[WebAssembly] Implement ReverseBranchCondition, and re-enable MachineBlockPlacement

This patch introduces a codegen-only instruction currently named br_unless,
which makes it convenient to implement ReverseBranchCondition and re-enable
the MachineBlockPlacement pass. Then in a late pass, it lowers br_unless
back into br_if.

Differential Revision: http://reviews.llvm.org/D14995

llvm-svn: 254826
This commit is contained in:
Dan Gohman 2015-12-05 03:03:35 +00:00
parent 064a672f65
commit f0b165a7f8
10 changed files with 321 additions and 45 deletions

View File

@ -18,6 +18,7 @@ add_llvm_target(WebAssemblyCodeGen
WebAssemblyISelDAGToDAG.cpp
WebAssemblyISelLowering.cpp
WebAssemblyInstrInfo.cpp
WebAssemblyLowerBrUnless.cpp
WebAssemblyMachineFunctionInfo.cpp
WebAssemblyMCInstLower.cpp
WebAssemblyOptimizeReturned.cpp

View File

@ -32,6 +32,7 @@ FunctionPass *createWebAssemblyStoreResults();
FunctionPass *createWebAssemblyRegStackify();
FunctionPass *createWebAssemblyRegColoring();
FunctionPass *createWebAssemblyCFGStackify();
FunctionPass *createWebAssemblyLowerBrUnless();
FunctionPass *createWebAssemblyRegNumbering();
FunctionPass *createWebAssemblyPeephole();

View File

@ -15,9 +15,13 @@
let Defs = [ARGUMENTS] in {
let isBranch = 1, isTerminator = 1, hasCtrlDep = 1 in {
def BR_IF : I<(outs), (ins I32:$a, bb_op:$dst),
[(brcond I32:$a, bb:$dst)],
"br_if \t$a, $dst">;
// The condition operand is a boolean value which WebAssembly represents as i32.
def BR_IF : I<(outs), (ins I32:$cond, bb_op:$dst),
[(brcond I32:$cond, bb:$dst)],
"br_if \t$cond, $dst">;
let isCodeGenOnly = 1 in
def BR_UNLESS : I<(outs), (ins I32:$cond, bb_op:$dst), [],
"br_unless\t$cond, $dst">;
let isBarrier = 1 in {
def BR : I<(outs), (ins bb_op:$dst),
[(br bb:$dst)],
@ -25,6 +29,15 @@ def BR : I<(outs), (ins bb_op:$dst),
} // isBarrier = 1
} // isBranch = 1, isTerminator = 1, hasCtrlDep = 1
} // Defs = [ARGUMENTS]
def : Pat<(brcond (i32 (setne I32:$cond, 0)), bb:$dst),
(BR_IF I32:$cond, bb_op:$dst)>;
def : Pat<(brcond (i32 (seteq I32:$cond, 0)), bb:$dst),
(BR_UNLESS I32:$cond, bb_op:$dst)>;
let Defs = [ARGUMENTS] in {
// TODO: SelectionDAG's lowering insists on using a pointer as the index for
// jump tables, so in practice we don't ever use TABLESWITCH_I64 in wasm32 mode
// currently.

