[RISCV] Fix crash when trying to remove segment

llvm/lib/Target/RISCV/RISCVInsertVSETVLI.cpp

@@ -1768,8 +1768,9 @@ void RISCVInsertVSETVLI::insertReadVL(MachineBasicBlock &MBB) {
           SlotIndex NewDefSI =
               LIS->InsertMachineInstrInMaps(*ReadVLMI).getRegSlot();
           LiveInterval &DefLI = LIS->getInterval(VLOutput);
-          VNInfo *DefVNI = DefLI.getVNInfoAt(DefLI.beginIndex());
-          DefLI.removeSegment(DefLI.beginIndex(), NewDefSI);
+          LiveRange::Segment *DefSeg = DefLI.getSegmentContaining(NewDefSI);
+          VNInfo *DefVNI = DefLI.getVNInfoAt(DefSeg->start);
+          DefLI.removeSegment(DefSeg->start, NewDefSI);
           DefVNI->def = NewDefSI;
         }
       }

llvm/test/CodeGen/RISCV/rvv/vsetvli-insert.ll

@@ -722,3 +722,35 @@ define i64 @avl_undef2() {
   %1 = tail call i64 @llvm.riscv.vsetvli(i64 poison, i64 2, i64 7)
   ret i64 %1
 }
+
+define i64 @vsetvli_vleff(ptr %s, i64 %evl) {
+; CHECK-LABEL: vsetvli_vleff:
+; CHECK:       # %bb.0: # %entry
+; CHECK-NEXT:    vsetvli a3, zero, e16, m1, ta, ma
+; CHECK-NEXT:    vmv.v.i v8, 0
+; CHECK-NEXT:  .LBB37_1: # %while.body
+; CHECK-NEXT:    # =>This Inner Loop Header: Depth=1
+; CHECK-NEXT:    vsetvli zero, a1, e16, m1, tu, ma
+; CHECK-NEXT:    vmv1r.v v9, v8
+; CHECK-NEXT:    vle16ff.v v9, (a0)
+; CHECK-NEXT:    csrr a2, vl
+; CHECK-NEXT:    beqz a2, .LBB37_1
+; CHECK-NEXT:  # %bb.2: # %while.end
+; CHECK-NEXT:    li a0, 0
+; CHECK-NEXT:    ret
+entry:
+  br label %while.cond
+
+while.cond:
+  %new_vl.0 = phi i64 [ 0, %entry ], [ %1, %while.body ]
+  %cmp = icmp eq i64 %new_vl.0, 0
+  br i1 %cmp, label %while.body, label %while.end
+
+while.body:
+  %0 = tail call { <vscale x 4 x i16>, i64 } @llvm.riscv.vleff.nxv4i16.i64(<vscale x 4 x i16> zeroinitializer, ptr %s, i64 %evl)
+  %1 = extractvalue { <vscale x 4 x i16>, i64 } %0, 1
+  br label %while.cond
+
+while.end:
+  ret i64 0
+}

llvm/test/CodeGen/RISCV/rvv/vsetvli-insert.mir

@@ -100,6 +100,10 @@
     ret void
   }
 
+  define void @vsetvli_vleff() {
+    ret void
+  }
+
   declare <vscale x 1 x i64> @llvm.riscv.vadd.nxv1i64.nxv1i64.i64(<vscale x 1 x i64>, <vscale x 1 x i64>, <vscale x 1 x i64>, i64) #1
 
   declare <vscale x 1 x i64> @llvm.riscv.vle.nxv1i64.i64(<vscale x 1 x i64>, ptr nocapture, i64) #4
@@ -622,3 +626,41 @@ body: |
     dead $x0 = PseudoVSETIVLI 1, 208, implicit-def $vl, implicit-def $vtype
     %v:vr = COPY $v8, implicit $vtype
     %x = PseudoVSETVLI %x, 208, implicit-def $vl, implicit-def $vtype
+...
+---
+name:            vsetvli_vleff
+tracksRegLiveness: true
+body:             |
+  ; CHECK-LABEL: name: vsetvli_vleff
+  ; CHECK: bb.0:
+  ; CHECK-NEXT:   successors: %bb.1(0x40000000), %bb.2(0x40000000)
+  ; CHECK-NEXT: {{  $}}
+  ; CHECK-NEXT:   %vl:gpr = COPY $x0
+  ; CHECK-NEXT:   BNE $x0, $x0, %bb.2
+  ; CHECK-NEXT:   PseudoBR %bb.1
+  ; CHECK-NEXT: {{  $}}
+  ; CHECK-NEXT: bb.1:
+  ; CHECK-NEXT:   successors: %bb.2(0x80000000)
+  ; CHECK-NEXT: {{  $}}
+  ; CHECK-NEXT:   dead $x0 = PseudoVSETIVLI 0, 200 /* e16, m1, ta, ma */, implicit-def $vl, implicit-def $vtype
+  ; CHECK-NEXT:   $noreg, $x0 = PseudoVLE16FF_V_M1 $noreg, $noreg, 0, 4 /* e16 */, 2 /* tu, ma */, implicit $vl, implicit $vtype, implicit-def $vl
+  ; CHECK-NEXT:   %vl:gpr = PseudoReadVL implicit $vl
+  ; CHECK-NEXT: {{  $}}
+  ; CHECK-NEXT: bb.2:
+  ; CHECK-NEXT:   $x10 = COPY %vl
+  ; CHECK-NEXT:   PseudoRET implicit killed $x10
+  bb.0:
+    successors: %bb.1(0x40000000), %bb.2(0x40000000)
+
+    %vl:gpr = COPY $x0
+    BNE $x0, $x0, %bb.2
+    PseudoBR %bb.1
+
+  bb.1:
+    successors: %bb.2(0x80000000)
+
+    $noreg, %vl:gpr = PseudoVLE16FF_V_M1 $noreg, $noreg, 0, 4 /* e16 */, 2 /* tu, ma */
+
+  bb.2:
+    $x10 = COPY %vl
+    PseudoRET implicit killed $x10