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ispc/ispc.cpp
Matt Pharr 73bf552cd6 Add support for coalescing memory accesses from gathers. 
There are two related optimizations that happen now.  (These
currently only apply for gathers where the mask is known to be
all on, and to gathers that are accessing 32-bit sized elements,
but both of these may be generalized in the future.)

First, for any single gather, we are now more flexible in mapping it
to individual memory operations.  Previously, we would only either map
it to a general gather (one scalar load per SIMD lane), or an 
unaligned vector load (if the program instances could be determined
to be accessing a sequential set of locations in memory.)

Now, we are able to break gathers into scalar, 2-wide (i.e. 64-bit),
4-wide, or 8-wide loads.  Further, we now generate code that shuffles
these loads around.  Doing fewer, larger loads in this manner, when
possible, can be more efficient.

Second, we can coalesce memory accesses across multiple gathers. If 
we have a series of gathers without any memory writes in the middle,
then we try to analyze their reads collectively and choose an efficient
set of loads for them.  Not only does this help if different gathers
reuse values from the same location in memory, but it's specifically
helpful when data with AOS layout is being accessed; in this case,
we're often able to generate wide vector loads and appropriate shuffles
automatically.
2012-02-10 13:10:39 -08:00

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/*
Copyright (c) 2010-2011, Intel Corporation
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:
* Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.
* Neither the name of Intel Corporation nor the names of its
contributors may be used to endorse or promote products derived from
this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/** @file ispc.cpp
@brief ispc global definitions
*/
#include "ispc.h"
#include "module.h"
#include "util.h"
#include "llvmutil.h"
#include <stdio.h>
#ifdef ISPC_IS_WINDOWS
#include <windows.h>
#include <direct.h>
#define strcasecmp stricmp
#endif
#include <llvm/LLVMContext.h>
#include <llvm/Module.h>
#include <llvm/Analysis/DIBuilder.h>
#include <llvm/Analysis/DebugInfo.h>
#include <llvm/Support/Dwarf.h>
#include <llvm/Instructions.h>
#include <llvm/Target/TargetMachine.h>
#include <llvm/Target/TargetOptions.h>
#include <llvm/Target/TargetData.h>
#if defined(LLVM_3_0) || defined(LLVM_3_0svn) || defined(LLVM_3_1svn)
#include <llvm/Support/TargetRegistry.h>
#include <llvm/Support/TargetSelect.h>
#else
#include <llvm/Target/TargetRegistry.h>
#include <llvm/Target/TargetSelect.h>
#include <llvm/Target/SubtargetFeature.h>
#endif
#include <llvm/Support/Host.h>
Globals *g;
Module *m;
///////////////////////////////////////////////////////////////////////////
// Target
bool
Target::GetTarget(const char *arch, const char *cpu, const char *isa,
bool pic, Target *t) {
if (cpu == NULL) {
std::string hostCPU = llvm::sys::getHostCPUName();
if (hostCPU.size() > 0)
cpu = strdup(hostCPU.c_str());
else {
fprintf(stderr, "Warning: unable to determine host CPU!\n");
cpu = "generic";
}
}
t->cpu = cpu;
if (isa == NULL) {
if (!strcasecmp(cpu, "atom"))
isa = "sse2";
#if defined(LLVM_3_0) || defined(LLVM_3_0svn) || defined(LLVM_3_1svn)
else if (!strcasecmp(cpu, "sandybridge") ||
!strcasecmp(cpu, "corei7-avx"))
isa = "avx";
#endif // LLVM_3_0
else
isa = "sse4";
}
if (arch == NULL)
arch = "x86-64";
bool error = false;
t->generatePIC = pic;
// Make sure the target architecture is a known one; print an error
// with the valid ones otherwise.
