[SystemZ] Make sure of correct regclasses in insertSelect()

Since LOCR only accepts GR32 virtual registers, its operands must be copied
into this regclass in insertSelect(), when an LOCR is built. Otherwise, the
case where the source operand was GRX32 will produce invalid IR.

Review: Ulrich Weigand
llvm-svn: 299220

diff --git a/llvm/lib/Target/SystemZ/SystemZInstrInfo.cpp b/llvm/lib/Target/SystemZ/SystemZInstrInfo.cpp
index f3eed05..c8ff955 100644 (file)
--- a/llvm/lib/Target/SystemZ/SystemZInstrInfo.cpp
+++ b/llvm/lib/Target/SystemZ/SystemZInstrInfo.cpp
@@ -679,6 +679,12 @@ void SystemZInstrInfo::insertSelect(MachineBasicBlock &MBB,
     else {
       Opc = SystemZ::LOCR;
       MRI.constrainRegClass(DstReg, &SystemZ::GR32BitRegClass);
+      unsigned TReg = MRI.createVirtualRegister(&SystemZ::GR32BitRegClass);
+      unsigned FReg = MRI.createVirtualRegister(&SystemZ::GR32BitRegClass);
+      BuildMI(MBB, I, DL, get(TargetOpcode::COPY), TReg).addReg(TrueReg);
+      BuildMI(MBB, I, DL, get(TargetOpcode::COPY), FReg).addReg(FalseReg);
+      TrueReg = TReg;
+      FalseReg = FReg;
     }
   } else if (SystemZ::GR64BitRegClass.hasSubClassEq(RC))
     Opc = SystemZ::LOCGR;

diff --git a/llvm/test/CodeGen/SystemZ/locr-legal-regclass.ll b/llvm/test/CodeGen/SystemZ/locr-legal-regclass.ll
new file mode 100644 (file)
index 0000000..1f79243
--- /dev/null
+++ b/llvm/test/CodeGen/SystemZ/locr-legal-regclass.ll
@@ -0,0 +1,20 @@
+; RUN: llc < %s -mtriple=s390x-linux-gnu -mcpu=zEC12 -verify-machineinstrs | FileCheck %s
+;
+; Test that early if conversion produces LOCR with operands of the right
+; register classes.
+
+define void @autogen_SD4739(i8*) {
+; CHECK-NOT: Expected a GR32Bit register, but got a GRX32Bit register
+BB:
+  %L34 = load i8, i8* %0
+  %Cmp56 = icmp sgt i8 undef, %L34
+  br label %CF246
+
+CF246:                                            ; preds = %CF246, %BB
+  %Sl163 = select i1 %Cmp56, i8 %L34, i8 undef
+  br i1 undef, label %CF246, label %CF248
+
+CF248:                                            ; preds = %CF248, %CF246
+  store i8 %Sl163, i8* %0
+  br label %CF248
+}