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@ -71,6 +71,15 @@ bool WebAssemblyInstrInfo::AnalyzeBranch(MachineBasicBlock &MBB,
case WebAssembly::BR_IF:
if (HaveCond)
return true;
Cond.push_back(MachineOperand::CreateImm(true));
Cond.push_back(MI.getOperand(0));
TBB = MI.getOperand(1).getMBB();
HaveCond = true;
break;
case WebAssembly::BR_UNLESS:
if (HaveCond)
return true;
Cond.push_back(MachineOperand::CreateImm(false));
Cond.push_back(MI.getOperand(0));
TBB = MI.getOperand(1).getMBB();
HaveCond = true;
@ -113,8 +122,6 @@ unsigned WebAssemblyInstrInfo::InsertBranch(MachineBasicBlock &MBB,
MachineBasicBlock *FBB,
ArrayRef<MachineOperand> Cond,
DebugLoc DL) const {
assert(Cond.size() <= 1);
if (Cond.empty()) {
if (!TBB)
return 0;
@ -123,7 +130,17 @@ unsigned WebAssemblyInstrInfo::InsertBranch(MachineBasicBlock &MBB,
return 1;
}
BuildMI(&MBB, DL, get(WebAssembly::BR_IF)).addOperand(Cond[0]).addMBB(TBB);
assert(Cond.size() == 2 && "Expected a flag and a successor block");
if (Cond[0].getImm()) {
BuildMI(&MBB, DL, get(WebAssembly::BR_IF))
.addOperand(Cond[1])
.addMBB(TBB);
} else {
BuildMI(&MBB, DL, get(WebAssembly::BR_UNLESS))
.addOperand(Cond[1])
.addMBB(TBB);
}
if (!FBB)
return 1;
@ -133,10 +150,7 @@ unsigned WebAssemblyInstrInfo::InsertBranch(MachineBasicBlock &MBB,
bool WebAssemblyInstrInfo::ReverseBranchCondition(
SmallVectorImpl<MachineOperand> &Cond) const {
assert(Cond.size() == 1);
// TODO: Add branch reversal here... And re-enable MachineBlockPlacementID
// when we do.
return true;
assert(Cond.size() == 2 && "Expected a flag and a successor block");
Cond.front() = MachineOperand::CreateImm(!Cond.front().getImm());
return false;
}

