We should be check whether lb + step >= ub to determine
whether this is a single iteration. Previously we were
checking lb + lb >= ub.
Differential Revision: https://reviews.llvm.org/D95440
An SCF 'for' loop does not iterate if its lower bound is equal to its upper
bound. Remove loops where both bounds are the same SSA value as such bounds are
guaranteed to be equal. Similarly, remove 'parallel' loops where at least one
pair of respective lower/upper bounds is specified by the same SSA value.
Reviewed By: gysit
Differential Revision: https://reviews.llvm.org/D91880
Add canoncalization patterns to remove zero-iteration 'for' loops, replace
single-iteration 'for' loops with their bodies; remove known-false conditionals
with no 'else' branch and replace conditionals with known value by the
respective region. Although similar transformations are performed at the CFG
level, not all flows reach that level, e.g., the GPU flow may want to remove
single-iteration loops before deciding on loop mapping to thread dimensions.
Reviewed By: herhut
Differential Revision: https://reviews.llvm.org/D91865
The patch adds a canonicalization pattern that removes the unused results of scf.if operation. As a result, cse may remove unused computations in the then and else regions of the scf.if operation.
Reviewed By: mehdi_amini
Differential Revision: https://reviews.llvm.org/D89029