[WebAssembly] Use named operands to identify loads and stores

Summary:
Uses the named operands tablegen feature to look up the indices of
offset, address, and p2align operands for all load and store
instructions. This replaces brittle, incorrect logic for identifying
loads and store when eliminating frame indices, which previously
crashed on bulk-memory ops. It also cleans up the SetP2Alignment pass.

Reviewers: aheejin, dschuff

Subscribers: sbc100, jgravelle-google, hiraditya, sunfish, jfb, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D59007

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@355770 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyMCTargetDesc.h b/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyMCTargetDesc.h
index faa8c69baa4b92215ecc09ceca6978e7518f9b21..5db7291031547e289913c059d8c15e348c41b87d 100644 (file)
--- a/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyMCTargetDesc.h
+++ b/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyMCTargetDesc.h
@@ -331,14 +331,6 @@ inline unsigned GetDefaultP2Align(unsigned Opcode) {
   }
 }
 
-/// The operand number of the load or store address in load/store instructions.
-static const unsigned LoadAddressOperandNo = 3;
-static const unsigned StoreAddressOperandNo = 2;
-
-/// The operand number of the load or store p2align in load/store instructions.
-static const unsigned LoadP2AlignOperandNo = 1;
-static const unsigned StoreP2AlignOperandNo = 0;
-
 /// This is used to indicate block signatures.
 enum class ExprType : unsigned {
   Void = 0x40,

diff --git a/lib/Target/WebAssembly/WebAssemblyInstrAtomics.td b/lib/Target/WebAssembly/WebAssemblyInstrAtomics.td
index 89ea8def27fc67b1e122509c73b778532774cd4b..f0cb0c284bf2be986b5d8ad369676b752a16ce8b 100644 (file)
--- a/lib/Target/WebAssembly/WebAssemblyInstrAtomics.td
+++ b/lib/Target/WebAssembly/WebAssemblyInstrAtomics.td
@@ -11,6 +11,7 @@
 ///
 //===----------------------------------------------------------------------===//
 
+let UseNamedOperandTable = 1 in
 multiclass ATOMIC_I<dag oops_r, dag iops_r, dag oops_s, dag iops_s,
                     list<dag> pattern_r, string asmstr_r = "",
                     string asmstr_s = "", bits<32> atomic_op = -1> {
@@ -810,9 +811,9 @@ multiclass WebAssemblyTerRMW<WebAssemblyRegClass rc, string name,
   defm "" :
     ATOMIC_I<(outs rc:$dst),
              (ins P2Align:$p2align, offset32_op:$off, I32:$addr, rc:$exp,
-                  rc:$new),
+                  rc:$new_),
              (outs), (ins P2Align:$p2align, offset32_op:$off), [],
-             !strconcat(name, "\t$dst, ${off}(${addr})${p2align}, $exp, $new"),
+             !strconcat(name, "\t$dst, ${off}(${addr})${p2align}, $exp, $new_"),
              !strconcat(name, "\t${off}${p2align}"), atomic_op>;
 }
 

diff --git a/lib/Target/WebAssembly/WebAssemblyInstrInfo.cpp b/lib/Target/WebAssembly/WebAssemblyInstrInfo.cpp
index 995dc88bb333f4b98ba0b989abe01b346f9c1083..a7c120963e010fbfd9dfdd3ba6360565c1a4af85 100644 (file)
--- a/lib/Target/WebAssembly/WebAssemblyInstrInfo.cpp
+++ b/lib/Target/WebAssembly/WebAssemblyInstrInfo.cpp
@@ -27,6 +27,10 @@ using namespace llvm;
 #define GET_INSTRINFO_CTOR_DTOR
 #include "WebAssemblyGenInstrInfo.inc"
 
+// defines WebAssembly::getNamedOperandIdx
+#define GET_INSTRINFO_NAMED_OPS
+#include "WebAssemblyGenInstrInfo.inc"
+
 WebAssemblyInstrInfo::WebAssemblyInstrInfo(const WebAssemblySubtarget &STI)
     : WebAssemblyGenInstrInfo(WebAssembly::ADJCALLSTACKDOWN,
                               WebAssembly::ADJCALLSTACKUP,

diff --git a/lib/Target/WebAssembly/WebAssemblyInstrInfo.h b/lib/Target/WebAssembly/WebAssemblyInstrInfo.h
index 20eec684b7705fec648f0493819101dde063ab72..df1051b4f42cf931cb3f4355e0c5729262ac7054 100644 (file)
--- a/lib/Target/WebAssembly/WebAssemblyInstrInfo.h
+++ b/lib/Target/WebAssembly/WebAssemblyInstrInfo.h
@@ -21,8 +21,17 @@
 #define GET_INSTRINFO_HEADER
 #include "WebAssemblyGenInstrInfo.inc"
 
