Fix a bug in SSA construction.
If a join block does not have an incoming value for a local
from a predecessor block, we should not create a phi. The
verifier has made sure the local is updated before any
following reads after this block.
Change-Id: Id2785efc73c9fb3224826fff2f4b4ad215905ff4
diff --git a/compiler/optimizing/ssa_test.cc b/compiler/optimizing/ssa_test.cc
index d104619..485ea27 100644
--- a/compiler/optimizing/ssa_test.cc
+++ b/compiler/optimizing/ssa_test.cc
@@ -459,4 +459,34 @@
TestCode(data, expected);
}
+TEST(SsaTest, LocalInIf) {
+ // Test that we do not create a phi in the join block when one predecessor
+ // does not update the local.
+ const char* expected =
+ "BasicBlock 0, succ: 1\n"
+ " 0: IntConstant 0 [3, 3]\n"
+ " 1: IntConstant 4\n"
+ " 2: Goto\n"
+ "BasicBlock 1, pred: 0, succ: 2, 5\n"
+ " 3: Equal(0, 0) [4]\n"
+ " 4: If(3)\n"
+ "BasicBlock 2, pred: 1, succ: 3\n"
+ " 5: Goto\n"
+ "BasicBlock 3, pred: 2, 5, succ: 4\n"
+ " 6: ReturnVoid\n"
+ "BasicBlock 4, pred: 3\n"
+ " 7: Exit\n"
+ // Synthesized block to avoid critical edge.
+ "BasicBlock 5, pred: 1, succ: 3\n"
+ " 8: Goto\n";
+
+ const uint16_t data[] = TWO_REGISTERS_CODE_ITEM(
+ Instruction::CONST_4 | 0 | 0,
+ Instruction::IF_EQ, 3,
+ Instruction::CONST_4 | 4 << 12 | 1 << 8,
+ Instruction::RETURN_VOID);
+
+ TestCode(data, expected);
+}
+
} // namespace art