diff --git a/src/alloy/frontend/ppc/ppc_emit_altivec.cc b/src/alloy/frontend/ppc/ppc_emit_altivec.cc
index dd159ad3d..018f518b7 100644
--- a/src/alloy/frontend/ppc/ppc_emit_altivec.cc
+++ b/src/alloy/frontend/ppc/ppc_emit_altivec.cc
@@ -186,18 +186,29 @@ XEEMITTER(lvxl128,        VX128_1(4, 707),  VX128_1)(PPCFunctionBuilder& f, Inst
 }
 
 XEEMITTER(stvebx,         0x7C00010E, X   )(PPCFunctionBuilder& f, InstrData& i) {
-  XEINSTRNOTIMPLEMENTED();
-  return 1;
+  Value* ea = i.X.RA ? f.Add(f.LoadGPR(i.X.RA), f.LoadGPR(i.X.RB)) : f.LoadGPR(i.X.RB);
+  Value* el = f.And(ea, f.LoadConstant(0xFull));
+  Value* v = f.Extract(f.LoadVR(i.X.RT), el, INT8_TYPE);
+  f.Store(ea, v);
+  return 0;
 }
 
 XEEMITTER(stvehx,         0x7C00014E, X   )(PPCFunctionBuilder& f, InstrData& i) {
-  XEINSTRNOTIMPLEMENTED();
-  return 1;
+  Value* ea = i.X.RA ? f.Add(f.LoadGPR(i.X.RA), f.LoadGPR(i.X.RB)) : f.LoadGPR(i.X.RB);
+  ea = f.And(ea, f.LoadConstant(~0x1ull));
+  Value* el = f.Shr(f.And(ea, f.LoadConstant(0xFull)), 1);
+  Value* v = f.Extract(f.LoadVR(i.X.RT), el, INT16_TYPE);
+  f.Store(ea, f.ByteSwap(v));
+  return 0;
 }
 
 int InstrEmit_stvewx_(PPCFunctionBuilder& f, InstrData& i, uint32_t vd, uint32_t ra, uint32_t rb) {
-  XEINSTRNOTIMPLEMENTED();
-  return 1;
+  Value* ea = ra ? f.Add(f.LoadGPR(ra), f.LoadGPR(rb)) : f.LoadGPR(rb);
+  ea = f.And(ea, f.LoadConstant(~0x3ull));
+  Value* el = f.Shr(f.And(ea, f.LoadConstant(0xFull)), 2);
+  Value* v = f.Extract(f.LoadVR(vd), el, INT32_TYPE);
+  f.Store(ea, f.ByteSwap(v));
+  return 0;
 }
 XEEMITTER(stvewx,         0x7C00018E, X   )(PPCFunctionBuilder& f, InstrData& i) {
   return InstrEmit_stvewx_(f, i, i.X.RT, i.X.RA, i.X.RB);
@@ -1608,7 +1619,7 @@ XEEMITTER(vupkd3d128,     VX128_3(6, 2032), VX128_3)(PPCFunctionBuilder& f, Inst
       // zzzzZZZZzzzzARGB
       v = f.LoadVR(vb);
       // 0zzzZZZZzzzzARGB
-      v = f.Insert(v, 0, f.LoadConstant((int8_t)0));
+      v = f.Insert(v, 0ull, f.LoadConstant((int8_t)0));
       // 000R000G000B000A
       vec128_t shuf_v = { 0 };
       shuf_v.b16[3] = 13;
diff --git a/src/alloy/hir/function_builder.cc b/src/alloy/hir/function_builder.cc
index e892fcbeb..eb3750b20 100644
--- a/src/alloy/hir/function_builder.cc
+++ b/src/alloy/hir/function_builder.cc
@@ -1479,30 +1479,40 @@ Value* FunctionBuilder::CountLeadingZeros(Value* value) {
   return i->dest;
 }
 
-Value* FunctionBuilder::Insert(Value* value, uint32_t index, Value* part) {
+Value* FunctionBuilder::Insert(Value* value, Value* index, Value* part) {
   // TODO(benvanik): could do some of this as constants.
 
   Instr* i = AppendInstr(
       OPCODE_INSERT_info, 0,
       AllocValue(value->type));
   i->set_src1(value);
-  i->src2.offset = index;
+  i->set_src2(ZeroExtend(index, INT64_TYPE));
   i->set_src3(part);
   return i->dest;
 }
 
-Value* FunctionBuilder::Extract(Value* value, uint32_t index, TypeName target_type) {
+Value* FunctionBuilder::Insert(Value* value, uint64_t index, Value* part) {
+  return Insert(value, LoadConstant(index), part);
+}
+
+Value* FunctionBuilder::Extract(Value* value, Value* index,
+                                TypeName target_type) {
   // TODO(benvanik): could do some of this as constants.
 
   Instr* i = AppendInstr(
       OPCODE_EXTRACT_info, 0,
       AllocValue(target_type));
   i->set_src1(value);
-  i->src2.offset = index;
+  i->set_src2(ZeroExtend(index, INT64_TYPE));
   i->src3.value = NULL;
   return i->dest;
 }
 
+Value* FunctionBuilder::Extract(Value* value, uint64_t index,
+                                TypeName target_type) {
+  return Extract(value, LoadConstant(index), target_type);
+}
+
 Value* FunctionBuilder::Splat(Value* value, TypeName target_type) {
   // TODO(benvanik): could do some of this as constants.
 
diff --git a/src/alloy/hir/function_builder.h b/src/alloy/hir/function_builder.h
index cae613f5b..62647542c 100644
--- a/src/alloy/hir/function_builder.h
+++ b/src/alloy/hir/function_builder.h
@@ -183,8 +183,10 @@ public:
   Value* RotateLeft(Value* value1, Value* value2);
   Value* ByteSwap(Value* value);
   Value* CountLeadingZeros(Value* value);
-  Value* Insert(Value* value, uint32_t index, Value* part);
-  Value* Extract(Value* value, uint32_t index, TypeName target_type);
+  Value* Insert(Value* value, Value* index, Value* part);
+  Value* Insert(Value* value, uint64_t index, Value* part);
+  Value* Extract(Value* value, Value* index, TypeName target_type);
+  Value* Extract(Value* value, uint64_t index, TypeName target_type);
   // i8->i16/i32/... (i8|i8 / i8|i8|i8|i8 / ...)
   // i8/i16/i32 -> vec128
   Value* Splat(Value* value, TypeName target_type);
diff --git a/src/alloy/hir/opcodes.inl b/src/alloy/hir/opcodes.inl
index 660ec25fd..b3b8f8250 100644
--- a/src/alloy/hir/opcodes.inl
+++ b/src/alloy/hir/opcodes.inl
@@ -508,13 +508,13 @@ DEFINE_OPCODE(
 DEFINE_OPCODE(
     OPCODE_INSERT,
     "insert",
-    OPCODE_SIG_V_V_O_V,
+    OPCODE_SIG_V_V_V_V,
     0);
 
 DEFINE_OPCODE(
     OPCODE_EXTRACT,
     "extract",
-    OPCODE_SIG_V_V_O,
+    OPCODE_SIG_V_V_V,
     0);
 
 DEFINE_OPCODE(