+#define GET_INSTRINFO_OPERAND_ENUM
+#include "WebAssemblyGenInstrInfo.inc"
+
 namespace llvm {
 
+namespace WebAssembly {
+
+int16_t getNamedOperandIdx(uint16_t Opcode, uint16_t NamedIndex);
+
+}
+
 class WebAssemblySubtarget;
 
 class WebAssemblyInstrInfo final : public WebAssemblyGenInstrInfo {

diff --git a/lib/Target/WebAssembly/WebAssemblyInstrMemory.td b/lib/Target/WebAssembly/WebAssemblyInstrMemory.td
index 2070f8ad82287f79f6a25dcaba9797e1efe095b3..0d6d12f49ca2916ca6e2bf1ee398c023f5fe3388 100644 (file)
--- a/lib/Target/WebAssembly/WebAssemblyInstrMemory.td
+++ b/lib/Target/WebAssembly/WebAssemblyInstrMemory.td
@@ -52,7 +52,7 @@ def regPlusGA : PatFrag<(ops node:$addr, node:$off),
 
 // Defines atomic and non-atomic loads, regular and extending.
 multiclass WebAssemblyLoad<WebAssemblyRegClass rc, string Name, int Opcode> {
-  let mayLoad = 1 in
+  let mayLoad = 1, UseNamedOperandTable = 1 in
   defm "": I<(outs rc:$dst),
              (ins P2Align:$p2align, offset32_op:$off, I32:$addr),
              (outs), (ins P2Align:$p2align, offset32_op:$off),
@@ -294,7 +294,7 @@ def : LoadPatExternSymOffOnly<i64, extloadi32, LOAD32_U_I64>;
 
 // Defines atomic and non-atomic stores, regular and truncating
 multiclass WebAssemblyStore<WebAssemblyRegClass rc, string Name, int Opcode> {
-  let mayStore = 1 in
+  let mayStore = 1, UseNamedOperandTable = 1 in
   defm "" : I<(outs),
               (ins P2Align:$p2align, offset32_op:$off, I32:$addr, rc:$val),
               (outs),

diff --git a/lib/Target/WebAssembly/WebAssemblyInstrSIMD.td b/lib/Target/WebAssembly/WebAssemblyInstrSIMD.td
index 8169e6a6233f05528e2f0cf145ef00811f4eff62..0d0948c00e05de26d4d3698fb78e6e5703faba09 100644 (file)
--- a/lib/Target/WebAssembly/WebAssemblyInstrSIMD.td
+++ b/lib/Target/WebAssembly/WebAssemblyInstrSIMD.td
@@ -41,12 +41,12 @@ def LaneIdx#SIZE : ImmLeaf<i32, "return 0 <= Imm && Imm < "#SIZE#";">;
 
 // Load: v128.load
 multiclass SIMDLoad<ValueType vec_t> {
-  let mayLoad = 1 in
+  let mayLoad = 1, UseNamedOperandTable = 1 in
   defm LOAD_#vec_t :
-    SIMD_I<(outs V128:$dst), (ins P2Align:$align, offset32_op:$off, I32:$addr),
-           (outs), (ins P2Align:$align, offset32_op:$off), [],
-           "v128.load\t$dst, ${off}(${addr})$align",
-           "v128.load\t$off$align", 0>;
+    SIMD_I<(outs V128:$dst), (ins P2Align:$p2align, offset32_op:$off, I32:$addr),
+           (outs), (ins P2Align:$p2align, offset32_op:$off), [],
+           "v128.load\t$dst, ${off}(${addr})$p2align",
+           "v128.load\t$off$p2align", 0>;
 }
 
 foreach vec_t = [v16i8, v8i16, v4i32, v2i64, v4f32, v2f64] in {
@@ -65,12 +65,12 @@ def : LoadPatExternSymOffOnly<vec_t, load, !cast<NI>("LOAD_"#vec_t)>;
 
