R600/SI: Fix verifier error from a branch on IMPLICIT_DEF

[arsenm]

Summary

SIILowerI1Copies wasn't correctly handling this case.

[arsenm]

r222020

lib/Target/R600/SILowerI1Copies.cpp

for (I = MBB.begin(); I != MBB.end(); I = Next) {
       }
 
       if (MI.getOpcode() == AMDGPU::V_XOR_I1) {
         I1Defs.push_back(MI.getOperand(0).getReg());
         MI.setDesc(TII->get(AMDGPU::V_XOR_B32_e32));
         continue;
       }
 
+      if (MI.getOpcode() == AMDGPU::IMPLICIT_DEF) {
+        unsigned Reg = MI.getOperand(0).getReg();
+        const TargetRegisterClass *RC = MRI.getRegClass(Reg);
+        if (RC == &AMDGPU::VReg_1RegClass)
+          MRI.setRegClass(Reg, &AMDGPU::SReg_64RegClass);
+        continue;
+      }
+
       if (MI.getOpcode() != AMDGPU::COPY ||
           !TargetRegisterInfo::isVirtualRegister(MI.getOperand(0).getReg()) ||
           !TargetRegisterInfo::isVirtualRegister(MI.getOperand(1).getReg()))
         continue;
 
 
       const TargetRegisterClass *DstRC =
           MRI.getRegClass(MI.getOperand(0).getReg());

test/CodeGen/R600/i1-copy-implicit-def.ll

+; RUN: llc -march=r600 -mcpu=SI -verify-machineinstrs < %s | FileCheck -check-prefix=SI %s
+
+
+; SILowerI1Copies was not handling IMPLICIT_DEF
+; SI-LABEL: @br_implicit_def
+; SI: BB#0:
+; SI-NEXT: S_AND_SAVEEXEC_B64
+; SI-NEXT: S_XOR_B64
+; SI-NEXT: BB#1:
+define void @br_implicit_def(i32 addrspace(1)* %out, i32 %arg) #0 {
+bb:
+  br i1 undef, label %bb1, label %bb2
+
+bb1:
+  store volatile i32 123, i32 addrspace(1)* %out
+  ret void
+
+bb2:
+  ret void
+}
+
+
+attributes #0 = { nounwind }

test/CodeGen/R600/v-cmp-vreg1-src-error.ll

-; XFAIL: *
-; RUN: llc -march=r600 -mcpu=SI -verify-machineinstrs < %s
-
-define void @init_data_cost_reduce_0(i32 %arg) #0 {
-bb:
-  br i1 undef, label %bb1, label %bb2
-
-bb1:                                              ; preds = %bb
-  br label %bb2
-
-bb2:                                              ; preds = %bb1, %bb
-  br i1 undef, label %bb3, label %bb4
-
-bb3:                                              ; preds = %bb2
-  %tmp = mul i32 undef, %arg
-  br label %bb4
-
-bb4:                                              ; preds = %bb3, %bb2
-  unreachable
-}
-
-attributes #0 = { nounwind }