLI::runOnMachineFunction(MachineFunction &MF) {
-  // Skip if the vector extension is not enabled.
-  ST = &MF.getSubtarget<RISCVSubtarget>();
-  if (!ST->hasVInstructions())
-    return false;
-  TII = ST->getInstrInfo();
-  MRI = &MF.getRegInfo();
-  LIS = &getAnalysis<LiveIntervals>();
-
-  bool Changed = false;
-  for (MachineBasicBlock &MBB : MF)
-    Changed |= coalesceVSETVLIs(MBB);
-
-  return Changed;
-}
-
-FunctionPass *llvm::createRISCVCoalesceVSETVLIPass() {
-  return new RISCVCoalesceVSETVLI();
-}

llvm/lib/Target/RISCV/RISCVTargetMachine.cpp

@@ -116,7 +116,6 @@ extern "C" LLVM_EXTERNAL_VISIBILITY void LLVMInitializeRISCVTarget() {
   initializeRISCVExpandPseudoPass(*PR);
   initializeRISCVFoldMasksPass(*PR);
   initializeRISCVInsertVSETVLIPass(*PR);
-  initializeRISCVCoalesceVSETVLIPass(*PR);
   initializeRISCVInsertReadWriteCSRPass(*PR);
   initializeRISCVInsertWriteVXRMPass(*PR);
   initializeRISCVDAGToDAGISelPass(*PR);
@@ -389,14 +388,12 @@ FunctionPass *RISCVPassConfig::createRVVRegAllocPass(bool Optimized) {
 
 bool RISCVPassConfig::addRegAssignAndRewriteFast() {
   addPass(createRVVRegAllocPass(false));
-  addPass(createRISCVCoalesceVSETVLIPass());
   return TargetPassConfig::addRegAssignAndRewriteFast();
 }
 
 bool RISCVPassConfig::addRegAssignAndRewriteOptimized() {
   addPass(createRVVRegAllocPass(true));
   addPass(createVirtRegRewriter(false));
-  addPass(createRISCVCoalesceVSETVLIPass());
   return TargetPassConfig::addRegAssignAndRewriteOptimized();
 }
 

llvm/test/CodeGen/RISCV/O0-pipeline.ll

@@ -47,10 +47,6 @@
 ; CHECK-NEXT:       Eliminate PHI nodes for register allocation
 ; CHECK-NEXT:       Two-Address instruction pass
 ; CHECK-NEXT:       Fast Register Allocator
-; CHECK-NEXT:       MachineDominator Tree Construction
-; CHECK-NEXT:       Slot index numbering
-; CHECK-NEXT:       Live Interval Analysis
-; CHECK-NEXT:       RISC-V Coalesce VSETVLI pass
 ; CHECK-NEXT:       Fast Register Allocator
 ; CHECK-NEXT:       Remove Redundant DEBUG_VALUE analysis
 ; CHECK-NEXT:       Fixup Statepoint Caller Saved

llvm/test/CodeGen/RISCV/O3-pipeline.ll

@@ -143,7 +143,6 @@
 ; CHECK-NEXT:       Machine Optimization Remark Emitter
 ; CHECK-NEXT:       Greedy Register Allocator
 ; CHECK-NEXT:       Virtual Register Rewriter
-; CHECK-NEXT:       RISC-V Coalesce VSETVLI pass
 ; CHECK-NEXT:       Virtual Register Map
 ; CHECK-NEXT:       Live Register Matrix
 ; CHECK-NEXT:       Greedy Register Allocator

llvm/test/CodeGen/RISCV/rvv/fixed-vectors-fp-buildvec.ll

@@ -1407,8 +1407,8 @@ define <8 x float> @buildvec_v8f32_zvl256(float %e0, float %e1, float %e2, float
 ; CHECK-NEXT:    vfmv.v.f v8, fa4
 ; CHECK-NEXT:    vfslide1down.vf v8, v8, fa5
 ; CHECK-NEXT:    vfslide1down.vf v8, v8, fa6
-; CHECK-NEXT:    vfslide1down.vf v8, v8, fa7
 ; CHECK-NEXT:    vmv.v.i v0, 15
+; CHECK-NEXT:    vfslide1down.vf v8, v8, fa7
 ; CHECK-NEXT:    vslidedown.vi v8, v9, 4, v0.t
 ; CHECK-NEXT:    ret
   %v0 = insertelement <8 x float> poison, float %e0, i64 0
@@ -1458,8 +1458,8 @@ define <8 x double> @buildvec_v8f64_zvl512(double %e0, double %e1, double %e2, d
 ; CHECK-NEXT:    vfmv.v.f v8, fa4
 ; CHECK-NEXT:    vfslide1down.vf v8, v8, fa5
 ; CHECK-NEXT:    vfslide1down.vf v8, v8, fa6
-; CHECK-NEXT:    vfslide1down.vf v8, v8, fa7
 ; CHECK-NEXT:    vmv.v.i v0, 15
+; CHECK-NEXT:    vfslide1down.vf v8, v8, fa7
 ; CHECK-NEXT:    vslidedown.vi v8, v9, 4, v0.t
 ; CHECK-NEXT:    ret
   %v0 = insertelement <8 x double> poison, double %e0, i64 0

