diff --git a/compiler/compiler.go b/compiler/compiler.go
index c42e40c4..2c79047d 100644
--- a/compiler/compiler.go
+++ b/compiler/compiler.go
@@ -23,7 +23,7 @@ import (
 // Version of the compiler pacakge. Must be incremented each time the compiler
 // package changes in a way that affects the generated LLVM module.
 // This version is independent of the TinyGo version number.
-const Version = 23 // last change: fix recursive function types
+const Version = 24 // last change: add layout param to runtime.alloc calls
 
 func init() {
 	llvm.InitializeAllTargets()
@@ -1524,8 +1524,8 @@ func (b *builder) createExpr(expr ssa.Value) (llvm.Value, error) {
 				return llvm.Value{}, b.makeError(expr.Pos(), fmt.Sprintf("value is too big (%v bytes)", size))
 			}
 			sizeValue := llvm.ConstInt(b.uintptrType, size, false)
-			nilPtr := llvm.ConstNull(b.i8ptrType)
-			buf := b.createRuntimeCall("alloc", []llvm.Value{sizeValue, nilPtr}, expr.Comment)
+			layoutValue := b.createObjectLayout(typ, expr.Pos())
+			buf := b.createRuntimeCall("alloc", []llvm.Value{sizeValue, layoutValue}, expr.Comment)
 			buf = b.CreateBitCast(buf, llvm.PointerType(typ, 0), "")
 			return buf, nil
 		} else {
@@ -1737,8 +1737,8 @@ func (b *builder) createExpr(expr ssa.Value) (llvm.Value, error) {
 			return llvm.Value{}, err
 		}
 		sliceSize := b.CreateBinOp(llvm.Mul, elemSizeValue, sliceCapCast, "makeslice.cap")
-		nilPtr := llvm.ConstNull(b.i8ptrType)
-		slicePtr := b.createRuntimeCall("alloc", []llvm.Value{sliceSize, nilPtr}, "makeslice.buf")
+		layoutValue := b.createObjectLayout(llvmElemType, expr.Pos())
+		slicePtr := b.createRuntimeCall("alloc", []llvm.Value{sliceSize, layoutValue}, "makeslice.buf")
 		slicePtr = b.CreateBitCast(slicePtr, llvm.PointerType(llvmElemType, 0), "makeslice.array")
 
 		// Extend or truncate if necessary. This is safe as we've already done
diff --git a/compiler/compiler_test.go b/compiler/compiler_test.go
index c80b822c..f1a0e00c 100644
--- a/compiler/compiler_test.go
+++ b/compiler/compiler_test.go
@@ -54,6 +54,7 @@ func TestCompiler(t *testing.T) {
 		{"channel.go", ""},
 		{"intrinsics.go", "cortex-m-qemu"},
 		{"intrinsics.go", "wasm"},
+		{"gc.go", ""},
 	}
 
 	_, minor, err := goenv.GetGorootVersion(goenv.Get("GOROOT"))
diff --git a/compiler/llvm.go b/compiler/llvm.go
index da4013e6..17f642d7 100644
--- a/compiler/llvm.go
+++ b/compiler/llvm.go
@@ -1,6 +1,11 @@
 package compiler
 
 import (
+	"fmt"
+	"go/token"
+	"go/types"
+	"math/big"
+
 	"github.com/tinygo-org/tinygo/compiler/llvmutil"
 	"tinygo.org/x/go-llvm"
 )
@@ -52,3 +57,199 @@ func (c *compilerContext) makeGlobalArray(buf []byte, name string, elementType l
 	global.SetInitializer(value)
 	return global
 }
+
+// createObjectLayout returns a LLVM value (of type i8*) that describes where
+// there are pointers in the type t. If all the data fits in a word, it is
+// returned as a word. Otherwise it will store the data in a global.
