[polly] r250019 - ScopInfo: Allow simple 'AddRec * Parameter' products in delinearization

[Tobias Grosser via llvm-commits]

Author: grosser
Date: Mon Oct 12 03:02:30 2015
New Revision: 250019

URL: http://llvm.org/viewvc/llvm-project?rev=250019&view=rev
Log:
ScopInfo: Allow simple 'AddRec * Parameter' products in delinearization

We also allow such products for cases where 'Parameter' is loaded within the
scop, but where we can dynamically verify that the value of 'Parameter' remains
unchanged during the execution of the scop.

This change relies on Polly's new RequiredILS tracking infrastructure recently
contributed by Johannes.

Added:
    polly/trunk/test/ScopInfo/multidim_parameter_addrec_product.ll
Modified:
    polly/trunk/lib/Analysis/ScopDetection.cpp

Modified: polly/trunk/lib/Analysis/ScopDetection.cpp
URL: http://llvm.org/viewvc/llvm-project/polly/trunk/lib/Analysis/ScopDetection.cpp?rev=250019&r1=250018&r2=250019&view=diff
==============================================================================
--- polly/trunk/lib/Analysis/ScopDetection.cpp (original)
+++ polly/trunk/lib/Analysis/ScopDetection.cpp Mon Oct 12 03:02:30 2015
@@ -495,9 +495,6 @@ bool ScopDetection::hasAffineMemoryAcces
     // First step: collect parametric terms in all array references.
     SmallVector<const SCEV *, 4> Terms;
     for (const auto &Pair : Context.Accesses[BasePointer]) {
-      if (auto *AF = dyn_cast<SCEVAddRecExpr>(Pair.second))
-        SE->collectParametricTerms(AF, Terms);
-
       // In case the outermost expression is a plain add, we check if any of its
       // terms has the form 4 * %inst * %param * %param ..., aka a term that
       // contains a product between a parameter and an instruction that is
@@ -530,6 +527,8 @@ bool ScopDetection::hasAffineMemoryAcces
           }
         }
       }
+      if (Terms.empty())
+        SE->collectParametricTerms(Pair.second, Terms);
     }
 
     // Second step: find array shape.
@@ -539,13 +538,19 @@ bool ScopDetection::hasAffineMemoryAcces
     if (!AllowNonAffine)
       for (const SCEV *DelinearizedSize : Shape->DelinearizedSizes) {
         if (auto *Unknown = dyn_cast<SCEVUnknown>(DelinearizedSize)) {
-          auto *value = dyn_cast<Value>(Unknown->getValue());
-          if (isa<UndefValue>(value)) {
+          auto *V = dyn_cast<Value>(Unknown->getValue());
+          if (isa<UndefValue>(V)) {
             invalid<ReportDifferentArrayElementSize>(
                 Context, /*Assert=*/true,
                 Context.Accesses[BasePointer].front().first, BaseValue);
             return false;
           }
+          if (auto *Load = dyn_cast<LoadInst>(V)) {
+            if (Context.CurRegion.contains(Load) &&
+                isHoistableLoad(Load, CurRegion, *LI, *SE))
+              Context.RequiredILS.insert(Load);
+            continue;
+          }
         }
         if (hasScalarDepsInsideRegion(DelinearizedSize, &CurRegion))
           invalid<ReportNonAffineAccess>(

Added: polly/trunk/test/ScopInfo/multidim_parameter_addrec_product.ll
URL: http://llvm.org/viewvc/llvm-project/polly/trunk/test/ScopInfo/multidim_parameter_addrec_product.ll?rev=250019&view=auto
==============================================================================
--- polly/trunk/test/ScopInfo/multidim_parameter_addrec_product.ll (added)
+++ polly/trunk/test/ScopInfo/multidim_parameter_addrec_product.ll Mon Oct 12 03:02:30 2015
@@ -0,0 +1,64 @@
+; RUN: opt %loadPolly -polly-scops -analyze < %s | FileCheck %s
+;
+;    void foo(float *A, long *p) {
+;      for (long i = 0; i < 100; i++)
+;        for (long j = 0; j < 100; j++)
+;          A[i * (*p) + j] += i + j;
+;    }
+
+; CHECK:  Invariant Accesses: {
+; CHECK-NEXT:          ReadAccess :=       [Reduction Type: NONE] [Scalar: 0]
+; CHECK-NEXT:              [p] -> { Stmt_bb5[i0, i1] -> MemRef_p[0] };
+; CHECK-NEXT:          Execution Context: [p] -> {  :  }
+; CHECK-NEXT:  }
+
+; CHECK: ReadAccess :=       [Reduction Type: NONE] [Scalar: 0]
+; CHECK:     [p] -> { Stmt_bb5[i0, i1] -> MemRef_A[i0, i1] };
+; CHECK: MustWriteAccess :=  [Reduction Type: NONE] [Scalar: 0]
+; CHECK:     [p] -> { Stmt_bb5[i0, i1] -> MemRef_A[i0, i1] };
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+
+define void @foo(float* %A, i64* %p) {
+bb:
+  br label %bb2
+
+bb2:                                              ; preds = %bb16, %bb
+  %i.0 = phi i64 [ 0, %bb ], [ %tmp17, %bb16 ]
+  %exitcond1 = icmp ne i64 %i.0, 100
+  br i1 %exitcond1, label %bb3, label %bb18
+
+bb3:                                              ; preds = %bb2
+  br label %bb4
+
+bb4:                                              ; preds = %bb13, %bb3
+  %j.0 = phi i64 [ 0, %bb3 ], [ %tmp14, %bb13 ]
+  %exitcond = icmp ne i64 %j.0, 100
+  br i1 %exitcond, label %bb5, label %bb15
+
+bb5:                                              ; preds = %bb4
+  %tmp = add nuw nsw i64 %i.0, %j.0
+  %tmp6 = sitofp i64 %tmp to float
+  %pval = load i64, i64* %p, align 8
+  %tmp8 = mul nsw i64 %i.0, %pval
+  %tmp9 = add nsw i64 %tmp8, %j.0
+  %tmp10 = getelementptr inbounds float, float* %A, i64 %tmp9
+  %tmp11 = load float, float* %tmp10, align 4
+  %tmp12 = fadd float %tmp11, %tmp6
+  store float %tmp12, float* %tmp10, align 4
+  br label %bb13
+
+bb13:                                             ; preds = %bb5
+  %tmp14 = add nuw nsw i64 %j.0, 1
+  br label %bb4
+
+bb15:                                             ; preds = %bb4
+  br label %bb16
+
+bb16:                                             ; preds = %bb15
+  %tmp17 = add nuw nsw i64 %i.0, 1
+  br label %bb2
+
+bb18:                                             ; preds = %bb2
+  ret void
+}