llvm/test/CodeGen/RISCV/rvv/fixed-vectors-fp-interleave.ll

@@ -57,8 +57,8 @@ define <4 x double> @interleave_v2f64(<2 x double> %x, <2 x double> %y) {
 ; RV32-V512-NEXT:    vid.v v10
 ; RV32-V512-NEXT:    vsrl.vi v11, v10, 1
 ; RV32-V512-NEXT:    vsetvli zero, zero, e64, m1, ta, mu
-; RV32-V512-NEXT:    vrgatherei16.vv v10, v8, v11
 ; RV32-V512-NEXT:    vmv.v.i v0, 10
+; RV32-V512-NEXT:    vrgatherei16.vv v10, v8, v11
 ; RV32-V512-NEXT:    vrgatherei16.vv v10, v9, v11, v0.t
 ; RV32-V512-NEXT:    vmv.v.v v8, v10
 ; RV32-V512-NEXT:    ret
@@ -68,8 +68,8 @@ define <4 x double> @interleave_v2f64(<2 x double> %x, <2 x double> %y) {
 ; RV64-V512-NEXT:    vsetivli zero, 4, e64, m1, ta, mu
 ; RV64-V512-NEXT:    vid.v v10
 ; RV64-V512-NEXT:    vsrl.vi v11, v10, 1
-; RV64-V512-NEXT:    vrgather.vv v10, v8, v11
 ; RV64-V512-NEXT:    vmv.v.i v0, 10
+; RV64-V512-NEXT:    vrgather.vv v10, v8, v11
 ; RV64-V512-NEXT:    vrgather.vv v10, v9, v11, v0.t
 ; RV64-V512-NEXT:    vmv.v.v v8, v10
 ; RV64-V512-NEXT:    ret

llvm/test/CodeGen/RISCV/rvv/fixed-vectors-fp2i-sat.ll

@@ -395,8 +395,8 @@ define void @fp2si_v8f64_v8i8(ptr %x, ptr %y) {
 ; RV32-NEXT:    fmin.d fa5, fa5, fa4
 ; RV32-NEXT:    fcvt.w.d a2, fa5, rtz
 ; RV32-NEXT:    and a0, a0, a2
-; RV32-NEXT:    vslide1down.vx v9, v9, a0
 ; RV32-NEXT:    vmv.v.i v0, 15
+; RV32-NEXT:    vslide1down.vx v9, v9, a0
 ; RV32-NEXT:    vslidedown.vi v9, v8, 4, v0.t
 ; RV32-NEXT:    vse8.v v9, (a1)
 ; RV32-NEXT:    addi sp, s0, -128
@@ -496,8 +496,8 @@ define void @fp2si_v8f64_v8i8(ptr %x, ptr %y) {
 ; RV64-NEXT:    fmin.d fa5, fa5, fa4
 ; RV64-NEXT:    fcvt.l.d a2, fa5, rtz
 ; RV64-NEXT:    and a0, a0, a2
-; RV64-NEXT:    vslide1down.vx v9, v9, a0
 ; RV64-NEXT:    vmv.v.i v0, 15
+; RV64-NEXT:    vslide1down.vx v9, v9, a0
 ; RV64-NEXT:    vslidedown.vi v9, v8, 4, v0.t
 ; RV64-NEXT:    vse8.v v9, (a1)
 ; RV64-NEXT:    addi sp, s0, -128
@@ -580,8 +580,8 @@ define void @fp2ui_v8f64_v8i8(ptr %x, ptr %y) {
 ; RV32-NEXT:    fmax.d fa4, fa4, fa3
 ; RV32-NEXT:    fmin.d fa5, fa4, fa5
 ; RV32-NEXT:    fcvt.wu.d a0, fa5, rtz
-; RV32-NEXT:    vslide1down.vx v9, v9, a0
 ; RV32-NEXT:    vmv.v.i v0, 15
+; RV32-NEXT:    vslide1down.vx v9, v9, a0
 ; RV32-NEXT:    vslidedown.vi v9, v8, 4, v0.t
 ; RV32-NEXT:    vse8.v v9, (a1)
 ; RV32-NEXT:    addi sp, s0, -128
@@ -656,8 +656,8 @@ define void @fp2ui_v8f64_v8i8(ptr %x, ptr %y) {
 ; RV64-NEXT:    fmax.d fa4, fa4, fa3
 ; RV64-NEXT:    fmin.d fa5, fa4, fa5
 ; RV64-NEXT:    fcvt.lu.d a0, fa5, rtz
-; RV64-NEXT:    vslide1down.vx v9, v9, a0
 ; RV64-NEXT:    vmv.v.i v0, 15
+; RV64-NEXT:    vslide1down.vx v9, v9, a0
 ; RV64-NEXT:    vslidedown.vi v9, v8, 4, v0.t
 ; RV64-NEXT:    vse8.v v9, (a1)
 ; RV64-NEXT:    addi sp, s0, -128

