diff options
| -rw-r--r-- | src/cmd/compile/internal/ssa/prove.go | 17 |
1 files changed, 12 insertions, 5 deletions
diff --git a/src/cmd/compile/internal/ssa/prove.go b/src/cmd/compile/internal/ssa/prove.go index 5617edb21f..93bd525c38 100644 --- a/src/cmd/compile/internal/ssa/prove.go +++ b/src/cmd/compile/internal/ssa/prove.go @@ -1917,15 +1917,22 @@ func (ft *factsTable) flowLimit(v *Value) bool { // See if we can get any facts because v is the result of signed mod by a constant. // The mod operation has already been rewritten, so we have to try and reconstruct it. -// x % d +// +// x % d +// // is rewritten as -// x - (x / d) * d +// +// x - (x / d) * d +// // furthermore, the divide itself gets rewritten. If d is a power of 2 (d == 1<<k), we do -// (x / d) * d = ((x + adj) >> k) << k -// = (x + adj) & (-1<<k) +// +// (x / d) * d = ((x + adj) >> k) << k +// = (x + adj) & (-1<<k) +// // with adj being an adjustment in case x is negative (see below). // if d is not a power of 2, we do -// x / d = ... TODO ... +// +// x / d = ... TODO ... func (ft *factsTable) detectSignedMod(v *Value) bool { if ft.detectSignedModByPowerOfTwo(v) { return true |