+//
+// The value contains two pieces of information: the length of the object and
+// which words contain a pointer (indicated by setting the given bit to 1). For
+// arrays, only the element is stored. This works because the GC knows the
+// object size and can therefore know how this value is repeated in the object.
+func (c *compilerContext) createObjectLayout(t llvm.Type, pos token.Pos) llvm.Value {
+	// Use the element type for arrays. This works even for nested arrays.
+	for {
+		kind := t.TypeKind()
+		if kind == llvm.ArrayTypeKind {
+			t = t.ElementType()
+			continue
+		}
+		if kind == llvm.StructTypeKind {
+			fields := t.StructElementTypes()
+			if len(fields) == 1 {
+				t = fields[0]
+				continue
+			}
+		}
+		break
+	}
+
+	// Do a few checks to see whether we need to generate any object layout
+	// information at all.
+	objectSizeBytes := c.targetData.TypeAllocSize(t)
+	pointerSize := c.targetData.TypeAllocSize(c.i8ptrType)
+	pointerAlignment := c.targetData.PrefTypeAlignment(c.i8ptrType)
+	if objectSizeBytes < pointerSize {
+		// Too small to contain a pointer.
+		layout := (uint64(1) << 1) | 1
+		return llvm.ConstIntToPtr(llvm.ConstInt(c.uintptrType, layout, false), c.i8ptrType)
+	}
+	bitmap := c.getPointerBitmap(t, pos)
+	if bitmap.BitLen() == 0 {
+		// There are no pointers in this type, so we can simplify the layout.
+		// TODO: this can be done in many other cases, e.g. when allocating an
+		// array (like [4][]byte, which repeats a slice 4 times).
+		layout := (uint64(1) << 1) | 1
+		return llvm.ConstIntToPtr(llvm.ConstInt(c.uintptrType, layout, false), c.i8ptrType)
+	}
+	if objectSizeBytes%uint64(pointerAlignment) != 0 {
+		// This shouldn't happen except for packed structs, which aren't
+		// currently used.
+		c.addError(pos, "internal error: unexpected object size for object with pointer field")
+		return llvm.ConstNull(c.i8ptrType)
+	}
+	objectSizeWords := objectSizeBytes / uint64(pointerAlignment)
+
+	pointerBits := pointerSize * 8
+	var sizeFieldBits uint64
+	switch pointerBits {
+	case 16:
+		sizeFieldBits = 4
+	case 32:
+		sizeFieldBits = 5
+	case 64:
+		sizeFieldBits = 6
+	default:
+		panic("unknown pointer size")
+	}
+	layoutFieldBits := pointerBits - 1 - sizeFieldBits
+
+	// Try to emit the value as an inline integer. This is possible in most
+	// cases.
+	if objectSizeWords < layoutFieldBits {
+		// If it can be stored directly in the pointer value, do so.
+		// The runtime knows that if the least significant bit of the pointer is
+		// set, the pointer contains the value itself.
+		layout := bitmap.Uint64()<<(sizeFieldBits+1) | (objectSizeWords << 1) | 1
+		return llvm.ConstIntToPtr(llvm.ConstInt(c.uintptrType, layout, false), c.i8ptrType)
+	}
+
+	// Unfortunately, the object layout is too big to fit in a pointer-sized
+	// integer. Store it in a global instead.
+
+	// Try first whether the global already exists. All objects with a
+	// particular name have the same type, so this is possible.
+	globalName := "runtime/gc.layout:" + fmt.Sprintf("%d-%0*x", objectSizeWords, (objectSizeWords+15)/16, bitmap)
+	global := c.mod.NamedGlobal(globalName)
+	if !global.IsNil() {
+		return llvm.ConstBitCast(global, c.i8ptrType)
+	}
+
+	// Create the global initializer.
