2 files changed, 0 insertions, 132 deletions

diff --git a/src/cmd/compile/internal/ssa/compile.go b/src/cmd/compile/internal/ssa/compile.go
index 2edf1ba463..bd90235682 100644
--- a/src/cmd/compile/internal/ssa/compile.go
+++ b/src/cmd/compile/internal/ssa/compile.go
@@ -342,7 +342,6 @@ var passes = [...]pass{
 	{name: "phiopt", fn: phiopt},
 	{name: "nilcheckelim", fn: nilcheckelim},
 	{name: "prove", fn: prove},
-	{name: "loopbce", fn: loopbce},
 	{name: "decompose builtin", fn: decomposeBuiltIn, required: true},
 	{name: "softfloat", fn: softfloat, required: true},
 	{name: "late opt", fn: opt, required: true}, // TODO: split required rules and optimizing rules
diff --git a/src/cmd/compile/internal/ssa/loopbce.go b/src/cmd/compile/internal/ssa/loopbce.go
index 7f2da4870e..0ad274fc07 100644
--- a/src/cmd/compile/internal/ssa/loopbce.go
+++ b/src/cmd/compile/internal/ssa/loopbce.go
@@ -159,127 +159,6 @@ nextb:
 	return iv
 }
 
-// loopbce performs loop based bounds check elimination.
-func loopbce(f *Func) {
-	ivList := findIndVar(f)
-
-	m := make(map[*Value]indVar)
-	for _, iv := range ivList {
-		m[iv.ind] = iv
-	}
-
-	removeBoundsChecks(f, m)
-}
-
-// removesBoundsChecks remove IsInBounds and IsSliceInBounds based on the induction variables.
-func removeBoundsChecks(f *Func, m map[*Value]indVar) {
-	sdom := f.sdom()
-	for _, b := range f.Blocks {
-		if b.Kind != BlockIf {
-			continue
-		}
-
-		v := b.Control
-
-		// Simplify:
-		// (IsInBounds ind max) where 0 <= const == min <= ind < max.
-		// (IsSliceInBounds ind max) where 0 <= const == min <= ind < max.
-		// Found in:
-		//	for i := range a {
-		//		use a[i]
-		//		use a[i:]
-		//		use a[:i]
-		//	}
-		if v.Op == OpIsInBounds || v.Op == OpIsSliceInBounds {
-			ind, add := dropAdd64(v.Args[0])
-			if ind.Op != OpPhi {
-				goto skip1
-			}
-			if v.Op == OpIsInBounds && add != 0 {
-				goto skip1
-			}
-			if v.Op == OpIsSliceInBounds && (0 > add || add > 1) {
-				goto skip1
-			}
-
-			if iv, has := m[ind]; has && sdom.isAncestorEq(iv.entry, b) && isNonNegative(iv.min) {
-				if v.Args[1] == iv.max {
-					if f.pass.debug > 0 {
-						f.Warnl(b.Pos, "Found redundant %s", v.Op)
-					}
-					goto simplify
-				}
-			}
-		}
-	skip1:
-
-		// Simplify:
-		// (IsSliceInBounds ind (SliceCap a)) where 0 <= min <= ind < max == (SliceLen a)
-		// Found in:
-		//	for i := range a {
-		//		use a[:i]
-		//		use a[:i+1]
-		//	}
-		if v.Op == OpIsSliceInBounds {
-			ind, add := dropAdd64(v.Args[0])
-			if ind.Op != OpPhi {
-				goto skip2
-			}
-			if 0 > add || add > 1 {
-				goto skip2
-			}
-
-			if iv, has := m[ind]; has && sdom.isAncestorEq(iv.entry, b) && isNonNegative(iv.min) {
-				if v.Args[1].Op == OpSliceCap && iv.max.Op == OpSliceLen && v.Args[1].Args[0] == iv.max.Args[0] {
-					if f.pass.debug > 0 {
-						f.Warnl(b.Pos, "Found redundant %s (len promoted to cap)", v.Op)
-					}
-					goto simplify
-				}
-			}
-		}
-	skip2:
-
-		// Simplify
-		// (IsInBounds (Add64 ind) (Const64 [c])) where 0 <= min <= ind < max <= (Const64 [c])
-		// (IsSliceInBounds ind (Const64 [c])) where 0 <= min <= ind < max <= (Const64 [c])
-		if v.Op == OpIsInBounds || v.Op == OpIsSliceInBounds {
-			ind, add := dropAdd64(v.Args[0])
-			if ind.Op != OpPhi {
-				goto skip3
-			}
-
-			// ind + add >= 0 <-> min + add >= 0 <-> min >= -add
-			if iv, has := m[ind]; has && sdom.isAncestorEq(iv.entry, b) && isGreaterOrEqualThan(iv.min, -add) {
-				if !v.Args[1].isGenericIntConst() || !iv.max.isGenericIntConst() {
-					goto skip3
-				}
-
-				limit := v.Args[1].AuxInt
-				if v.Op == OpIsSliceInBounds {
-					// If limit++ overflows signed integer then 0 <= max && max <= limit will be false.
-					limit++
-				}
-
-				if max := iv.max.AuxInt + add; 0 <= max && max <= limit { // handle overflow
-					if f.pass.debug > 0 {
-						f.Warnl(b.Pos, "Found redundant (%s ind %d), ind < %d", v.Op, v.Args[1].AuxInt, iv.max.AuxInt+add)
-					}
-					goto simplify
-				}
-			}
-		}
-	skip3:
-
-		continue
-
-	simplify:
-		f.Logf("removing bounds check %v at %v in %s\n", b.Control, b, f.Name)
-		b.Kind = BlockFirst
-		b.SetControl(nil)
-	}
-}
-
 func dropAdd64(v *Value) (*Value, int64) {
 	if v.Op == OpAdd64 && v.Args[0].Op == OpConst64 {
 		return v.Args[1], v.Args[0].AuxInt
@@ -289,13 +168,3 @@ func dropAdd64(v *Value) (*Value, int64) {
 	}
 	return v, 0
 }
-
-func isGreaterOrEqualThan(v *Value, c int64) bool {
-	if c == 0 {
-		return isNonNegative(v)
-	}
-	if v.isGenericIntConst() && v.AuxInt >= c {
-		return true
-	}
-	return false
-}