go/src/cmd/compile/internal/ssa/branchelim.go

// branchelim tries to eliminate branches by
// generating CondSelect instructions.
//
// Search for basic blocks that look like
//
//	bb0            bb0
//	 | \          /   \
//	 | bb1  or  bb1   bb2    <- trivial if/else blocks
//	 | /          \   /
//	bb2            bb3
//
// where the intermediate blocks are mostly empty (with no side-effects);
// rewrite Phis in the postdominator as CondSelects.
func branchelim(f *Func) { … }

func canCondSelect(v *Value, arch string, loadAddr *sparseSet) bool { … }

// elimIf converts the one-way branch starting at dom in f to a conditional move if possible.
// loadAddr is a set of values which are used to compute the address of a load.
// Those values are exempt from CMOV generation.
func elimIf(f *Func, loadAddr *sparseSet, dom *Block) bool { … }

// is this a BlockPlain with one predecessor?
func isLeafPlain(b *Block) bool { … }

func clobberBlock(b *Block) { … }

// elimIfElse converts the two-way branch starting at dom in f to a conditional move if possible.
// loadAddr is a set of values which are used to compute the address of a load.
// Those values are exempt from CMOV generation.
func elimIfElse(f *Func, loadAddr *sparseSet, b *Block) bool { … }

// shouldElimIfElse reports whether estimated cost of eliminating branch
// is lower than threshold.
func shouldElimIfElse(no, yes, post *Block, arch string) bool { … }

// canSpeculativelyExecute reports whether every value in the block can
// be evaluated without causing any observable side effects (memory
// accesses, panics and so on) except for execution time changes. It
// also ensures that the block does not contain any phis which we can't
// speculatively execute.
// Warning: this function cannot currently detect values that represent
// instructions the execution of which need to be guarded with CPU
// hardware feature checks. See issue #34950.
func canSpeculativelyExecute(b *Block) bool { … }

func isDivMod(op Op) bool { … }

func isPtrArithmetic(op Op) bool { … }