+	bitmapBytes := make([]byte, int(objectSizeWords+7)/8)
+	copy(bitmapBytes, bitmap.Bytes())
+	var bitmapByteValues []llvm.Value
+	for _, b := range bitmapBytes {
+		bitmapByteValues = append(bitmapByteValues, llvm.ConstInt(c.ctx.Int8Type(), uint64(b), false))
+	}
+	initializer := c.ctx.ConstStruct([]llvm.Value{
+		llvm.ConstInt(c.uintptrType, objectSizeWords, false),
+		llvm.ConstArray(c.ctx.Int8Type(), bitmapByteValues),
+	}, false)
+
+	global = llvm.AddGlobal(c.mod, initializer.Type(), globalName)
+	global.SetInitializer(initializer)
+	global.SetUnnamedAddr(true)
+	global.SetGlobalConstant(true)
+	global.SetLinkage(llvm.LinkOnceODRLinkage)
+	if c.targetData.PrefTypeAlignment(c.uintptrType) < 2 {
+		// AVR doesn't have alignment by default.
+		global.SetAlignment(2)
+	}
+	if c.Debug && pos != token.NoPos {
+		// Creating a fake global so that the value can be inspected in GDB.
+		// For example, the layout for strings.stringFinder (as of Go version
+		// 1.15) has the following type according to GDB:
+		//   type = struct {
+		//       uintptr numBits;
+		//       uint8 data[33];
+		//   }
+		// ...that's sort of a mixed C/Go type, but it is readable. More
+		// importantly, these object layout globals can be read and printed by
+		// GDB which may be useful for debugging.
+		position := c.program.Fset.Position(pos)
+		diglobal := c.dibuilder.CreateGlobalVariableExpression(c.difiles[position.Filename], llvm.DIGlobalVariableExpression{
+			Name: globalName,
+			File: c.getDIFile(position.Filename),
+			Line: position.Line,
+			Type: c.getDIType(types.NewStruct([]*types.Var{
+				types.NewVar(pos, nil, "numBits", types.Typ[types.Uintptr]),
+				types.NewVar(pos, nil, "data", types.NewArray(types.Typ[types.Byte], int64(len(bitmapByteValues)))),
+			}, nil)),
+			LocalToUnit: false,
+			Expr:        c.dibuilder.CreateExpression(nil),
+		})
+		global.AddMetadata(0, diglobal)
+	}
+
+	return llvm.ConstBitCast(global, c.i8ptrType)
+}
+
+// getPointerBitmap scans the given LLVM type for pointers and sets bits in a
+// bigint at the word offset that contains a pointer. This scan is recursive.
+func (c *compilerContext) getPointerBitmap(typ llvm.Type, pos token.Pos) *big.Int {
+	alignment := c.targetData.PrefTypeAlignment(c.i8ptrType)
+	switch typ.TypeKind() {
+	case llvm.IntegerTypeKind, llvm.FloatTypeKind, llvm.DoubleTypeKind:
+		return big.NewInt(0)
+	case llvm.PointerTypeKind:
+		return big.NewInt(1)
+	case llvm.StructTypeKind:
+		ptrs := big.NewInt(0)
+		if typ.StructName() == "runtime.funcValue" {
+			// Hack: the type runtime.funcValue contains an 'id' field which is
+			// of type uintptr, but before the LowerFuncValues pass it actually
+			// contains a pointer (ptrtoint) to a global. This trips up the
+			// interp package. Therefore, make the id field a pointer for now.
+			typ = c.ctx.StructType([]llvm.Type{c.i8ptrType, c.i8ptrType}, false)
+		}
+		for i, subtyp := range typ.StructElementTypes() {
+			subptrs := c.getPointerBitmap(subtyp, pos)
+			if subptrs.BitLen() == 0 {
+				continue
+			}
+			offset := c.targetData.ElementOffset(typ, i)
+			if offset%uint64(alignment) != 0 {
+				// This error will let the compilation fail, but by continuing
+				// the error can still easily be shown.
