GATE CS Compiler Design questions

Which one of the following grammars is free from left recursion?

The least number of temporary variables required to create a three-address code in static single assignment form for the expression $q + r / 3 + s - t * 5 + u * v/w$ is__________________.

A variable $x$ is said to be live at a statement $s_{i}$ in a program if the following three conditions hold simultaneously: There exists a statement $S_{j}$ that uses $x$ There is a path from $S_{i}$ to $S_{j}$ in the flow graph corresponding to the program The path has no intervening assignment to $x$ including at $S_{i}$ and $S_{j}$ The …

Which one of the following is TRUE at any valid state in shift-reduce parsing?

For computer based on three-address instruction formats, each address field can be used to specify which of the following: (S1) A memory operand (S2) A processor register (S3) An implied accumulator register

Consider the intermediate code given below. (1) i=1 (2) j=1 (3) t1 = 5 * i (4) t2 = t1 + j (5) t3 = 4 * t2 (6) t4 = t3 (7) a[t4] = -1 (8) j = j + 1 (9) if j <= 5 goto (3) (10) i = i +1 (11) if i < 5 goto (2) The number of nodes and edges in control-flow-graph constructed for the above code, respectively, are

Match the following: …

In the context of abstract-syntax-tree (AST) and control-flow-graph (CFG), which one of the following is TRUE?

Consider the following grammar G $S \rightarrow F \mid H$ $F \rightarrow p \mid c$ $H \rightarrow d \mid c$ Where $S$, $F$, and $H$ are non-terminal symbols, $p, d$, and $c$ are terminal symbols. Which of the following statement(s) is/are correct? S1: LL(1) can parse all strings that are generated using grammar G S2: LR(1) can parse all …

Among simple LR (SLR), canonical LR, and look-ahead LR (LALR), which of the following pairs identify the method that is very easy to implement and the method that is the most powerful, in that order?

A canonical set of items is given below $S \to L .> R$ $Q \to R.$ On input symbol $<$ the set has

Which one of the following is FALSE?

Consider the expression tree shown. Each leaf represents a numerical value, which can either be $0$ or $1$. Over all possible choices of the values at the leaves, the maximum possible value of the expression represented by the tree is ___.

For a C program accessing $\mathbf{X[i] [j] [k]}$, the following intermediate code is generated by a compiler. Assume that the size of an integer is $32$ bits and the size of a character is $8$ bits. t0 = i ∗ 1024 t1 = j ∗ 32 t2 = k ∗ 4 t3 = t1 + t0 t4 = t3 + t2 t5 = X[t4] Which one of the following statements about the source code for the C program is …

Which one of the following is NOT performed during compilation?

Consider the grammar defined by the following production rules, with two operators $∗$ and $+$ $S\:\to\:T∗P$ $T\:\to\:U\mid T∗U$ $P\:\to\:Q+P\mid Q$ $Q\:\to Id$ $U\:\to Id$ Which one of the following is TRUE?

Consider the basic block given below. a = b + c c = a + d d = b + c e = d - b a = e + b The minimum number of nodes and edges present in the DAG representation of the above basic block respectively are

One of the purposes of using intermediate code in compilers is to

Which of the following statements are CORRECT? Static allocation of all data areas by a compiler makes it impossible to implement recursion. Automatic garbage collection is essential to implement recursion. Dynamic allocation of activation records is essential to implement recursion. Both heap and stack are essential to implement recursion.

The minimum number of arithmetic operations required to evaluate the polynomial $P(X) = X^5+4X^3+6X+5$ for a given value of $X$, using only one temporary variable is ______.