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@ -0,0 +1,133 @@
//===-- WebAssemblyLowerBrUnless.cpp - Lower br_unless --------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
///
/// \file
/// \brief This file lowers br_unless into br_if with an inverted condition.
///
/// br_unless is not currently in the spec, but it's very convenient for LLVM
/// to use. This pass allows LLVM to use it, for now.
///
//===----------------------------------------------------------------------===//
#include "WebAssembly.h"
#include "WebAssemblyMachineFunctionInfo.h"
#include "WebAssemblySubtarget.h"
#include "MCTargetDesc/WebAssemblyMCTargetDesc.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
using namespace llvm;
#define DEBUG_TYPE "wasm-lower-br_unless"
namespace {
class WebAssemblyLowerBrUnless final : public MachineFunctionPass {
const char *getPassName() const override {
return "WebAssembly Lower br_unless";
}
void getAnalysisUsage(AnalysisUsage &AU) const override {
AU.setPreservesCFG();
MachineFunctionPass::getAnalysisUsage(AU);
}
bool runOnMachineFunction(MachineFunction &MF) override;
public:
static char ID; // Pass identification, replacement for typeid
WebAssemblyLowerBrUnless() : MachineFunctionPass(ID) {}
};
} // end anonymous namespace
char WebAssemblyLowerBrUnless::ID = 0;
FunctionPass *llvm::createWebAssemblyLowerBrUnless() {
return new WebAssemblyLowerBrUnless();
}
bool WebAssemblyLowerBrUnless::runOnMachineFunction(MachineFunction &MF) {
DEBUG(dbgs() << "********** Lowering br_unless **********\n"
"********** Function: "
<< MF.getName() << '\n');
auto &MFI = *MF.getInfo<WebAssemblyFunctionInfo>();
const auto &TII = *MF.getSubtarget<WebAssemblySubtarget>().getInstrInfo();
auto &MRI = MF.getRegInfo();
for (auto &MBB : MF) {
for (auto MII = MBB.begin(); MII != MBB.end(); ) {
MachineInstr *MI = &*MII++;
if (MI->getOpcode() != WebAssembly::BR_UNLESS)
continue;
unsigned Cond = MI->getOperand(0).getReg();
bool Inverted = false;
// Attempt to invert the condition in place.
if (MFI.isVRegStackified(Cond)) {
assert(MRI.hasOneDef(Cond));
MachineInstr *Def = MRI.getVRegDef(Cond);
switch (Def->getOpcode()) {
using namespace WebAssembly;
case EQ_I32: Def->setDesc(TII.get(NE_I32)); Inverted = true; break;
case NE_I32: Def->setDesc(TII.get(EQ_I32)); Inverted = true; break;
case GT_S_I32: Def->setDesc(TII.get(LE_S_I32)); Inverted = true; break;
case GE_S_I32: Def->setDesc(TII.get(LT_S_I32)); Inverted = true; break;
case LT_S_I32: Def->setDesc(TII.get(GE_S_I32)); Inverted = true; break;
case LE_S_I32: Def->setDesc(TII.get(GT_S_I32)); Inverted = true; break;
case GT_U_I32: Def->setDesc(TII.get(LE_U_I32)); Inverted = true; break;
case GE_U_I32: Def->setDesc(TII.get(LT_U_I32)); Inverted = true; break;
case LT_U_I32: Def->setDesc(TII.get(GE_U_I32)); Inverted = true; break;
case LE_U_I32: Def->setDesc(TII.get(GT_U_I32)); Inverted = true; break;
case EQ_I64: Def->setDesc(TII.get(NE_I64)); Inverted = true; break;
case NE_I64: Def->setDesc(TII.get(EQ_I64)); Inverted = true; break;
case GT_S_I64: Def->setDesc(TII.get(LE_S_I64)); Inverted = true; break;
case GE_S_I64: Def->setDesc(TII.get(LT_S_I64)); Inverted = true; break;
case LT_S_I64: Def->setDesc(TII.get(GE_S_I64)); Inverted = true; break;
case LE_S_I64: Def->setDesc(TII.get(GT_S_I64)); Inverted = true; break;
case GT_U_I64: Def->setDesc(TII.get(LE_U_I64)); Inverted = true; break;
case GE_U_I64: Def->setDesc(TII.get(LT_U_I64)); Inverted = true; break;
case LT_U_I64: Def->setDesc(TII.get(GE_U_I64)); Inverted = true; break;
case LE_U_I64: Def->setDesc(TII.get(GT_U_I64)); Inverted = true; break;
case EQ_F32: Def->setDesc(TII.get(NE_F32)); Inverted = true; break;
case NE_F32: Def->setDesc(TII.get(EQ_F32)); Inverted = true; break;
case EQ_F64: Def->setDesc(TII.get(NE_F64)); Inverted = true; break;
case NE_F64: Def->setDesc(TII.get(EQ_F64)); Inverted = true; break;
default: break;
}
}
// If we weren't able to invert the condition in place. Insert an
// expression to invert it.
if (!Inverted) {
unsigned ZeroReg = MRI.createVirtualRegister(&WebAssembly::I32RegClass);
MFI.stackifyVReg(ZeroReg);
BuildMI(MBB, MI, MI->getDebugLoc(), TII.get(WebAssembly::CONST_I32), ZeroReg)
.addImm(0);
unsigned Tmp = MRI.createVirtualRegister(&WebAssembly::I32RegClass);
MFI.stackifyVReg(Tmp);
BuildMI(MBB, MI, MI->getDebugLoc(), TII.get(WebAssembly::EQ_I32), Tmp)
.addReg(Cond)
.addReg(ZeroReg);
Cond = Tmp;
Inverted = true;
}
// The br_unless condition has now been inverted. Insert a br_if and
// delete the br_unless.
assert(Inverted);
BuildMI(MBB, MI, MI->getDebugLoc(), TII.get(WebAssembly::BR_IF))
.addReg(Cond)
.addMBB(MI->getOperand(1).getMBB());
MBB.erase(MI);
}
}
return true;
}