+				c.addError(pos, "internal error: allocated struct contains unaligned pointer")
+				continue
+			}
+			subptrs.Lsh(subptrs, uint(offset)/uint(alignment))
+			ptrs.Or(ptrs, subptrs)
+		}
+		return ptrs
+	case llvm.ArrayTypeKind:
+		subtyp := typ.ElementType()
+		subptrs := c.getPointerBitmap(subtyp, pos)
+		ptrs := big.NewInt(0)
+		if subptrs.BitLen() == 0 {
+			return ptrs
+		}
+		elementSize := c.targetData.TypeAllocSize(subtyp)
+		if elementSize%uint64(alignment) != 0 {
+			// This error will let the compilation fail (but continues so that
+			// other errors can be shown).
+			c.addError(pos, "internal error: allocated array contains unaligned pointer")
+			return ptrs
+		}
+		for i := 0; i < typ.ArrayLength(); i++ {
+			ptrs.Lsh(ptrs, uint(elementSize)/uint(alignment))
+			ptrs.Or(ptrs, subptrs)
+		}
+		return ptrs
+	default:
+		// Should not happen.
+		panic("unknown LLVM type")
+	}
+}
diff --git a/compiler/testdata/gc.go b/compiler/testdata/gc.go
new file mode 100644
index 00000000..74e0358a
--- /dev/null
+++ b/compiler/testdata/gc.go
@@ -0,0 +1,72 @@
+package main
+
+var (
+	scalar1 *byte
+	scalar2 *int32
+	scalar3 *int64
+	scalar4 *float32
+
+	array1 *[3]byte
+	array2 *[71]byte
+	array3 *[3]*byte
+
+	struct1 *struct{}
+	struct2 *struct {
+		x int
+		y int
+	}
+	struct3 *struct {
+		x *byte
+		y [60]uintptr
+		z *byte
+	}
+
+	slice1 []byte
+	slice2 []*int
+	slice3 [][]byte
+)
+
+func newScalar() {
+	scalar1 = new(byte)
+	scalar2 = new(int32)
+	scalar3 = new(int64)
+	scalar4 = new(float32)
+}
+
+func newArray() {
+	array1 = new([3]byte)
+	array2 = new([71]byte)
+	array3 = new([3]*byte)
+}
+
+func newStruct() {
+	struct1 = new(struct{})
+	struct2 = new(struct {
+		x int
+		y int
+	})
+	struct3 = new(struct {
+		x *byte
+		y [60]uintptr
+		z *byte
+	})
+}
+
+func newFuncValue() *func() {
+	// On some platforms that use runtime.funcValue ("switch" style) function
+	// values, a func value is allocated as having two pointer words while the
+	// struct looks like {unsafe.Pointer; uintptr}. This is so that the interp
+	// package won't get confused, see getPointerBitmap in compiler/llvm.go for
+	// details.
+	return new(func())
+}
+
+func makeSlice() {
+	slice1 = make([]byte, 5)
+	slice2 = make([]*int, 5)
+	slice3 = make([][]byte, 5)
+}
+
+func makeInterface(v complex128) interface{} {
+	return v // always stored in an allocation
+}
diff --git a/compiler/testdata/gc.ll b/compiler/testdata/gc.ll
new file mode 100644
index 00000000..7ac0aa1b
--- /dev/null
+++ b/compiler/testdata/gc.ll
@@ -0,0 +1,113 @@
+; ModuleID = 'gc.go'
+source_filename = "gc.go"
+target datalayout = "e-m:e-p:32:32-i64:64-n32:64-S128"
+target triple = "wasm32-unknown-wasi"
+
+%runtime.typecodeID = type { %runtime.typecodeID*, i32, %runtime.interfaceMethodInfo*, %runtime.typecodeID*, i32 }
+%runtime.interfaceMethodInfo = type { i8*, i32 }
+%runtime.funcValue = type { i8*, i32 }
