diff options
Diffstat (limited to 'gcc/lambda.h')
| -rw-r--r-- | gcc/lambda.h | 42 |
1 files changed, 37 insertions, 5 deletions
diff --git a/gcc/lambda.h b/gcc/lambda.h index b736024..98fe6bd 100644 --- a/gcc/lambda.h +++ b/gcc/lambda.h @@ -29,11 +29,14 @@ Software Foundation, 59 Temple Place - Suite 330, Boston, MA and scalar multiplication. In this vector space, an element is a list of integers. */ typedef int *lambda_vector; + /* An integer matrix. A matrix consists of m vectors of length n (IE all vectors are the same length). */ typedef lambda_vector *lambda_matrix; -/* A transformation matrix. */ +/* A transformation matrix, which is a self-contained ROWSIZE x COLSIZE + matrix. Rather than use floats, we simply keep a single DENOMINATOR that + represents the denominator for every element in the matrix. */ typedef struct { lambda_matrix matrix; @@ -46,7 +49,15 @@ typedef struct #define LTM_COLSIZE(T) ((T)->colsize) #define LTM_DENOMINATOR(T) ((T)->denominator) -/* A vector representing a statement in the body of a loop. */ +/* A vector representing a statement in the body of a loop. + The COEFFICIENTS vector contains a coefficient for each induction variable + in the loop nest containing the statement. + The DENOMINATOR represents the denominator for each coefficient in the + COEFFICIENT vector. + + This structure is used during code generation in order to rewrite the old + induction variable uses in a statement in terms of the newly created + induction variables. */ typedef struct { lambda_vector coefficients; @@ -57,7 +68,18 @@ typedef struct #define LBV_SIZE(T) ((T)->size) #define LBV_DENOMINATOR(T) ((T)->denominator) -/* Piecewise linear expression. */ +/* Piecewise linear expression. + This structure represents a linear expression with terms for the invariants + and induction variables of a loop. + COEFFICIENTS is a vector of coefficients for the induction variables, one + per loop in the loop nest. + CONSTANT is the constant portion of the linear expression + INVARIANT_COEFFICIENTS is a vector of coefficients for the loop invariants, + one per invariant. + DENOMINATOR is the denominator for all of the coefficients and constants in + the expression. + The linear expressions can be linked together using the NEXT field, in + order to represent MAX or MIN of a group of linear expressions. */ typedef struct lambda_linear_expression_s { lambda_vector coefficients; @@ -77,7 +99,12 @@ lambda_linear_expression lambda_linear_expression_new (int, int); void print_lambda_linear_expression (FILE *, lambda_linear_expression, int, int, char); -/* Loop structure. */ +/* Loop structure. Our loop structure consists of a constant representing the + STEP of the loop, a set of linear expressions representing the LOWER_BOUND + of the loop, a set of linear expressions representing the UPPER_BOUND of + the loop, and a set of linear expressions representing the LINEAR_OFFSET of + the loop. The linear offset is a set of linear expressions that are + applied to *both* the lower bound, and the upper bound. */ typedef struct lambda_loop_s { lambda_linear_expression lower_bound; @@ -91,7 +118,12 @@ typedef struct lambda_loop_s #define LL_LINEAR_OFFSET(T) ((T)->linear_offset) #define LL_STEP(T) ((T)->step) -/* Loop nest structure. */ +/* Loop nest structure. + The loop nest structure consists of a set of loop structures (defined + above) in LOOPS, along with an integer representing the DEPTH of the loop, + and an integer representing the number of INVARIANTS in the loop. Both of + these integers are used to size the associated coefficient vectors in the + linear expression structures. */ typedef struct { lambda_loop *loops; |