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@ -64,7 +64,7 @@ bool WebAssemblyPeephole::runOnMachineFunction(MachineFunction &MF) {
// can use $discard instead.
MachineOperand &MO = MI.getOperand(0);
unsigned OldReg = MO.getReg();
if (OldReg == MI.getOperand(2).getReg()) {
if (OldReg == MI.getOperand(3).getReg()) {
unsigned NewReg = MRI.createVirtualRegister(MRI.getRegClass(OldReg));
MO.setReg(NewReg);
MO.setIsDead();

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@ -171,10 +171,6 @@ void WebAssemblyPassConfig::addPostRegAlloc() {
// Fails with: should be run after register allocation.
disablePass(&MachineCopyPropagationID);
// TODO: Until we get ReverseBranchCondition support, MachineBlockPlacement
// can create ugly-looking control flow.
disablePass(&MachineBlockPlacementID);
// Run the register coloring pass to reduce the total number of registers.
addPass(createWebAssemblyRegColoring());
}
@ -183,6 +179,9 @@ void WebAssemblyPassConfig::addPreEmitPass() {
// Put the CFG in structured form; insert BLOCK and LOOP markers.
addPass(createWebAssemblyCFGStackify());
// Lower br_unless into br_if.
addPass(createWebAssemblyLowerBrUnless());
// Create a mapping from LLVM CodeGen virtual registers to wasm registers.
addPass(createWebAssemblyRegNumbering());