+%runtime._interface = type { i32, i8* }
+
+@main.scalar1 = hidden global i8* null, align 4
+@main.scalar2 = hidden global i32* null, align 4
+@main.scalar3 = hidden global i64* null, align 4
+@main.scalar4 = hidden global float* null, align 4
+@main.array1 = hidden global [3 x i8]* null, align 4
+@main.array2 = hidden global [71 x i8]* null, align 4
+@main.array3 = hidden global [3 x i8*]* null, align 4
+@main.struct1 = hidden global {}* null, align 4
+@main.struct2 = hidden global { i32, i32 }* null, align 4
+@main.struct3 = hidden global { i8*, [60 x i32], i8* }* null, align 4
+@main.slice1 = hidden global { i8*, i32, i32 } zeroinitializer, align 8
+@main.slice2 = hidden global { i32**, i32, i32 } zeroinitializer, align 8
+@main.slice3 = hidden global { { i8*, i32, i32 }*, i32, i32 } zeroinitializer, align 8
+@"runtime/gc.layout:62-2000000000000001" = linkonce_odr unnamed_addr constant { i32, [8 x i8] } { i32 62, [8 x i8] c" \00\00\00\00\00\00\01" }
+@"reflect/types.type:basic:complex128" = linkonce_odr constant %runtime.typecodeID { %runtime.typecodeID* null, i32 0, %runtime.interfaceMethodInfo* null, %runtime.typecodeID* @"reflect/types.type:pointer:basic:complex128", i32 0 }
+@"reflect/types.type:pointer:basic:complex128" = linkonce_odr constant %runtime.typecodeID { %runtime.typecodeID* @"reflect/types.type:basic:complex128", i32 0, %runtime.interfaceMethodInfo* null, %runtime.typecodeID* null, i32 0 }
+
+declare noalias nonnull i8* @runtime.alloc(i32, i8*, i8*, i8*)
+
+; Function Attrs: nounwind
+define hidden void @main.init(i8* %context, i8* %parentHandle) unnamed_addr #0 {
+entry:
+  ret void
+}
+
+; Function Attrs: nounwind
+define hidden void @main.newScalar(i8* %context, i8* %parentHandle) unnamed_addr #0 {
+entry:
+  %new = call i8* @runtime.alloc(i32 1, i8* nonnull inttoptr (i32 3 to i8*), i8* undef, i8* null) #0
+  store i8* %new, i8** @main.scalar1, align 4
+  %new1 = call i8* @runtime.alloc(i32 4, i8* nonnull inttoptr (i32 3 to i8*), i8* undef, i8* null) #0
+  store i8* %new1, i8** bitcast (i32** @main.scalar2 to i8**), align 4
+  %new2 = call i8* @runtime.alloc(i32 8, i8* nonnull inttoptr (i32 3 to i8*), i8* undef, i8* null) #0
+  store i8* %new2, i8** bitcast (i64** @main.scalar3 to i8**), align 4
+  %new3 = call i8* @runtime.alloc(i32 4, i8* nonnull inttoptr (i32 3 to i8*), i8* undef, i8* null) #0
+  store i8* %new3, i8** bitcast (float** @main.scalar4 to i8**), align 4
+  ret void
+}
+
+; Function Attrs: nounwind
+define hidden void @main.newArray(i8* %context, i8* %parentHandle) unnamed_addr #0 {
+entry:
+  %new = call i8* @runtime.alloc(i32 3, i8* nonnull inttoptr (i32 3 to i8*), i8* undef, i8* null) #0
+  store i8* %new, i8** bitcast ([3 x i8]** @main.array1 to i8**), align 4
+  %new1 = call i8* @runtime.alloc(i32 71, i8* nonnull inttoptr (i32 3 to i8*), i8* undef, i8* null) #0
+  store i8* %new1, i8** bitcast ([71 x i8]** @main.array2 to i8**), align 4