t->target = NULL;
for (llvm::TargetRegistry::iterator iter = llvm::TargetRegistry::begin();
iter != llvm::TargetRegistry::end(); ++iter) {
if (std::string(arch) == iter->getName()) {
t->target = &*iter;
break;
}
}
if (t->target == NULL) {
fprintf(stderr, "Invalid architecture \"%s\"\nOptions: ", arch);
llvm::TargetRegistry::iterator iter;
for (iter = llvm::TargetRegistry::begin();
iter != llvm::TargetRegistry::end(); ++iter)
fprintf(stderr, "%s ", iter->getName());
fprintf(stderr, "\n");
error = true;
}
else {
t->arch = arch;
}
if (!strcasecmp(isa, "sse2")) {
t->isa = Target::SSE2;
t->nativeVectorWidth = 4;
t->vectorWidth = 4;
t->attributes = "+sse,+sse2,-sse3,-sse41,-sse42,-sse4a,-ssse3,-popcnt";
t->maskingIsFree = false;
t->allOffMaskIsSafe = false;
t->maskBitCount = 32;
}
else if (!strcasecmp(isa, "sse2-x2")) {
t->isa = Target::SSE2;
t->nativeVectorWidth = 4;
t->vectorWidth = 8;
t->attributes = "+sse,+sse2,-sse3,-sse41,-sse42,-sse4a,-ssse3,-popcnt";
t->maskingIsFree = false;
t->allOffMaskIsSafe = false;
t->maskBitCount = 32;
}
else if (!strcasecmp(isa, "sse4")) {
t->isa = Target::SSE4;
t->nativeVectorWidth = 4;
t->vectorWidth = 4;
t->attributes = "+sse,+sse2,+sse3,+sse41,-sse42,-sse4a,+ssse3,-popcnt,+cmov";
t->maskingIsFree = false;
t->allOffMaskIsSafe = false;
t->maskBitCount = 32;
}
else if (!strcasecmp(isa, "sse4x2") || !strcasecmp(isa, "sse4-x2")) {
t->isa = Target::SSE4;
t->nativeVectorWidth = 4;
t->vectorWidth = 8;
t->attributes = "+sse,+sse2,+sse3,+sse41,-sse42,-sse4a,+ssse3,-popcnt,+cmov";
t->maskingIsFree = false;
t->allOffMaskIsSafe = false;
t->maskBitCount = 32;
}
else if (!strcasecmp(isa, "generic-4")) {
t->isa = Target::GENERIC;
t->nativeVectorWidth = 4;
t->vectorWidth = 4;
t->maskingIsFree = true;
t->allOffMaskIsSafe = true;
t->maskBitCount = 1;
}
else if (!strcasecmp(isa, "generic-8")) {
t->isa = Target::GENERIC;
t->nativeVectorWidth = 8;
t->vectorWidth = 8;
t->maskingIsFree = true;
t->allOffMaskIsSafe = true;
t->maskBitCount = 1;
}
else if (!strcasecmp(isa, "generic-16")) {
t->isa = Target::GENERIC;
t->nativeVectorWidth = 16;
t->vectorWidth = 16;
t->maskingIsFree = true;
t->allOffMaskIsSafe = true;
t->maskBitCount = 1;
}
else if (!strcasecmp(isa, "generic-1")) {
t->isa = Target::GENERIC;
t->nativeVectorWidth = 1;
t->vectorWidth = 1;
t->maskingIsFree = false;
t->allOffMaskIsSafe = false;
t->maskBitCount = 32;
}
#if defined(LLVM_3_0) || defined(LLVM_3_0svn) || defined(LLVM_3_1svn)
else if (!strcasecmp(isa, "avx")) {
t->isa = Target::AVX;
t->nativeVectorWidth = 8;
t->vectorWidth = 8;
t->attributes = "+avx,+popcnt,+cmov";
t->maskingIsFree = false;
t->allOffMaskIsSafe = false;
t->maskBitCount = 32;
}
else if (!strcasecmp(isa, "avx-x2")) {
t->isa = Target::AVX;
t->nativeVectorWidth = 8;
t->vectorWidth = 16;
t->attributes = "+avx,+popcnt,+cmov";
t->maskingIsFree = false;
t->allOffMaskIsSafe = false;
t->maskBitCount = 32;
}
#endif // LLVM 3.0+
#if defined(LLVM_3_1svn)
else if (!strcasecmp(isa, "avx2")) {
t->isa = Target::AVX2;
t->nativeVectorWidth = 8;
t->vectorWidth = 8;
t->attributes = "+avx2,+popcnt,+cmov,+f16c";
t->maskingIsFree = false;
t->allOffMaskIsSafe = false;
t->maskBitCount = 32;
}