 // Store: v128.store
 multiclass SIMDStore<ValueType vec_t> {
-  let mayStore = 1 in
+  let mayStore = 1, UseNamedOperandTable = 1 in
   defm STORE_#vec_t :
-    SIMD_I<(outs), (ins P2Align:$align, offset32_op:$off, I32:$addr, V128:$vec),
-           (outs), (ins P2Align:$align, offset32_op:$off), [],
-           "v128.store\t${off}(${addr})$align, $vec",
-           "v128.store\t$off$align", 1>;
+    SIMD_I<(outs), (ins P2Align:$p2align, offset32_op:$off, I32:$addr, V128:$vec),
+           (outs), (ins P2Align:$p2align, offset32_op:$off), [],
+           "v128.store\t${off}(${addr})$p2align, $vec",
+           "v128.store\t$off$p2align", 1>;
 }
 
 foreach vec_t = [v16i8, v8i16, v4i32, v2i64, v4f32, v2f64] in {

diff --git a/lib/Target/WebAssembly/WebAssemblyRegisterInfo.cpp b/lib/Target/WebAssembly/WebAssemblyRegisterInfo.cpp
index ae808dd6597de91fe32b092013da95d0d208441a..d0002d9e10f295d9540caeb1876d6c8637363ca9 100644 (file)
--- a/lib/Target/WebAssembly/WebAssemblyRegisterInfo.cpp
+++ b/lib/Target/WebAssembly/WebAssemblyRegisterInfo.cpp
@@ -70,13 +70,16 @@ void WebAssemblyRegisterInfo::eliminateFrameIndex(
 
   // If this is the address operand of a load or store, make it relative to SP
   // and fold the frame offset directly in.
-  if ((MI.mayLoad() && FIOperandNum == WebAssembly::LoadAddressOperandNo) ||
-      (MI.mayStore() && FIOperandNum == WebAssembly::StoreAddressOperandNo)) {
-    assert(FrameOffset >= 0 && MI.getOperand(FIOperandNum - 1).getImm() >= 0);
-    int64_t Offset = MI.getOperand(FIOperandNum - 1).getImm() + FrameOffset;
+  unsigned AddrOperandNum = WebAssembly::getNamedOperandIdx(
+      MI.getOpcode(), WebAssembly::OpName::addr);
+  if (AddrOperandNum == FIOperandNum) {
+    unsigned OffsetOperandNum = WebAssembly::getNamedOperandIdx(
+        MI.getOpcode(), WebAssembly::OpName::off);
+    assert(FrameOffset >= 0 && MI.getOperand(OffsetOperandNum).getImm() >= 0);
+    int64_t Offset = MI.getOperand(OffsetOperandNum).getImm() + FrameOffset;
 
     if (static_cast<uint64_t>(Offset) <= std::numeric_limits<uint32_t>::max()) {
-      MI.getOperand(FIOperandNum - 1).setImm(Offset);
+      MI.getOperand(OffsetOperandNum).setImm(Offset);
       MI.getOperand(FIOperandNum)
           .ChangeToRegister(FrameRegister, /*IsDef=*/false);
       return;

diff --git a/lib/Target/WebAssembly/WebAssemblySetP2AlignOperands.cpp b/lib/Target/WebAssembly/WebAssemblySetP2AlignOperands.cpp
index 68ab925e433080a4d252262e5d2213167d700158..a249ccf1763865e648a0ab28fce020cf4987b9b9 100644 (file)
--- a/lib/Target/WebAssembly/WebAssemblySetP2AlignOperands.cpp
+++ b/lib/Target/WebAssembly/WebAssemblySetP2AlignOperands.cpp
@@ -13,6 +13,7 @@
 