View File

@ -1,4 +1,5 @@
; RUN: llc < %s -asm-verbose=false | FileCheck %s
; RUN: llc < %s -asm-verbose=false -disable-block-placement | FileCheck %s
; RUN: llc < %s -asm-verbose=false | FileCheck -check-prefix=OPT %s
; Test the CFG stackifier pass.
@ -12,10 +13,21 @@ declare void @something()
; CHECK-LABEL: test0:
; CHECK: loop
; CHECK: i32.add
; CHECK-NOT: br
; CHECK: br_if
; CHECK-NOT: br
; CHECK: call
; CHECK: br BB0_1{{$}}
; CHECK: return{{$}}
; OPT-LABEL: test0:
; OPT: loop
; OPT: i32.add
; OPT-NOT: br
; OPT: br_if
; OPT-NOT: br
; OPT: call
; OPT: br BB0_1{{$}}
; OPT: return{{$}}
define void @test0(i32 %n) {
entry:
br label %header
@ -40,10 +52,21 @@ back:
; CHECK-LABEL: test1:
; CHECK: loop
; CHECK: i32.add
; CHECK-NOT: br
; CHECK: br_if
; CHECK-NOT: br
; CHECK: call
; CHECK: br BB1_1{{$}}
; CHECK: return{{$}}
; OPT-LABEL: test1:
; OPT: loop
; OPT: i32.add
; OPT-NOT: br
; OPT: br_if
; OPT-NOT: br
; OPT: call
; OPT: br BB1_1{{$}}
; OPT: return{{$}}
define void @test1(i32 %n) {
entry:
br label %header
@ -69,9 +92,16 @@ back:
; CHECK: block BB2_2{{$}}
; CHECK: br_if {{.*}}, BB2_2{{$}}
; CHECK: BB2_1:
; CHECK: br_if $pop{{[0-9]+}}, BB2_1{{$}}
; CHECK: br_if ${{[0-9]+}}, BB2_1{{$}}
; CHECK: BB2_2:
; CHECK: return{{$}}
; OPT-LABEL: test2:
; OPT: block BB2_2{{$}}
; OPT: br_if {{.*}}, BB2_2{{$}}
; OPT: BB2_1:
; OPT: br_if ${{[0-9]+}}, BB2_1{{$}}
; OPT: BB2_2:
; OPT: return{{$}}
define void @test2(double* nocapture %p, i32 %n) {
entry:
%cmp.4 = icmp sgt i32 %n, 0
@ -100,13 +130,23 @@ for.end:
; CHECK-LABEL: doublediamond:
; CHECK: block BB3_5{{$}}
; CHECK: block BB3_2{{$}}
; CHECK: br_if $pop{{[0-9]+}}, BB3_2{{$}}
; CHECK: br_if $0, BB3_2{{$}}
; CHECK: block BB3_4{{$}}
; CHECK: br_if $pop{{[0-9]+}}, BB3_4{{$}}
; CHECK: br_if $1, BB3_4{{$}}
; CHECK: br BB3_5{{$}}
; CHECK: BB3_4:
; CHECK: BB3_5:
; CHECK: return ${{[0-9]+}}{{$}}
; OPT-LABEL: doublediamond:
; OPT: block BB3_5{{$}}
; OPT: block BB3_4{{$}}
; OPT: br_if {{.*}}, BB3_4{{$}}
; OPT: block BB3_3{{$}}
; OPT: br_if {{.*}}, BB3_3{{$}}
; OPT: br BB3_5{{$}}
; OPT: BB3_4:
; OPT: BB3_5:
; OPT: return ${{[0-9]+}}{{$}}
define i32 @doublediamond(i32 %a, i32 %b, i32* %p) {
entry:
%c = icmp eq i32 %a, 0
@ -132,9 +172,14 @@ exit:
; CHECK-LABEL: triangle:
; CHECK: block BB4_2{{$}}
; CHECK: br_if $pop{{[0-9]+}}, BB4_2{{$}}
; CHECK: br_if $1, BB4_2{{$}}
; CHECK: BB4_2:
; CHECK: return ${{[0-9]+}}{{$}}
; OPT-LABEL: triangle:
; OPT: block BB4_2{{$}}
; OPT: br_if $1, BB4_2{{$}}
; OPT: BB4_2:
; OPT: return ${{[0-9]+}}{{$}}
define i32 @triangle(i32* %p, i32 %a) {
entry:
%c = icmp eq i32 %a, 0
@ -151,11 +196,19 @@ exit:
; CHECK-LABEL: diamond:
; CHECK: block BB5_3{{$}}
; CHECK: block BB5_2{{$}}
; CHECK: br_if $pop{{[0-9]+}}, BB5_2{{$}}
; CHECK: br_if $1, BB5_2{{$}}
; CHECK: br BB5_3{{$}}
; CHECK: BB5_2:
; CHECK: BB5_3:
; CHECK: return ${{[0-9]+}}{{$}}
; OPT-LABEL: diamond:
; OPT: block BB5_3{{$}}
; OPT: block BB5_2{{$}}
; OPT: br_if {{.*}}, BB5_2{{$}}
; OPT: br BB5_3{{$}}
; OPT: BB5_2:
; OPT: BB5_3:
; OPT: return ${{[0-9]+}}{{$}}
define i32 @diamond(i32* %p, i32 %a) {
entry:
%c = icmp eq i32 %a, 0
@ -175,6 +228,9 @@ exit:
; CHECK-LABEL: single_block:
; CHECK-NOT: br
; CHECK: return $pop{{[0-9]+}}{{$}}
; OPT-LABEL: single_block:
; OPT-NOT: br
; OPT: return $pop{{[0-9]+}}{{$}}
define i32 @single_block(i32* %p) {
entry:
store volatile i32 0, i32* %p
@ -187,6 +243,12 @@ entry:
; CHECK: i32.store $discard=, 0($0), $pop{{[0-9]+}}{{$}}
; CHECK: br BB7_1{{$}}
; CHECK: BB7_2:
; OPT-LABEL: minimal_loop:
; OPT-NOT: br
; OPT: BB7_1:
; OPT: i32.store $discard=, 0($0), $pop{{[0-9]+}}{{$}}
; OPT: br BB7_1{{$}}
; OPT: BB7_2:
define i32 @minimal_loop(i32* %p) {
entry:
store volatile i32 0, i32* %p
@ -203,6 +265,13 @@ loop:
; CHECK: br_if $pop{{[0-9]+}}, BB8_1{{$}}
; CHECK: BB8_2:
; CHECK: return ${{[0-9]+}}{{$}}
; OPT-LABEL: simple_loop:
; OPT-NOT: br
; OPT: BB8_1:
; OPT: loop BB8_2{{$}}
; OPT: br_if {{.*}}, BB8_1{{$}}
; OPT: BB8_2:
; OPT: return ${{[0-9]+}}{{$}}
define i32 @simple_loop(i32* %p, i32 %a) {
entry:
%c = icmp eq i32 %a, 0
@ -218,12 +287,20 @@ exit:
; CHECK-LABEL: doubletriangle:
; CHECK: block BB9_4{{$}}
; CHECK: br_if $pop{{[0-9]+}}, BB9_4{{$}}
; CHECK: br_if $0, BB9_4{{$}}
; CHECK: block BB9_3{{$}}
; CHECK: br_if $pop{{[0-9]+}}, BB9_3{{$}}
; CHECK: br_if $1, BB9_3{{$}}
; CHECK: BB9_3:
; CHECK: BB9_4:
; CHECK: return ${{[0-9]+}}{{$}}
; OPT-LABEL: doubletriangle:
; OPT: block BB9_4{{$}}
; OPT: br_if $0, BB9_4{{$}}
; OPT: block BB9_3{{$}}
; OPT: br_if $1, BB9_3{{$}}
; OPT: BB9_3:
; OPT: BB9_4:
; OPT: return ${{[0-9]+}}{{$}}
define i32 @doubletriangle(i32 %a, i32 %b, i32* %p) {
entry:
%c = icmp eq i32 %a, 0
@ -247,12 +324,21 @@ exit:
; CHECK-LABEL: ifelse_earlyexits:
; CHECK: block BB10_4{{$}}
; CHECK: block BB10_2{{$}}
; CHECK: br_if $pop{{[0-9]+}}, BB10_2{{$}}
; CHECK: br_if $0, BB10_2{{$}}
; CHECK: br BB10_4{{$}}
; CHECK: BB10_2:
; CHECK: br_if $pop{{[0-9]+}}, BB10_4{{$}}
; CHECK: br_if $1, BB10_4{{$}}
; CHECK: BB10_4:
; CHECK: return ${{[0-9]+}}{{$}}
; OPT-LABEL: ifelse_earlyexits:
; OPT: block BB10_4{{$}}
; OPT: block BB10_3{{$}}
; OPT: br_if {{.*}}, BB10_3{{$}}
; OPT: br_if $1, BB10_4{{$}}
; OPT: br BB10_4{{$}}
; OPT: BB10_3:
; OPT: BB10_4:
; OPT: return ${{[0-9]+}}{{$}}
define i32 @ifelse_earlyexits(i32 %a, i32 %b, i32* %p) {
entry:
%c = icmp eq i32 %a, 0
@ -278,16 +364,31 @@ exit:
; CHECK: loop BB11_7{{$}}
; CHECK: block BB11_6{{$}}
; CHECK: block BB11_3{{$}}
; CHECK: br_if $pop{{.*}}, BB11_3{{$}}
; CHECK: br_if $0, BB11_3{{$}}
; CHECK: br BB11_6{{$}}
; CHECK: BB11_3:
; CHECK: block BB11_5{{$}}
; CHECK: br_if $pop{{.*}}, BB11_5{{$}}
; CHECK: br_if $1, BB11_5{{$}}
; CHECK: br BB11_6{{$}}
; CHECK: BB11_5:
; CHECK: BB11_6:
; CHECK: br BB11_1{{$}}
; CHECK: BB11_7:
; OPT-LABEL: doublediamond_in_a_loop:
; OPT: BB11_1:
; OPT: loop BB11_7{{$}}
; OPT: block BB11_6{{$}}
; OPT: block BB11_5{{$}}
; OPT: br_if {{.*}}, BB11_5{{$}}
; OPT: block BB11_4{{$}}
; OPT: br_if {{.*}}, BB11_4{{$}}
; OPT: br BB11_6{{$}}
; OPT: BB11_4:
; OPT: br BB11_6{{$}}
; OPT: BB11_5:
; OPT: BB11_6:
; OPT: br BB11_1{{$}}
; OPT: BB11_7:
define i32 @doublediamond_in_a_loop(i32 %a, i32 %b, i32* %p) {
entry:
br label %header

