return ::isGuaranteedNotToBeUndefOrPoison(V, AC, CtxI, DT, Depth, true);
}
-/// Return true if undefined behavior would provable be executed on the path to
+/// Return true if undefined behavior would provably be executed on the path to
/// OnPathTo if Root produced a posion result. Note that this doesn't say
/// anything about whether OnPathTo is actually executed or whether Root is
/// actually poison. This can be used to assess whether a new use of Root can
break;
}
}
+
+ // Special handling for select, which returns poison if its operand 0 is
+ // poison (handled in the loop above) *or* if both its true/false operands
+ // are poison (handled here).
+ if (I.getOpcode() == Instruction::Select &&
+ YieldsPoison.count(I.getOperand(1)) &&
+ YieldsPoison.count(I.getOperand(2))) {
+ YieldsPoison.insert(&I);
+ }
}
BB = BB->getSingleSuccessor();
EXPECT_EQ(programUndefinedIfPoison(A), true);
}
+TEST_F(ValueTrackingTest, programUndefinedIfPoisonSelect) {
+ parseAssembly("declare i32 @any_num()"
+ "define void @test(i1 %Cond) {\n"
+ " %A = call i32 @any_num()\n"
+ " %B = add i32 %A, 1\n"
+ " %C = select i1 %Cond, i32 %A, i32 %B\n"
+ " udiv i32 1, %C"
+ " ret void\n"
+ "}\n");
+ // If A is poison, B is also poison, and therefore C is poison regardless of
+ // the value of %Cond.
+ EXPECT_EQ(programUndefinedIfPoison(A), true);
+}
+
TEST_F(ValueTrackingTest, programUndefinedIfUndefOrPoison) {
parseAssembly("declare i32 @any_num()"
"define void @test(i32 %mask) {\n"