[PATCH] D26185: [ARM] Loop Strength Reduction crashes when targeting ARM or Thumb.

[Phabricator via llvm-commits]

This revision was automatically updated to reflect the committed changes.
Closed by commit rL286347: [ARM] Loop Strength Reduction crashes when targeting ARM or Thumb. (authored by alelab01).

Changed prior to commit:
  https://reviews.llvm.org/D26185?vs=76829&id=77314#toc

Repository:
  rL LLVM

https://reviews.llvm.org/D26185

Files:
  llvm/trunk/lib/Transforms/Scalar/LoopStrengthReduce.cpp
  llvm/trunk/test/Transforms/LoopStrengthReduce/ARM/addrec-is-loop-invariant.ll


Index: llvm/trunk/test/Transforms/LoopStrengthReduce/ARM/addrec-is-loop-invariant.ll
===================================================================
--- llvm/trunk/test/Transforms/LoopStrengthReduce/ARM/addrec-is-loop-invariant.ll
+++ llvm/trunk/test/Transforms/LoopStrengthReduce/ARM/addrec-is-loop-invariant.ll
@@ -0,0 +1,35 @@
+; RUN: llc -mtriple=armv8-eabi -verify-machineinstrs %s -o /dev/null
+
+; This test ensures that Loop Strength Reduction will
+; not create an Add Reccurence Expression if not all
+; its operands are loop invariants.
+
+define void @add_rec_expr() {
+entry:
+  br label %loop0
+
+loop0:
+  %c.0 = phi i32 [ 0, %entry ], [ %inc.0, %loop0 ]
+  %inc.0 = add nuw i32 %c.0, 1
+  br i1 undef, label %loop0, label %bb1
+
+bb1:
+  %mul.0 = mul i32 %c.0, %c.0
+  %gelptr.0 = getelementptr inbounds i16, i16* undef, i32 %mul.0
+  br label %loop1
+
+loop1:
+  %inc.1 = phi i32 [ %inc.2, %bb4 ], [ 0, %bb1 ]
+  %mul.1 = mul i32 %inc.1, %c.0
+  br label %bb3
+
+bb3:
+  %add.0 = add i32 undef, %mul.1
+  %gelptr.1 = getelementptr inbounds i16, i16* %gelptr.0, i32 %add.0
+  store i16 undef, i16* %gelptr.1, align 2
+  br label %bb4
+
+bb4:
+  %inc.2 = add nuw i32 %inc.1, 1
+  br label %loop1
+}
Index: llvm/trunk/lib/Transforms/Scalar/LoopStrengthReduce.cpp
===================================================================
--- llvm/trunk/lib/Transforms/Scalar/LoopStrengthReduce.cpp
+++ llvm/trunk/lib/Transforms/Scalar/LoopStrengthReduce.cpp
@@ -325,7 +325,7 @@
 
   // Look at addrec operands.
   if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(S))
-    if (!AR->getStart()->isZero()) {
+    if (!AR->getStart()->isZero() && AR->isAffine()) {
       DoInitialMatch(AR->getStart(), L, Good, Bad, SE);
       DoInitialMatch(SE.getAddRecExpr(SE.getConstant(AR->getType(), 0),
                                       AR->getStepRecurrence(SE),
@@ -568,7 +568,7 @@
 
   // Distribute the sdiv over addrec operands, if the addrec doesn't overflow.
   if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(LHS)) {
-    if (IgnoreSignificantBits || isAddRecSExtable(AR, SE)) {
+    if ((IgnoreSignificantBits || isAddRecSExtable(AR, SE)) && AR->isAffine()) {
       const SCEV *Step = getExactSDiv(AR->getStepRecurrence(SE), RHS, SE,
                                       IgnoreSignificantBits);
       if (!Step) return nullptr;
@@ -3196,7 +3196,7 @@
     return nullptr;
   } else if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(S)) {
     // Split a non-zero base out of an addrec.
-    if (AR->getStart()->isZero())
+    if (AR->getStart()->isZero() || !AR->isAffine())
       return S;
 
     const SCEV *Remainder = CollectSubexprs(AR->getStart(),


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D26185.77314.patch
Type: text/x-patch
Size: 2692 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20161109/a12b99aa/attachment.bin>