+  %new2 = call i8* @runtime.alloc(i32 12, i8* nonnull inttoptr (i32 67 to i8*), i8* undef, i8* null) #0
+  store i8* %new2, i8** bitcast ([3 x i8*]** @main.array3 to i8**), align 4
+  ret void
+}
+
+; Function Attrs: nounwind
+define hidden void @main.newStruct(i8* %context, i8* %parentHandle) unnamed_addr #0 {
+entry:
+  %new = call i8* @runtime.alloc(i32 0, i8* nonnull inttoptr (i32 3 to i8*), i8* undef, i8* null) #0
+  store i8* %new, i8** bitcast ({}** @main.struct1 to i8**), align 4
+  %new1 = call i8* @runtime.alloc(i32 8, i8* nonnull inttoptr (i32 3 to i8*), i8* undef, i8* null) #0
+  store i8* %new1, i8** bitcast ({ i32, i32 }** @main.struct2 to i8**), align 4
+  %new2 = call i8* @runtime.alloc(i32 248, i8* bitcast ({ i32, [8 x i8] }* @"runtime/gc.layout:62-2000000000000001" to i8*), i8* undef, i8* null) #0
+  store i8* %new2, i8** bitcast ({ i8*, [60 x i32], i8* }** @main.struct3 to i8**), align 4
+  ret void
+}
+
+; Function Attrs: nounwind
+define hidden %runtime.funcValue* @main.newFuncValue(i8* %context, i8* %parentHandle) unnamed_addr #0 {
+entry:
+  %new = call i8* @runtime.alloc(i32 8, i8* nonnull inttoptr (i32 197 to i8*), i8* undef, i8* null) #0
+  %0 = bitcast i8* %new to %runtime.funcValue*
+  ret %runtime.funcValue* %0
+}
+
+; Function Attrs: nounwind
+define hidden void @main.makeSlice(i8* %context, i8* %parentHandle) unnamed_addr #0 {
+entry:
+  %makeslice = call i8* @runtime.alloc(i32 5, i8* nonnull inttoptr (i32 3 to i8*), i8* undef, i8* null) #0
+  store i8* %makeslice, i8** getelementptr inbounds ({ i8*, i32, i32 }, { i8*, i32, i32 }* @main.slice1, i32 0, i32 0), align 8
+  store i32 5, i32* getelementptr inbounds ({ i8*, i32, i32 }, { i8*, i32, i32 }* @main.slice1, i32 0, i32 1), align 4
+  store i32 5, i32* getelementptr inbounds ({ i8*, i32, i32 }, { i8*, i32, i32 }* @main.slice1, i32 0, i32 2), align 8
+  %makeslice1 = call i8* @runtime.alloc(i32 20, i8* nonnull inttoptr (i32 67 to i8*), i8* undef, i8* null) #0
+  store i8* %makeslice1, i8** bitcast ({ i32**, i32, i32 }* @main.slice2 to i8**), align 8
+  store i32 5, i32* getelementptr inbounds ({ i32**, i32, i32 }, { i32**, i32, i32 }* @main.slice2, i32 0, i32 1), align 4
+  store i32 5, i32* getelementptr inbounds ({ i32**, i32, i32 }, { i32**, i32, i32 }* @main.slice2, i32 0, i32 2), align 8
+  %makeslice3 = call i8* @runtime.alloc(i32 60, i8* nonnull inttoptr (i32 71 to i8*), i8* undef, i8* null) #0
+  store i8* %makeslice3, i8** bitcast ({ { i8*, i32, i32 }*, i32, i32 }* @main.slice3 to i8**), align 8
+  store i32 5, i32* getelementptr inbounds ({ { i8*, i32, i32 }*, i32, i32 }, { { i8*, i32, i32 }*, i32, i32 }* @main.slice3, i32 0, i32 1), align 4
+  store i32 5, i32* getelementptr inbounds ({ { i8*, i32, i32 }*, i32, i32 }, { { i8*, i32, i32 }*, i32, i32 }* @main.slice3, i32 0, i32 2), align 8
+  ret void
+}
+
+; Function Attrs: nounwind