llvm/test/CodeGen/RISCV/rvv/fixed-vectors-int-interleave.ll

@@ -70,8 +70,8 @@ define <4 x i64> @interleave_v2i64(<2 x i64> %x, <2 x i64> %y) {
 ; RV32-V512-NEXT:    vid.v v10
 ; RV32-V512-NEXT:    vsrl.vi v11, v10, 1
 ; RV32-V512-NEXT:    vsetvli zero, zero, e64, m1, ta, mu
-; RV32-V512-NEXT:    vrgatherei16.vv v10, v8, v11
 ; RV32-V512-NEXT:    vmv.v.i v0, 10
+; RV32-V512-NEXT:    vrgatherei16.vv v10, v8, v11
 ; RV32-V512-NEXT:    vrgatherei16.vv v10, v9, v11, v0.t
 ; RV32-V512-NEXT:    vmv.v.v v8, v10
 ; RV32-V512-NEXT:    ret
@@ -81,8 +81,8 @@ define <4 x i64> @interleave_v2i64(<2 x i64> %x, <2 x i64> %y) {
 ; RV64-V512-NEXT:    vsetivli zero, 4, e64, m1, ta, mu
 ; RV64-V512-NEXT:    vid.v v10
 ; RV64-V512-NEXT:    vsrl.vi v11, v10, 1
-; RV64-V512-NEXT:    vrgather.vv v10, v8, v11
 ; RV64-V512-NEXT:    vmv.v.i v0, 10
+; RV64-V512-NEXT:    vrgather.vv v10, v8, v11
 ; RV64-V512-NEXT:    vrgather.vv v10, v9, v11, v0.t
 ; RV64-V512-NEXT:    vmv.v.v v8, v10
 ; RV64-V512-NEXT:    ret
@@ -195,8 +195,8 @@ define <4 x i32> @interleave_v4i32_offset_1(<4 x i32> %x, <4 x i32> %y) {
 ; V128-NEXT:    vsetivli zero, 4, e32, m1, ta, mu
 ; V128-NEXT:    vid.v v8
 ; V128-NEXT:    vsrl.vi v8, v8, 1
-; V128-NEXT:    vadd.vi v8, v8, 1
 ; V128-NEXT:    vmv.v.i v0, 10
+; V128-NEXT:    vadd.vi v8, v8, 1
 ; V128-NEXT:    vrgather.vv v10, v9, v8, v0.t
 ; V128-NEXT:    vmv.v.v v8, v10
 ; V128-NEXT:    ret
@@ -210,8 +210,8 @@ define <4 x i32> @interleave_v4i32_offset_1(<4 x i32> %x, <4 x i32> %y) {
 ; V512-NEXT:    vsetivli zero, 4, e32, mf2, ta, mu
 ; V512-NEXT:    vid.v v8
 ; V512-NEXT:    vsrl.vi v8, v8, 1
-; V512-NEXT:    vadd.vi v8, v8, 1
 ; V512-NEXT:    vmv.v.i v0, 10
+; V512-NEXT:    vadd.vi v8, v8, 1
 ; V512-NEXT:    vrgather.vv v10, v9, v8, v0.t
 ; V512-NEXT:    vmv1r.v v8, v10
 ; V512-NEXT:    ret