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Allow multidimensional accesses in the IslExprBuilder. 

This resolved the issues with delinearized accesses that might alias,
  thus delinearization doesn't deactivate runtime alias checks anymore.

Differential Revision: http://reviews.llvm.org/D5614

llvm-svn: 219078
This commit is contained in:
Johannes Doerfert 2014-10-05 11:33:59 +00:00
parent 1a28a8938e
commit 2ef33e9f16
5 changed files with 123 additions and 19 deletions
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14
polly/include/polly/CodeGen/IslExprBuilder.h
View File

@ -18,6 +18,10 @@
#include <map>
namespace llvm {
class SCEVExpander;
}
namespace polly {
/// @brief LLVM-IR generator for isl_ast_expr[essions]
@ -89,8 +93,11 @@ public:
/// variables (identified by an isl_id). The IDTOValue map
/// specifies the LLVM-IR Values that correspond to these
/// parameters and variables.
IslExprBuilder(PollyIRBuilder &Builder, IDToValueTy &IDToValue)
: Builder(Builder), IDToValue(IDToValue) {}
/// @param Expander A SCEVExpander to create the indices for multi
/// dimensional accesses.
IslExprBuilder(PollyIRBuilder &Builder, IDToValueTy &IDToValue,
llvm::SCEVExpander &Expander)
: Builder(Builder), IDToValue(IDToValue), Expander(Expander) {}
/// @brief Create LLVM-IR for an isl_ast_expr[ession].
///
@ -120,6 +127,9 @@ private:
PollyIRBuilder &Builder;
std::map<isl_id *, llvm::Value *> &IDToValue;
/// @brief A SCEVExpander to translate dimension sizes to llvm values.
llvm::SCEVExpander &Expander;
llvm::Value *createOp(__isl_take isl_ast_expr *Expr);
llvm::Value *createOpUnary(__isl_take isl_ast_expr *Expr);
llvm::Value *createOpAccess(__isl_take isl_ast_expr *Expr);

6
polly/lib/Analysis/ScopDetection.cpp
View File

@ -202,12 +202,6 @@ ScopDetection::ScopDetection() : FunctionPass(ID) {
return;
}
if (PollyDelinearize) {
DEBUG(errs() << "WARNING: We disable runtime alias checks as "
"delinearization is enabled.\n");
PollyUseRuntimeAliasChecks = false;
}
if (AllowNonAffine) {
DEBUG(errs() << "WARNING: We disable runtime alias checks as non affine "
"accesses are enabled.\n");

15
polly/lib/CodeGen/IslCodeGeneration.cpp
View File

@ -57,8 +57,12 @@ class IslNodeBuilder {
public:
IslNodeBuilder(PollyIRBuilder &Builder, ScopAnnotator &Annotator, Pass *P,
LoopInfo &LI, ScalarEvolution &SE, DominatorTree &DT)
: Builder(Builder), Annotator(Annotator), ExprBuilder(Builder, IDToValue),
P(P), LI(LI), SE(SE), DT(DT) {}
: Builder(Builder), Annotator(Annotator),
Rewriter(new SCEVExpander(SE, "polly")),
ExprBuilder(Builder, IDToValue, *Rewriter), P(P), LI(LI), SE(SE),
DT(DT) {}
~IslNodeBuilder() { delete Rewriter; }
/// @brief Add the mappings from array id's to array llvm::Value's.
void addMemoryAccesses(Scop &S);
@ -69,6 +73,10 @@ public:
private:
PollyIRBuilder &Builder;
ScopAnnotator &Annotator;
/// @brief A SCEVExpander to create llvm values from SCEVs.
SCEVExpander *Rewriter;
IslExprBuilder ExprBuilder;
Pass *P;
LoopInfo &LI;
@ -532,7 +540,6 @@ void IslNodeBuilder::create(__isl_take isl_ast_node *Node) {
}
void IslNodeBuilder::addParameters(__isl_take isl_set *Context) {
SCEVExpander Rewriter(SE, "polly");
for (unsigned i = 0; i < isl_set_dim(Context, isl_dim_param); ++i) {
isl_id *Id;
@ -544,7 +551,7 @@ void IslNodeBuilder::addParameters(__isl_take isl_set *Context) {
Scev = (const SCEV *)isl_id_get_user(Id);
T = dyn_cast<IntegerType>(Scev->getType());
InsertLocation = --(Builder.GetInsertBlock()->end());
Value *V = Rewriter.expandCodeFor(Scev, T, InsertLocation);
Value *V = Rewriter->expandCodeFor(Scev, T, InsertLocation);
IDToValue[Id] = V;
isl_id_free(Id);