View File

@ -50,22 +50,35 @@ define i32 @yes1(i32* %q) {
; rearranged to make the stack contiguous.
; CHECK-LABEL: stack_uses:
; CHECK-NEXT: .param i32{{$}}
; CHECK-NEXT: .param i32, i32, i32, i32{{$}}
; CHECK-NEXT: .result i32{{$}}
; CHECK-NEXT: local i32, i32{{$}}
; CHECK-NEXT: i32.const $1=, 1{{$}}
; CHECK-NEXT: i32.const $2=, 0{{$}}
; CHECK-NEXT: i32.and $push0=, $0, $1{{$}}
; CHECK-NEXT: i32.eq $push1=, $pop0, $2{{$}}
; CHECK-NEXT: block BB4_2{{$}}
; CHECK-NEXT: br_if $pop1, BB4_2{{$}}
; CHECK-NEXT: return $2{{$}}
; CHECK-NEXT: BB4_2:{{$}}
; CHECK-NEXT: return $1{{$}}
define i32 @stack_uses(i32 %x) {
; CHECK-NEXT: .local i32, i32{{$}}
; CHECK-NEXT: i32.const $4=, 1{{$}}
; CHECK-NEXT: i32.const $5=, 2{{$}}
; CHECK-NEXT: i32.lt_s $push0=, $0, $4{{$}}
; CHECK-NEXT: i32.lt_s $push1=, $1, $5{{$}}
; CHECK-NEXT: i32.xor $push4=, $pop0, $pop1{{$}}
; CHECK-NEXT: i32.lt_s $push2=, $2, $4{{$}}
; CHECK-NEXT: i32.lt_s $push3=, $3, $5{{$}}
; CHECK-NEXT: i32.xor $push5=, $pop2, $pop3{{$}}
; CHECK-NEXT: i32.xor $push6=, $pop4, $pop5{{$}}
; CHECK-NEXT: i32.ne $push7=, $pop6, $4{{$}}
; CHECK-NEXT: block BB4_2{{$}}
; CHECK-NEXT: br_if $pop7, BB4_2{{$}}
; CHECK-NEXT: i32.const $push8=, 0{{$}}
; CHECK-NEXT: return $pop8{{$}}
; CHECK-NEXT: BB4_2:
; CHECK-NEXT: return $4{{$}}
define i32 @stack_uses(i32 %x, i32 %y, i32 %z, i32 %w) {
entry:
%c = trunc i32 %x to i1
br i1 %c, label %true, label %false
%c = icmp sle i32 %x, 0
%d = icmp sle i32 %y, 1
%e = icmp sle i32 %z, 0
%f = icmp sle i32 %w, 1
%g = xor i1 %c, %d
%h = xor i1 %e, %f
%i = xor i1 %g, %h
br i1 %i, label %true, label %false
true:
ret i32 0
false:

View File

@ -1,6 +1,7 @@
; RUN: llc < %s -asm-verbose=false | FileCheck %s
; RUN: llc < %s -asm-verbose=false -disable-block-placement | FileCheck %s
; Test switch instructions.
; Test switch instructions. Block placement is disabled because it reorders
; the blocks in a way that isn't interesting here.
target datalayout = "e-p:32:32-i64:64-n32:64-S128"
target triple = "wasm32-unknown-unknown"