 #include "MCTargetDesc/WebAssemblyMCTargetDesc.h"
 #include "WebAssembly.h"
+#include "WebAssemblyInstrInfo.h"
 #include "WebAssemblyMachineFunctionInfo.h"
 #include "llvm/CodeGen/MachineBlockFrequencyInfo.h"
 #include "llvm/CodeGen/MachineMemOperand.h"
@@ -83,114 +84,11 @@ bool WebAssemblySetP2AlignOperands::runOnMachineFunction(MachineFunction &MF) {
 
   for (auto &MBB : MF) {
     for (auto &MI : MBB) {
-      switch (MI.getOpcode()) {
-      case WebAssembly::LOAD_I32:
-      case WebAssembly::LOAD_I64:
-      case WebAssembly::LOAD_F32:
-      case WebAssembly::LOAD_F64:
-      case WebAssembly::LOAD_v16i8:
-      case WebAssembly::LOAD_v8i16:
-      case WebAssembly::LOAD_v4i32:
-      case WebAssembly::LOAD_v2i64:
-      case WebAssembly::LOAD_v4f32:
-      case WebAssembly::LOAD_v2f64:
-      case WebAssembly::LOAD8_S_I32:
-      case WebAssembly::LOAD8_U_I32:
-      case WebAssembly::LOAD16_S_I32:
-      case WebAssembly::LOAD16_U_I32:
-      case WebAssembly::LOAD8_S_I64:
-      case WebAssembly::LOAD8_U_I64:
-      case WebAssembly::LOAD16_S_I64:
-      case WebAssembly::LOAD16_U_I64:
-      case WebAssembly::LOAD32_S_I64:
-      case WebAssembly::LOAD32_U_I64:
-      case WebAssembly::ATOMIC_LOAD_I32:
-      case WebAssembly::ATOMIC_LOAD8_U_I32:
-      case WebAssembly::ATOMIC_LOAD16_U_I32:
-      case WebAssembly::ATOMIC_LOAD_I64:
-      case WebAssembly::ATOMIC_LOAD8_U_I64:
-      case WebAssembly::ATOMIC_LOAD16_U_I64:
-      case WebAssembly::ATOMIC_LOAD32_U_I64:
-      case WebAssembly::ATOMIC_RMW8_U_ADD_I32:
-      case WebAssembly::ATOMIC_RMW8_U_ADD_I64:
-      case WebAssembly::ATOMIC_RMW8_U_SUB_I32:
-      case WebAssembly::ATOMIC_RMW8_U_SUB_I64:
-      case WebAssembly::ATOMIC_RMW8_U_AND_I32:
-      case WebAssembly::ATOMIC_RMW8_U_AND_I64:
-      case WebAssembly::ATOMIC_RMW8_U_OR_I32:
-      case WebAssembly::ATOMIC_RMW8_U_OR_I64:
-      case WebAssembly::ATOMIC_RMW8_U_XOR_I32:
-      case WebAssembly::ATOMIC_RMW8_U_XOR_I64:
-      case WebAssembly::ATOMIC_RMW8_U_XCHG_I32:
-      case WebAssembly::ATOMIC_RMW8_U_XCHG_I64:
-      case WebAssembly::ATOMIC_RMW8_U_CMPXCHG_I32:
-      case WebAssembly::ATOMIC_RMW8_U_CMPXCHG_I64:
-      case WebAssembly::ATOMIC_RMW16_U_ADD_I32:
-      case WebAssembly::ATOMIC_RMW16_U_ADD_I64:
-      case WebAssembly::ATOMIC_RMW16_U_SUB_I32:
-      case WebAssembly::ATOMIC_RMW16_U_SUB_I64:
-      case WebAssembly::ATOMIC_RMW16_U_AND_I32:
-      case WebAssembly::ATOMIC_RMW16_U_AND_I64:
-      case WebAssembly::ATOMIC_RMW16_U_OR_I32:
-      case WebAssembly::ATOMIC_RMW16_U_OR_I64:
-      case WebAssembly::ATOMIC_RMW16_U_XOR_I32:
