[SystemZ] Drop regstate of SELRMux operand in selectSLRMux().

llvm/lib/Target/SystemZ/SystemZPostRewrite.cpp

@@ -101,8 +101,10 @@ void SystemZPostRewrite::selectSELRMux(MachineBasicBlock &MBB,
                                        unsigned LowOpcode,
                                        unsigned HighOpcode) {
   Register DestReg = MBBI->getOperand(0).getReg();
-  Register Src1Reg = MBBI->getOperand(1).getReg();
-  Register Src2Reg = MBBI->getOperand(2).getReg();
+  MachineOperand &Src1MO = MBBI->getOperand(1);
+  MachineOperand &Src2MO = MBBI->getOperand(2);
+  Register Src1Reg = Src1MO.getReg();
+  Register Src2Reg = Src2MO.getReg();
   bool DestIsHigh = SystemZ::isHighReg(DestReg);
   bool Src1IsHigh = SystemZ::isHighReg(Src1Reg);
   bool Src2IsHigh = SystemZ::isHighReg(Src2Reg);
@@ -114,7 +116,7 @@ void SystemZPostRewrite::selectSELRMux(MachineBasicBlock &MBB,
   if (Src1Reg == Src2Reg) {
     BuildMI(*MBBI->getParent(), MBBI, MBBI->getDebugLoc(),
             TII->get(SystemZ::COPY), DestReg)
-        .addReg(MBBI->getOperand(1).getReg(), getRegState(MBBI->getOperand(1)));
+        .addReg(Src1Reg, getRegState(Src1MO) & getRegState(Src2MO));
     MBBI->eraseFromParent();
     return;
   }
@@ -126,15 +128,15 @@ void SystemZPostRewrite::selectSELRMux(MachineBasicBlock &MBB,
     if (DestIsHigh != Src1IsHigh) {
       BuildMI(*MBBI->getParent(), MBBI, MBBI->getDebugLoc(),
               TII->get(SystemZ::COPY), DestReg)
-        .addReg(MBBI->getOperand(1).getReg(), getRegState(MBBI->getOperand(1)));
-      MBBI->getOperand(1).setReg(DestReg);
+          .addReg(Src1Reg, getRegState(Src1MO));
+      Src1MO.setReg(DestReg);
       Src1Reg = DestReg;
       Src1IsHigh = DestIsHigh;
     } else if (DestIsHigh != Src2IsHigh) {
       BuildMI(*MBBI->getParent(), MBBI, MBBI->getDebugLoc(),
               TII->get(SystemZ::COPY), DestReg)
-        .addReg(MBBI->getOperand(2).getReg(), getRegState(MBBI->getOperand(2)));
-      MBBI->getOperand(2).setReg(DestReg);
+          .addReg(Src2Reg, getRegState(Src2MO));
+      Src2MO.setReg(DestReg);
       Src2Reg = DestReg;
       Src2IsHigh = DestIsHigh;
     }

llvm/test/CodeGen/SystemZ/cond-move-10.mir

@@ -5,7 +5,7 @@
 # CHECK:      name: fun0
 # CHECK:      renamable $r1l = AHIMuxK killed renamable $r1l, -1, implicit-def dead $cc
 # CHECK-NEXT: CHIMux renamable $r5h, 9, implicit-def $cc
-# CHECK-NEXT: $r14h = COPY killed renamable $r1l
+# CHECK-NEXT: $r14h = COPY renamable $r1l
 ---
 name:            fun0
 tracksRegLiveness: true

llvm/test/CodeGen/SystemZ/cond-move-11.mir

@@ -0,0 +1,43 @@
+# RUN: llc -o - %s -mtriple=s390x-linux-gnu -mcpu=z15 -start-before=systemz-post-rewrite \
+# RUN:   -stop-after=machine-cp -verify-machineinstrs 2>&1 | FileCheck %s
+
+# The chained SELRMux:es both has two operands with the same register but
+# where one of the operands have been marked as undef (resulting from
+# early-ifcvt). Check that the resulting COPY after machine-cp is from $r0l
+# to $r2l.
+
+# CHECK:      name: fun0
+# CHECK:      $r2l = COPY $r0l
+--- |
+
+  @Res = global i32 0, align 4
+  @Z = global i32 0, align 4
+  define signext i32 @fun0() { ret i32 0 }
+...
+---
+name:            fun0
+tracksRegLiveness: true
+body:             |
+  bb.0:
+    successors: %bb.1(0x80000000)
+
+    renamable $r0l = LRL @Z :: (dereferenceable load (s32) from @Z)
+    renamable $r1l = LHIMux 1
+
+  bb.1:
+    successors: %bb.1(0x7c000000), %bb.2(0x04000000)
+    liveins: $r0l, $r1l
+
+    CHIMux renamable $r1l, 0, implicit-def $cc
+    renamable $r2l = SELRMux undef renamable $r0l, renamable $r0l, 14, 6, implicit $cc
+    renamable $r2l = SELRMux undef renamable $r2l, killed renamable $r2l, 14, 6, implicit $cc
+    BRC 14, 8, %bb.1, implicit killed $cc
+    J %bb.2
+
+  bb.2:
+    liveins: $r2l
+
+    STRL renamable $r2l, @Res :: (store (s32) into @Res)
+    renamable $r2d = LGFR killed renamable $r2l
+    Return implicit $r2d
+...