+define hidden %runtime._interface @main.makeInterface(double %v.r, double %v.i, i8* %context, i8* %parentHandle) unnamed_addr #0 {
+entry:
+  %0 = call i8* @runtime.alloc(i32 16, i8* null, i8* undef, i8* null) #0
+  %.repack = bitcast i8* %0 to double*
+  store double %v.r, double* %.repack, align 8
+  %.repack1 = getelementptr inbounds i8, i8* %0, i32 8
+  %1 = bitcast i8* %.repack1 to double*
+  store double %v.i, double* %1, align 8
+  %2 = insertvalue %runtime._interface { i32 ptrtoint (%runtime.typecodeID* @"reflect/types.type:basic:complex128" to i32), i8* undef }, i8* %0, 1
+  ret %runtime._interface %2
+}
+
+attributes #0 = { nounwind }
diff --git a/compiler/testdata/go1.17.ll b/compiler/testdata/go1.17.ll
index 3e131236..5c26166a 100644
--- a/compiler/testdata/go1.17.ll
+++ b/compiler/testdata/go1.17.ll
@@ -46,7 +46,7 @@ declare void @runtime.sliceToArrayPointerPanic(i8*, i8*)
 ; Function Attrs: nounwind
 define hidden [4 x i32]* @main.SliceToArrayConst(i8* %context, i8* %parentHandle) unnamed_addr #0 {
 entry:
-  %makeslice = call i8* @runtime.alloc(i32 24, i8* null, i8* undef, i8* null) #0
+  %makeslice = call i8* @runtime.alloc(i32 24, i8* nonnull inttoptr (i32 3 to i8*), i8* undef, i8* null) #0
   br i1 false, label %slicetoarray.throw, label %slicetoarray.next
 
 slicetoarray.throw:                               ; preds = %entry
diff --git a/compiler/testdata/goroutine-cortex-m-qemu.ll b/compiler/testdata/goroutine-cortex-m-qemu.ll
index efc51861..079d47f6 100644
--- a/compiler/testdata/goroutine-cortex-m-qemu.ll
+++ b/compiler/testdata/goroutine-cortex-m-qemu.ll
@@ -66,7 +66,7 @@ entry:
 ; Function Attrs: nounwind
 define hidden void @main.closureFunctionGoroutine(i8* %context, i8* %parentHandle) unnamed_addr #0 {
 entry:
-  %n = call i8* @runtime.alloc(i32 4, i8* null, i8* undef, i8* null) #0
+  %n = call i8* @runtime.alloc(i32 4, i8* nonnull inttoptr (i32 3 to i8*), i8* undef, i8* null) #0
   %0 = bitcast i8* %n to i32*
   store i32 3, i32* %0, align 4
   %1 = call i8* @runtime.alloc(i32 8, i8* null, i8* undef, i8* null) #0
diff --git a/compiler/testdata/goroutine-wasm.ll b/compiler/testdata/goroutine-wasm.ll
index 4a346c11..553eb1cc 100644
--- a/compiler/testdata/goroutine-wasm.ll
+++ b/compiler/testdata/goroutine-wasm.ll
@@ -51,7 +51,7 @@ entry:
 ; Function Attrs: nounwind
 define hidden void @main.closureFunctionGoroutine(i8* %context, i8* %parentHandle) unnamed_addr #0 {
 entry:
-  %n = call i8* @runtime.alloc(i32 4, i8* null, i8* undef, i8* null) #0
+  %n = call i8* @runtime.alloc(i32 4, i8* nonnull inttoptr (i32 3 to i8*), i8* undef, i8* null) #0
   %0 = bitcast i8* %n to i32*
   store i32 3, i32* %0, align 4
   %1 = call i8* @runtime.alloc(i32 8, i8* null, i8* undef, i8* null) #0
diff --git a/compiler/testdata/slice.ll b/compiler/testdata/slice.ll
index da257c4c..847d29fb 100644
--- a/compiler/testdata/slice.ll
+++ b/compiler/testdata/slice.ll