-      case WebAssembly::ATOMIC_RMW16_U_XOR_I64:
-      case WebAssembly::ATOMIC_RMW16_U_XCHG_I32:
-      case WebAssembly::ATOMIC_RMW16_U_XCHG_I64:
-      case WebAssembly::ATOMIC_RMW16_U_CMPXCHG_I32:
-      case WebAssembly::ATOMIC_RMW16_U_CMPXCHG_I64:
-      case WebAssembly::ATOMIC_RMW_ADD_I32:
-      case WebAssembly::ATOMIC_RMW32_U_ADD_I64:
-      case WebAssembly::ATOMIC_RMW_SUB_I32:
-      case WebAssembly::ATOMIC_RMW32_U_SUB_I64:
-      case WebAssembly::ATOMIC_RMW_AND_I32:
-      case WebAssembly::ATOMIC_RMW32_U_AND_I64:
-      case WebAssembly::ATOMIC_RMW_OR_I32:
-      case WebAssembly::ATOMIC_RMW32_U_OR_I64:
-      case WebAssembly::ATOMIC_RMW_XOR_I32:
-      case WebAssembly::ATOMIC_RMW32_U_XOR_I64:
-      case WebAssembly::ATOMIC_RMW_XCHG_I32:
-      case WebAssembly::ATOMIC_RMW32_U_XCHG_I64:
-      case WebAssembly::ATOMIC_RMW_CMPXCHG_I32:
-      case WebAssembly::ATOMIC_RMW32_U_CMPXCHG_I64:
-      case WebAssembly::ATOMIC_RMW_ADD_I64:
-      case WebAssembly::ATOMIC_RMW_SUB_I64:
-      case WebAssembly::ATOMIC_RMW_AND_I64:
-      case WebAssembly::ATOMIC_RMW_OR_I64:
-      case WebAssembly::ATOMIC_RMW_XOR_I64:
-      case WebAssembly::ATOMIC_RMW_XCHG_I64:
-      case WebAssembly::ATOMIC_RMW_CMPXCHG_I64:
-      case WebAssembly::ATOMIC_NOTIFY:
-      case WebAssembly::ATOMIC_WAIT_I32:
-      case WebAssembly::ATOMIC_WAIT_I64:
-        rewriteP2Align(MI, WebAssembly::LoadP2AlignOperandNo);
-        break;
-      case WebAssembly::STORE_I32:
-      case WebAssembly::STORE_I64:
-      case WebAssembly::STORE_F32:
-      case WebAssembly::STORE_F64:
-      case WebAssembly::STORE_v16i8:
-      case WebAssembly::STORE_v8i16:
-      case WebAssembly::STORE_v4i32:
-      case WebAssembly::STORE_v2i64:
-      case WebAssembly::STORE_v4f32:
-      case WebAssembly::STORE_v2f64:
-      case WebAssembly::STORE8_I32:
-      case WebAssembly::STORE16_I32:
-      case WebAssembly::STORE8_I64:
-      case WebAssembly::STORE16_I64:
-      case WebAssembly::STORE32_I64:
-      case WebAssembly::ATOMIC_STORE_I32:
-      case WebAssembly::ATOMIC_STORE8_I32:
-      case WebAssembly::ATOMIC_STORE16_I32:
-      case WebAssembly::ATOMIC_STORE_I64:
-      case WebAssembly::ATOMIC_STORE8_I64:
-      case WebAssembly::ATOMIC_STORE16_I64:
-      case WebAssembly::ATOMIC_STORE32_I64:
-        rewriteP2Align(MI, WebAssembly::StoreP2AlignOperandNo);
-        break;
-      default:
-        break;
+      int16_t P2AlignOpNum = WebAssembly::getNamedOperandIdx(
+          MI.getOpcode(), WebAssembly::OpName::p2align);
+      if (P2AlignOpNum != -1) {
+        rewriteP2Align(MI, P2AlignOpNum);
+        Changed = true;
       }
     }
   }