else if (!strcasecmp(isa, "avx2-x2")) {
t->isa = Target::AVX2;
t->nativeVectorWidth = 16;
t->vectorWidth = 16;
t->attributes = "+avx2,+popcnt,+cmov,+f16c";
t->maskingIsFree = false;
t->allOffMaskIsSafe = false;
t->maskBitCount = 32;
}
#endif // LLVM 3.1
else {
fprintf(stderr, "Target ISA \"%s\" is unknown. Choices are: %s\n",
isa, SupportedTargetISAs());
error = true;
}
if (!error) {
llvm::TargetMachine *targetMachine = t->GetTargetMachine();
const llvm::TargetData *targetData = targetMachine->getTargetData();
t->is32Bit = (targetData->getPointerSize() == 4);
}
return !error;
}
const char *
Target::SupportedTargetCPUs() {
return "atom, barcelona, core2, corei7, "
#if defined(LLVM_3_0) || defined(LLVM_3_0svn) || defined(LLVM_3_1svn)
"corei7-avx, "
#endif
"istanbul, nocona, penryn, "
#ifdef LLVM_2_9
"sandybridge, "
#endif
"westmere";
}
const char *
Target::SupportedTargetArchs() {
return "x86, x86-64";
}
const char *
Target::SupportedTargetISAs() {
return "sse2, sse2-x2, sse4, sse4-x2"
#ifndef LLVM_2_9
", avx, avx-x2"
#endif // !LLVM_2_9
#ifdef LLVM_3_1svn
", avx2, avx2-x2"
#endif // LLVM_3_1svn
", generic-4, generic-8, generic-16, generic-1";
}
std::string
Target::GetTripleString() const {
llvm::Triple triple;
// Start with the host triple as the default
#if defined(LLVM_3_1) || defined(LLVM_3_1svn)
triple.setTriple(llvm::sys::getDefaultTargetTriple());
#else
triple.setTriple(llvm::sys::getHostTriple());
#endif
// And override the arch in the host triple based on what the user
// specified. Here we need to deal with the fact that LLVM uses one
// naming convention for targets TargetRegistry, but wants some
// slightly different ones for the triple. TODO: is there a way to
// have it do this remapping, which would presumably be a bit less
// error prone?
if (arch == "x86")
triple.setArchName("i386");
else if (arch == "x86-64")
triple.setArchName("x86_64");
else
triple.setArchName(arch);
return triple.str();
}
llvm::TargetMachine *
Target::GetTargetMachine() const {
std::string triple = GetTripleString();
llvm::Reloc::Model relocModel = generatePIC ? llvm::Reloc::PIC_ :
llvm::Reloc::Default;
#if defined(LLVM_3_1svn)
std::string featuresString = attributes;
llvm::TargetOptions options;
if (g->opt.fastMath == true)
options.UnsafeFPMath = 1;
llvm::TargetMachine *targetMachine =
target->createTargetMachine(triple, cpu, featuresString, options,
relocModel);
#elif defined(LLVM_3_0)
std::string featuresString = attributes;
llvm::TargetMachine *targetMachine =
target->createTargetMachine(triple, cpu, featuresString, relocModel);
#else // LLVM 2.9
#ifdef ISPC_IS_APPLE
relocModel = llvm::Reloc::PIC_;
#endif // ISPC_IS_APPLE
std::string featuresString = cpu + std::string(",") + attributes;
llvm::TargetMachine *targetMachine =
target->createTargetMachine(triple, featuresString);
#ifndef ISPC_IS_WINDOWS
targetMachine->setRelocationModel(relocModel);
#endif // !ISPC_IS_WINDOWS
#endif // LLVM_2_9
Assert(targetMachine != NULL);
targetMachine->setAsmVerbosityDefault(true);
return targetMachine;
}
const char *
Target::GetISAString() const {
switch (isa) {
case Target::SSE2:
return "sse2";
case Target::SSE4:
return "sse4";
case Target::AVX:
return "avx";
case Target::AVX2:
return "avx2";
case Target::GENERIC:
return "generic";
default:
FATAL("Unhandled target in GetISAString()");
}
return "";
}
static bool
lGenericTypeLayoutIndeterminate(LLVM_TYPE_CONST llvm::Type *type) {
if (type->isPrimitiveType() || type->isIntegerTy())
return false;
if (type == LLVMTypes::BoolVectorType ||
type == LLVMTypes::MaskType ||
type == LLVMTypes::Int1VectorType)
return true;
LLVM_TYPE_CONST llvm::ArrayType *at =
llvm::dyn_cast<LLVM_TYPE_CONST llvm::ArrayType>(type);
if (at != NULL)
return lGenericTypeLayoutIndeterminate(at->getElementType());
LLVM_TYPE_CONST llvm::PointerType *pt =
llvm::dyn_cast<LLVM_TYPE_CONST llvm::PointerType>(type);
if (pt != NULL)
return false;
LLVM_TYPE_CONST llvm::StructType *st =
llvm::dyn_cast<LLVM_TYPE_CONST llvm::StructType>(type);
if (st != NULL) {
for (int i = 0; i < (int)st->getNumElements(); ++i)
if (lGenericTypeLayoutIndeterminate(st->getElementType(i)))
return true;
return false;
}
Assert(llvm::isa<LLVM_TYPE_CONST llvm::VectorType>(type));
return true;
}
llvm::Value *
Target::SizeOf(LLVM_TYPE_CONST llvm::Type *type,
llvm::BasicBlock *insertAtEnd) {
if (isa == Target::GENERIC &&
lGenericTypeLayoutIndeterminate(type)) {
llvm::Value *index[1] = { LLVMInt32(1) };
LLVM_TYPE_CONST llvm::PointerType *ptrType = llvm::PointerType::get(type, 0);
llvm::Value *voidPtr = llvm::ConstantPointerNull::get(ptrType);
#if defined(LLVM_3_0) || defined(LLVM_3_0svn) || defined(LLVM_3_1svn)
llvm::ArrayRef<llvm::Value *> arrayRef(&index[0], &index[1]);
llvm::Instruction *gep =
llvm::GetElementPtrInst::Create(voidPtr, arrayRef, "sizeof_gep",
insertAtEnd);
#else
llvm::Instruction *gep =
llvm::GetElementPtrInst::Create(voidPtr, &index[0], &index[1],
"sizeof_gep", insertAtEnd);
#endif
if (is32Bit || g->opt.force32BitAddressing)
return new llvm::PtrToIntInst(gep, LLVMTypes::Int32Type,
"sizeof_int", insertAtEnd);
else
return new llvm::PtrToIntInst(gep, LLVMTypes::Int64Type,
"sizeof_int", insertAtEnd);
}
const llvm::TargetData *td = GetTargetMachine()->getTargetData();
Assert(td != NULL);
uint64_t byteSize = td->getTypeSizeInBits(type) / 8;
if (is32Bit || g->opt.force32BitAddressing)
return LLVMInt32((int32_t)byteSize);
else
return LLVMInt64(byteSize);
}
llvm::Value *
Target::StructOffset(LLVM_TYPE_CONST llvm::Type *type, int element,
llvm::BasicBlock *insertAtEnd) {
if (isa == Target::GENERIC &&
lGenericTypeLayoutIndeterminate(type) == true) {
llvm::Value *indices[2] = { LLVMInt32(0), LLVMInt32(element) };
LLVM_TYPE_CONST llvm::PointerType *ptrType = llvm::PointerType::get(type, 0);
llvm::Value *voidPtr = llvm::ConstantPointerNull::get(ptrType);
#if defined(LLVM_3_0) || defined(LLVM_3_0svn) || defined(LLVM_3_1svn)
llvm::ArrayRef<llvm::Value *> arrayRef(&indices[0], &indices[2]);
llvm::Instruction *gep =
llvm::GetElementPtrInst::Create(voidPtr, arrayRef, "offset_gep",
insertAtEnd);
#else
llvm::Instruction *gep =
llvm::GetElementPtrInst::Create(voidPtr, &indices[0], &indices[2],
"offset_gep", insertAtEnd);
#endif
if (is32Bit || g->opt.force32BitAddressing)
return new llvm::PtrToIntInst(gep, LLVMTypes::Int32Type,
"offset_int", insertAtEnd);
else