29
polly/lib/CodeGen/IslExprBuilder.cpp
View File

@ -14,6 +14,7 @@
#include "polly/ScopInfo.h"
#include "polly/Support/GICHelper.h"
#include "llvm/Analysis/ScalarEvolutionExpander.h"
#include "llvm/Support/Debug.h"
using namespace llvm;
@ -100,10 +101,6 @@ Value *IslExprBuilder::createAccessAddress(isl_ast_expr *Expr) {
assert(isl_ast_expr_get_op_n_arg(Expr) >= 2 &&
"We need at least two operands to create a member access.");
// TODO: Support for multi-dimensional array.
assert(isl_ast_expr_get_op_n_arg(Expr) == 2 &&
"Multidimensional access functions are not supported yet");
Value *Base, *IndexOp, *Access;
isl_ast_expr *BaseExpr;
isl_id *BaseId;
@ -121,9 +118,27 @@ Value *IslExprBuilder::createAccessAddress(isl_ast_expr *Expr) {
Base = Builder.CreateBitCast(Base, SAI->getType(),
"polly.access.cast." + BaseName);
IndexOp = create(isl_ast_expr_get_op_arg(Expr, 1));
assert(IndexOp->getType()->isIntegerTy() &&
"Access index should be an integer");
IndexOp = nullptr;
for (unsigned u = 1, e = isl_ast_expr_get_op_n_arg(Expr); u < e; u++) {
Value *NextIndex = create(isl_ast_expr_get_op_arg(Expr, u));
assert(NextIndex->getType()->isIntegerTy() &&
"Access index should be an integer");
if (!IndexOp)
IndexOp = NextIndex;
else
IndexOp = Builder.CreateAdd(IndexOp, NextIndex);
// For every but the last dimension multiply the size, for the last
// dimension we can exit the loop.
if (u + 1 >= e)
break;
const SCEV *DimSCEV = SAI->getDimensionSize(u - 1);
Value *DimSize = Expander.expandCodeFor(DimSCEV, IndexOp->getType(),
Builder.GetInsertPoint());
IndexOp = Builder.CreateMul(IndexOp, DimSize);
}
Access = Builder.CreateGEP(Base, IndexOp, "polly.access." + BaseName);

78
polly/test/Isl/CodeGen/aliasing_multidimensional_access.ll Normal file
View File

@ -0,0 +1,78 @@
; RUN: opt %loadPolly -S -polly-codegen-isl -polly-code-generator=isl -polly-delinearize < %s | FileCheck %s
;
; Check that we calculate the maximal access into array A correctly.
;
; CHECK: %[[TMP0:[._0-9a-zA-Z]*]] = mul i64 99, %m
; CHECK: %[[TMP1:[._0-9a-zA-Z]*]] = add i64 %[[TMP0]], 149
; CHECK: %[[TMP2:[._0-9a-zA-Z]*]] = mul i64 %[[TMP1]], %p
; CHECK: %[[TMP3:[._0-9a-zA-Z]*]] = add i64 %[[TMP2]], 150
; CHECK: %polly.access.A{{[0-9]*}} = getelementptr double* %A, i64 %[[TMP3]]
;
; void foo(long n, long m, long p, double A[n][m][p], int *B) {
; for (long i = 0; i < 100; i++)
; for (long j = 0; j < 150; j++)
; for (long k = 0; k < 150; k++)
; A[i][j][k] = B[k];
; }
;
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
define void @foo(i64 %n, i64 %m, i64 %p, double* %A, i32* %B) {
entry:
br label %for.cond
for.cond: ; preds = %for.inc13, %entry
%i.0 = phi i64 [ 0, %entry ], [ %inc14, %for.inc13 ]
%exitcond2 = icmp ne i64 %i.0, 100
br i1 %exitcond2, label %for.body, label %for.end15
for.body: ; preds = %for.cond
br label %for.cond1
for.cond1: ; preds = %for.inc10, %for.body
%j.0 = phi i64 [ 0, %for.body ], [ %inc11, %for.inc10 ]
%exitcond1 = icmp ne i64 %j.0, 150
br i1 %exitcond1, label %for.body3, label %for.end12
for.body3: ; preds = %for.cond1
br label %for.cond4
for.cond4: ; preds = %for.inc, %for.body3
%k.0 = phi i64 [ 0, %for.body3 ], [ %inc, %for.inc ]
%exitcond = icmp ne i64 %k.0, 150
br i1 %exitcond, label %for.body6, label %for.end
for.body6: ; preds = %for.cond4
%arrayidx = getelementptr inbounds i32* %B, i64 %k.0
%tmp3 = load i32* %arrayidx, align 2
%conv = sitofp i32 %tmp3 to double
%tmp4 = mul nuw i64 %m, %p
%tmp5 = mul nsw i64 %i.0, %tmp4
%tmp6 = mul nsw i64 %j.0, %p
%arrayidx7.sum = add i64 %tmp5, %tmp6
%arrayidx8.sum = add i64 %arrayidx7.sum, %k.0
%arrayidx9 = getelementptr inbounds double* %A, i64 %arrayidx8.sum
store double %conv, double* %arrayidx9, align 8
br label %for.inc
for.inc: ; preds = %for.body6
%inc = add nsw i64 %k.0, 1
br label %for.cond4
for.end: ; preds = %for.cond4
br label %for.inc10
for.inc10: ; preds = %for.end
%inc11 = add nsw i64 %j.0, 1
br label %for.cond1
for.end12: ; preds = %for.cond1
br label %for.inc13
for.inc13: ; preds = %for.end12
%inc14 = add nsw i64 %i.0, 1
br label %for.cond
for.end15: ; preds = %for.cond
ret void
}