diff --git a/test/CodeGen/WebAssembly/bulk-memory.ll b/test/CodeGen/WebAssembly/bulk-memory.ll
index b7b34bdfdcd3f937a6bbdb3eb68cc94748b28df5..6574511089b74c84103dd4914e88d2cc77e46ddf 100644 (file)
--- a/test/CodeGen/WebAssembly/bulk-memory.ll
+++ b/test/CodeGen/WebAssembly/bulk-memory.ll
@@ -140,3 +140,68 @@ define void @memset_1024(i8* %dest, i8 %val) {
   call void @llvm.memset.p0i8.i32(i8* %dest, i8 %val, i32 1024, i1 0)
   ret void
 }
+
+; The following tests check that frame index elimination works for
+; bulk memory instructions. The stack pointer is bumped by 16 instead
+; of 10 because the stack pointer in WebAssembly is currently always
+; 16-byte aligned, even in leaf functions, although it is not written
+; back to the global in this case.
+
+; TODO: Change TransientStackAlignment to 1 to avoid this extra
+; arithmetic. This will require forcing the use of StackAlignment in
+; PrologEpilogEmitter.cpp when
+; WebAssemblyFrameLowering::needsSPWriteback would be true.
+
+; CHECK-LABEL: memcpy_alloca_src:
+; NO-BULK-MEM-NOT: memory.copy
+; BULK-MEM-NEXT: .functype memcpy_alloca_src (i32) -> ()
+; BULK-MEM-NEXT: global.get $push[[L0:[0-9]+]]=, __stack_pointer
+; BULK-MEM-NEXT: i32.const $push[[L1:[0-9]+]]=, 16
+; BULK-MEM-NEXT: i32.sub $push[[L2:[0-9]+]]=, $pop[[L0]], $pop[[L1]]
+; BULK-MEM-NEXT: i32.const $push[[L3:[0-9]+]]=, 6
+; BULK-MEM-NEXT: i32.add $push[[L4:[0-9]+]]=, $pop[[L2]], $pop[[L3]]
+; BULK-MEM-NEXT: i32.const $push[[L5:[0-9]+]]=, 10
+; BULK-MEM-NEXT: memory.copy 0, 0, $0, $pop[[L4]], $pop[[L5]]
+; BULK-MEM-NEXT: return
+define void @memcpy_alloca_src(i8* %dst) {
+  %a = alloca [10 x i8]
+  %p = bitcast [10 x i8]* %a to i8*
+  call void @llvm.memcpy.p0i8.p0i8.i32(i8* %dst, i8* %p, i32 10, i1 false)
+  ret void
+}
+
+; CHECK-LABEL: memcpy_alloca_dst:
+; NO-BULK-MEM-NOT: memory.copy
+; BULK-MEM-NEXT: .functype memcpy_alloca_dst (i32) -> ()
+; BULK-MEM-NEXT: global.get $push[[L0:[0-9]+]]=, __stack_pointer
+; BULK-MEM-NEXT: i32.const $push[[L1:[0-9]+]]=, 16
+; BULK-MEM-NEXT: i32.sub $push[[L2:[0-9]+]]=, $pop[[L0]], $pop[[L1]]
+; BULK-MEM-NEXT: i32.const $push[[L3:[0-9]+]]=, 6
+; BULK-MEM-NEXT: i32.add $push[[L4:[0-9]+]]=, $pop[[L2]], $pop[[L3]]
+; BULK-MEM-NEXT: i32.const $push[[L5:[0-9]+]]=, 10
+; BULK-MEM-NEXT: memory.copy 0, 0, $pop[[L4]], $0, $pop[[L5]]
+; BULK-MEM-NEXT: return
+define void @memcpy_alloca_dst(i8* %src) {
+  %a = alloca [10 x i8]
+  %p = bitcast [10 x i8]* %a to i8*
+  call void @llvm.memcpy.p0i8.p0i8.i32(i8* %p, i8* %src, i32 10, i1 false)
+  ret void
+}
+
+; CHECK-LABEL: memset_alloca:
+; NO-BULK-MEM-NOT: memory.fill
+; BULK-MEM-NEXT: .functype memset_alloca (i32) -> ()
+; BULK-MEM-NEXT: global.get $push[[L0:[0-9]+]]=, __stack_pointer
+; BULK-MEM-NEXT: i32.const $push[[L1:[0-9]+]]=, 16
+; BULK-MEM-NEXT: i32.sub $push[[L2:[0-9]+]]=, $pop[[L0]], $pop[[L1]]
+; BULK-MEM-NEXT: i32.const $push[[L3:[0-9]+]]=, 6
+; BULK-MEM-NEXT: i32.add $push[[L4:[0-9]+]]=, $pop[[L2]], $pop[[L3]]
+; BULK-MEM-NEXT: i32.const $push[[L5:[0-9]+]]=, 10
+; BULK-MEM-NEXT: memory.fill 0, $pop[[L4]], $0, $pop[[L5]]
+; BULK-MEM-NEXT: return
+define void @memset_alloca(i8 %val) {
+  %a = alloca [10 x i8]
+  %p = bitcast [10 x i8]* %a to i8*
+  call void @llvm.memset.p0i8.i32(i8* %p, i8 %val, i32 10, i1 false)
+  ret void
+}