Quick: Fix DCE to rename SSA regs for degenerate Phis.
If we're inserting a new Phi and all its inputs are the same
SSA reg (for example, we allow a single-input Phi), some
subsequent insn may actually refer to that reg, so we need
to rename it to keep the graph in a consistent state.
Change-Id: Ic6a1907c3138f4a7d3b13f9e58e9107ca2d92f17
diff --git a/compiler/dex/gvn_dead_code_elimination_test.cc b/compiler/dex/gvn_dead_code_elimination_test.cc
index f9f0882..efb32bb 100644
--- a/compiler/dex/gvn_dead_code_elimination_test.cc
+++ b/compiler/dex/gvn_dead_code_elimination_test.cc
@@ -1629,6 +1629,52 @@
}
TEST_F(GvnDeadCodeEliminationTestDiamond, CreatePhi2) {
+ static const MIRDef mirs[] = {
+ DEF_CONST(3, Instruction::CONST, 0u, 1000),
+ DEF_MOVE(4, Instruction::MOVE, 1u, 0u),
+ DEF_CONST(4, Instruction::CONST, 2u, 1000),
+ };
+
+ static const int32_t sreg_to_vreg_map[] = { 0, 1, 0 };
+ PrepareSRegToVRegMap(sreg_to_vreg_map);
+
+ PrepareMIRs(mirs);
+ PerformGVN_DCE();
+
+ ASSERT_EQ(arraysize(mirs), value_names_.size());
+ EXPECT_EQ(value_names_[0], value_names_[1]);
+ EXPECT_EQ(value_names_[0], value_names_[2]);
+
+ static const bool eliminated[] = {
+ false, false, true,
+ };
+ static_assert(arraysize(eliminated) == arraysize(mirs), "array size mismatch");
+ for (size_t i = 0; i != arraysize(eliminated); ++i) {
+ bool actually_eliminated = (static_cast<int>(mirs_[i].dalvikInsn.opcode) == kMirOpNop);
+ EXPECT_EQ(eliminated[i], actually_eliminated) << i;
+ }
+ // Check that we've created a single-input Phi to replace the CONST 3u.
+ BasicBlock* bb4 = cu_.mir_graph->GetBasicBlock(4);
+ MIR* phi = bb4->first_mir_insn;
+ ASSERT_TRUE(phi != nullptr);
+ ASSERT_EQ(kMirOpPhi, static_cast<int>(phi->dalvikInsn.opcode));
+ ASSERT_EQ(1, phi->ssa_rep->num_uses);
+ EXPECT_EQ(0, phi->ssa_rep->uses[0]);
+ ASSERT_EQ(1, phi->ssa_rep->num_defs);
+ EXPECT_EQ(2, phi->ssa_rep->defs[0]);
+ EXPECT_EQ(0u, phi->dalvikInsn.vA);
+ MIR* move = phi->next;
+ ASSERT_TRUE(move != nullptr);
+ ASSERT_EQ(Instruction::MOVE, move->dalvikInsn.opcode);
+ ASSERT_EQ(1, move->ssa_rep->num_uses);
+ EXPECT_EQ(2, move->ssa_rep->uses[0]);
+ ASSERT_EQ(1, move->ssa_rep->num_defs);
+ EXPECT_EQ(1, move->ssa_rep->defs[0]);
+ EXPECT_EQ(1u, move->dalvikInsn.vA);
+ EXPECT_EQ(0u, move->dalvikInsn.vB);
+}
+
+TEST_F(GvnDeadCodeEliminationTestDiamond, CreatePhi3) {
static const IFieldDef ifields[] = {
{ 0u, 1u, 0u, false, kDexMemAccessWord },
};