[PATCH] D87608: [ARM][MVE] Tail-predication: use unsigned SCEV ranges for tripcount

[Sjoerd Meijer via Phabricator via llvm-commits]

This revision was automatically updated to reflect the committed changes.
Closed by commit rG635b87511ec3: [ARM][MVE] Tail-predication: use unsigned SCEV ranges for tripcount (authored by SjoerdMeijer).

Changed prior to commit:
  https://reviews.llvm.org/D87608?vs=291554&id=291872#toc

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D87608/new/

https://reviews.llvm.org/D87608

Files:
  llvm/lib/Target/ARM/MVETailPredication.cpp


Index: llvm/lib/Target/ARM/MVETailPredication.cpp
===================================================================
--- llvm/lib/Target/ARM/MVETailPredication.cpp
+++ llvm/lib/Target/ARM/MVETailPredication.cpp
@@ -457,13 +457,10 @@
   //     upperbound(TC) <= UINT_MAX - VectorWidth
   //
   unsigned SizeInBits = TripCount->getType()->getScalarSizeInBits();
-  auto Diff = APInt(SizeInBits, ~0) - APInt(SizeInBits, VectorWidth);
-  uint64_t MaxMinusVW = Diff.getZExtValue();
-  // FIXME: since ranges can be negative we work with signed ranges here, but
-  // we shouldn't extract the zext'ed values for them.
-  uint64_t UpperboundTC = SE->getSignedRange(TC).getUpper().getZExtValue();
+  auto MaxMinusVW = APInt(SizeInBits, ~0) - APInt(SizeInBits, VectorWidth);
+  APInt UpperboundTC = SE->getUnsignedRangeMax(TC);
 
-  if (UpperboundTC > MaxMinusVW && !ForceTailPredication) {
+  if (UpperboundTC.ugt(MaxMinusVW) && !ForceTailPredication) {
     LLVM_DEBUG(dbgs() << "ARM TP: Overflow possible in tripcount rounding:\n";
                dbgs() << "upperbound(TC) <= UINT_MAX - VectorWidth\n";
                dbgs() << UpperboundTC << " <= " << MaxMinusVW << " == false\n";);
@@ -501,8 +498,8 @@
   auto *Ceil = SE->getUDivExpr(ECPlusVWMinus1,
       SE->getSCEV(ConstantInt::get(TripCount->getType(), VectorWidth)));
 
-  ConstantRange RangeCeil = SE->getSignedRange(Ceil) ;
-  ConstantRange RangeTC = SE->getSignedRange(TC) ;
+  ConstantRange RangeCeil = SE->getUnsignedRange(Ceil) ;
+  ConstantRange RangeTC = SE->getUnsignedRange(TC) ;
   if (!RangeTC.isSingleElement()) {
     auto ZeroRange =
         ConstantRange(APInt(TripCount->getType()->getScalarSizeInBits(), 0));


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