[polly] r279087 - [SCEVValidator] Don't reorder multiplies in extractConstantFactor.

[Eli Friedman via llvm-commits]

Author: efriedma
Date: Thu Aug 18 11:30:42 2016
New Revision: 279087

URL: http://llvm.org/viewvc/llvm-project?rev=279087&view=rev
Log:
[SCEVValidator] Don't reorder multiplies in extractConstantFactor.

The existing code would add the operands in the wrong order, and eventually
crash because the SCEV expression doesn't exactly match the parameter SCEV
expression in SCEVAffinator::visit. (SCEV doesn't sort the operands to
getMulExpr in general.)

Differential Revision: https://reviews.llvm.org/D23592


Added:
    polly/trunk/test/ScopInfo/scop-affine-parameter-ordering.ll
Modified:
    polly/trunk/lib/Support/SCEVValidator.cpp

Modified: polly/trunk/lib/Support/SCEVValidator.cpp
URL: http://llvm.org/viewvc/llvm-project/polly/trunk/lib/Support/SCEVValidator.cpp?rev=279087&r1=279086&r2=279087&view=diff
==============================================================================
--- polly/trunk/lib/Support/SCEVValidator.cpp (original)
+++ polly/trunk/lib/Support/SCEVValidator.cpp Thu Aug 18 11:30:42 2016
@@ -577,12 +577,10 @@ ParameterSetTy getParamsInAffineExpr(con
 
 std::pair<const SCEVConstant *, const SCEV *>
 extractConstantFactor(const SCEV *S, ScalarEvolution &SE) {
-
-  auto *LeftOver = SE.getConstant(S->getType(), 1);
   auto *ConstPart = cast<SCEVConstant>(SE.getConstant(S->getType(), 1));
 
   if (auto *Constant = dyn_cast<SCEVConstant>(S))
-    return std::make_pair(Constant, LeftOver);
+    return std::make_pair(Constant, SE.getConstant(S->getType(), 1));
 
   auto *AddRec = dyn_cast<SCEVAddRecExpr>(S);
   if (AddRec) {
@@ -627,12 +625,13 @@ extractConstantFactor(const SCEV *S, Sca
   if (!Mul)
     return std::make_pair(ConstPart, S);
 
+  SmallVector<const SCEV *, 4> LeftOvers;
   for (auto *Op : Mul->operands())
     if (isa<SCEVConstant>(Op))
       ConstPart = cast<SCEVConstant>(SE.getMulExpr(ConstPart, Op));
     else
-      LeftOver = SE.getMulExpr(LeftOver, Op);
+      LeftOvers.push_back(Op);
 
-  return std::make_pair(ConstPart, LeftOver);
+  return std::make_pair(ConstPart, SE.getMulExpr(LeftOvers));
 }
 } // namespace polly

Added: polly/trunk/test/ScopInfo/scop-affine-parameter-ordering.ll
URL: http://llvm.org/viewvc/llvm-project/polly/trunk/test/ScopInfo/scop-affine-parameter-ordering.ll?rev=279087&view=auto
==============================================================================
--- polly/trunk/test/ScopInfo/scop-affine-parameter-ordering.ll (added)
+++ polly/trunk/test/ScopInfo/scop-affine-parameter-ordering.ll Thu Aug 18 11:30:42 2016
@@ -0,0 +1,39 @@
+; RUN: opt -polly-process-unprofitable -polly-scops %s -analyze | FileCheck %s
+target datalayout = "e-m:e-i64:64-i128:128-n8:16:32:64-S128"
+target triple = "aarch64--linux-android"
+
+; Check for SCOP:
+; CHECK: Stmt_for_body8_us_us95_i
+; CHECK-NEXT: Domain :=
+; CHECK-NEXT: [p_0] -> { Stmt_for_body8_us_us95_i[i0] : 0 <= i0 <= 4 };
+; CHECK-NEXT: Schedule :=
+; CHECK-NEXT: [p_0] -> { Stmt_for_body8_us_us95_i[i0] -> [i0] };
+; CHECK-NEXT; MustWriteAccess := [Reduction Type: NONE] [Scalar: 0]
+; CHECK-NEXT; [p_0] -> { Stmt_for_body8_us_us95_i[i0] -> MemRef_0[1 + p_0] };
+; CHECK-NEXT }
+
+define void @test1() unnamed_addr align 2 {
+entry:
+  %xFactor.0.reload = load i32, i32* undef
+  %0 = load i8*, i8** undef, align 8
+  %div = udiv i32 0, %xFactor.0.reload
+  %1 = load i32, i32* undef, align 4
+  %mul = mul i32 %1, %xFactor.0.reload
+  %col.023.us.us85.i = add i32 %div, -1
+  %mul11.us.us93.i = mul i32 %col.023.us.us85.i, %mul
+  br label %for.body8.us.us95.i
+
+for.body8.us.us95.i:
+  %niter.i = phi i32 [ %niter.i.next, %for.body8.us.us95.i ], [ 0, %entry ]
+  %add12.us.us100.1.i = add i32 1, %mul11.us.us93.i
+  %idxprom13.us.us101.1.i = zext i32 %add12.us.us100.1.i to i64
+  %arrayidx14.us.us102.1.i = getelementptr inbounds i8, i8* %0, i64 %idxprom13.us.us101.1.i
+  store i8 0, i8* %arrayidx14.us.us102.1.i, align 1
+  %niter.ncmp.3.i = icmp eq i32 %niter.i, 4
+  %niter.i.next = add i32 %niter.i, 1
+  br i1 %niter.ncmp.3.i, label %for.body8.us.us95.epil.i.preheader, label %for.body8.us.us95.i
+
+for.body8.us.us95.epil.i.preheader:
+  ret void
+}
+