@@ -44,7 +44,7 @@ declare void @runtime.lookupPanic(i8*, i8*)
 ; Function Attrs: nounwind
 define hidden { i32*, i32, i32 } @main.sliceAppendValues(i32* %ints.data, i32 %ints.len, i32 %ints.cap, i8* %context, i8* %parentHandle) unnamed_addr #0 {
 entry:
-  %varargs = call i8* @runtime.alloc(i32 12, i8* null, i8* undef, i8* null) #0
+  %varargs = call i8* @runtime.alloc(i32 12, i8* nonnull inttoptr (i32 3 to i8*), i8* undef, i8* null) #0
   %0 = bitcast i8* %varargs to i32*
   store i32 1, i32* %0, align 4
   %1 = getelementptr inbounds i8, i8* %varargs, i32 4
@@ -105,7 +105,7 @@ slice.throw:                                      ; preds = %entry
   unreachable
 
 slice.next:                                       ; preds = %entry
-  %makeslice.buf = call i8* @runtime.alloc(i32 %len, i8* null, i8* undef, i8* null) #0
+  %makeslice.buf = call i8* @runtime.alloc(i32 %len, i8* nonnull inttoptr (i32 3 to i8*), i8* undef, i8* null) #0
   %0 = insertvalue { i8*, i32, i32 } undef, i8* %makeslice.buf, 0
   %1 = insertvalue { i8*, i32, i32 } %0, i32 %len, 1
   %2 = insertvalue { i8*, i32, i32 } %1, i32 %len, 2
@@ -126,7 +126,7 @@ slice.throw:                                      ; preds = %entry
 
 slice.next:                                       ; preds = %entry
   %makeslice.cap = shl i32 %len, 1
-  %makeslice.buf = call i8* @runtime.alloc(i32 %makeslice.cap, i8* null, i8* undef, i8* null) #0
+  %makeslice.buf = call i8* @runtime.alloc(i32 %makeslice.cap, i8* nonnull inttoptr (i32 3 to i8*), i8* undef, i8* null) #0
   %makeslice.array = bitcast i8* %makeslice.buf to i16*
   %0 = insertvalue { i16*, i32, i32 } undef, i16* %makeslice.array, 0
   %1 = insertvalue { i16*, i32, i32 } %0, i32 %len, 1
@@ -146,7 +146,7 @@ slice.throw:                                      ; preds = %entry
 
 slice.next:                                       ; preds = %entry
   %makeslice.cap = mul i32 %len, 3
-  %makeslice.buf = call i8* @runtime.alloc(i32 %makeslice.cap, i8* null, i8* undef, i8* null) #0
+  %makeslice.buf = call i8* @runtime.alloc(i32 %makeslice.cap, i8* nonnull inttoptr (i32 3 to i8*), i8* undef, i8* null) #0
   %makeslice.array = bitcast i8* %makeslice.buf to [3 x i8]*
   %0 = insertvalue { [3 x i8]*, i32, i32 } undef, [3 x i8]* %makeslice.array, 0
   %1 = insertvalue { [3 x i8]*, i32, i32 } %0, i32 %len, 1
@@ -166,7 +166,7 @@ slice.throw:                                      ; preds = %entry
 
 slice.next:                                       ; preds = %entry
   %makeslice.cap = shl i32 %len, 2
-  %makeslice.buf = call i8* @runtime.alloc(i32 %makeslice.cap, i8* null, i8* undef, i8* null) #0
+  %makeslice.buf = call i8* @runtime.alloc(i32 %makeslice.cap, i8* nonnull inttoptr (i32 3 to i8*), i8* undef, i8* null) #0
   %makeslice.array = bitcast i8* %makeslice.buf to i32*
   %0 = insertvalue { i32*, i32, i32 } undef, i32* %makeslice.array, 0
   %1 = insertvalue { i32*, i32, i32 } %0, i32 %len, 1