return new llvm::PtrToIntInst(gep, LLVMTypes::Int64Type,
"offset_int", insertAtEnd);
}
const llvm::TargetData *td = GetTargetMachine()->getTargetData();
Assert(td != NULL);
LLVM_TYPE_CONST llvm::StructType *structType =
llvm::dyn_cast<LLVM_TYPE_CONST llvm::StructType>(type);
Assert(structType != NULL);
const llvm::StructLayout *sl = td->getStructLayout(structType);
Assert(sl != NULL);
uint64_t offset = sl->getElementOffset(element);
if (is32Bit || g->opt.force32BitAddressing)
return LLVMInt32((int32_t)offset);
else
return LLVMInt64(offset);
}
///////////////////////////////////////////////////////////////////////////
// Opt
Opt::Opt() {
level = 1;
fastMath = false;
fastMaskedVload = false;
force32BitAddressing = true;
unrollLoops = true;
disableAsserts = false;
disableMaskAllOnOptimizations = false;
disableHandlePseudoMemoryOps = false;
disableBlendedMaskedStores = false;
disableCoherentControlFlow = false;
disableUniformControlFlow = false;
disableGatherScatterOptimizations = false;
disableMaskedStoreToStore = false;
disableGatherScatterFlattening = false;
disableUniformMemoryOptimizations = false;
disableCoalescing = false;
}
///////////////////////////////////////////////////////////////////////////
// Globals
Globals::Globals() {
mathLib = Globals::Math_ISPC;
includeStdlib = true;
runCPP = true;
debugPrint = false;
disableWarnings = false;
warningsAsErrors = false;
quiet = false;
disableLineWrap = false;
emitPerfWarnings = true;
emitInstrumentation = false;
generateDebuggingSymbols = false;
enableFuzzTest = false;
fuzzTestSeed = -1;
mangleFunctionsWithTarget = false;
ctx = new llvm::LLVMContext;
#ifdef ISPC_IS_WINDOWS
_getcwd(currentDirectory, sizeof(currentDirectory));
#else
if (getcwd(currentDirectory, sizeof(currentDirectory)) == NULL)
FATAL("Current directory path too long!");
#endif
}
///////////////////////////////////////////////////////////////////////////
// SourcePos
SourcePos::SourcePos(const char *n, int fl, int fc, int ll, int lc) {
name = n;
if (name == NULL) {
if (m != NULL)
name = m->module->getModuleIdentifier().c_str();
else
name = "(unknown)";
}
first_line = fl;
first_column = fc;
last_line = ll != 0 ? ll : fl;
last_column = lc != 0 ? lc : fc;
}
llvm::DIFile
SourcePos::GetDIFile() const {
std::string directory, filename;
GetDirectoryAndFileName(g->currentDirectory, name, &directory, &filename);
return m->diBuilder->createFile(filename, directory);
}
void
SourcePos::Print() const {
printf(" @ [%s:%d.%d - %d.%d] ", name, first_line, first_column,
last_line, last_column);
}
bool
SourcePos::operator==(const SourcePos &p2) const {
return (!strcmp(name, p2.name) &&
first_line == p2.first_line &&
first_column == p2.first_column &&
last_line == p2.last_line &&
last_column == p2.last_column);
}
SourcePos
Union(const SourcePos &p1, const SourcePos &p2) {
if (strcmp(p1.name, p2.name) != 0)
return p1;
SourcePos ret;
ret.name = p1.name;
ret.first_line = std::min(p1.first_line, p2.first_line);
ret.first_column = std::min(p1.first_column, p2.first_column);
ret.last_line = std::max(p1.last_line, p2.last_line);
ret.last_column = std::max(p1.last_column, p2.last_column);
return ret;
}
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