What is SSA form?

SSA form in the explanations

• In SSA form, variables are renamed so each is assigned only once, and φ functions select values at join points.

  Which is a characteristic of an IR in SSA form?

• In SSA form the then-branch assignment becomes x1 and the else-branch assignment x2, so after the join the computation of y must specify which x to use.

  Converting the code above to SSA form inserts an expression…

Questions that mention SSA form (2)

1. Which is a characteristic of an IR in SSA form?
2. Converting the code above to SSA form inserts an expression like "x3 = φ(x1, x2)" after the if statement. What does the φ function do?

Related terms

Abstract syntax tree Basic block Common subexpression elimination Constant folding Control-flow graph Function inlining Instruction scheduling Intermediate representation JIT compilation Lexical analysis