[llvm] 7b1cb47 - [IR] Bail out for scalable vectors in ShuffleVectorInst::isConcat

[Cullen Rhodes via llvm-commits]

Author: Cullen Rhodes
Date: 2020-12-07T10:48:35Z
New Revision: 7b1cb4715063679531e51127eee869cd03df88da

URL: https://github.com/llvm/llvm-project/commit/7b1cb4715063679531e51127eee869cd03df88da
DIFF: https://github.com/llvm/llvm-project/commit/7b1cb4715063679531e51127eee869cd03df88da.diff

LOG: [IR] Bail out for scalable vectors in ShuffleVectorInst::isConcat

Shuffle mask for concat can't be expressed for scalable vectors, so we
should bail out. A test has been added that previously crashed, also
tested isIdentityWithPadding and isIdentityWithExtract where we already
bail out.

Reviewed By: sdesmalen

Differential Revision: https://reviews.llvm.org/D92475

Added: 
    

Modified: 
    llvm/lib/IR/Instructions.cpp
    llvm/unittests/IR/InstructionsTest.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/lib/IR/Instructions.cpp b/llvm/lib/IR/Instructions.cpp
index 10427b22d5d7..5de1addabbe2 100644
--- a/llvm/lib/IR/Instructions.cpp
+++ b/llvm/lib/IR/Instructions.cpp
@@ -2274,6 +2274,11 @@ bool ShuffleVectorInst::isConcat() const {
       isa<UndefValue>(Op<2>()))
     return false;
 
+  // FIXME: Not currently possible to express a shuffle mask for a scalable
+  // vector for this case.
+  if (isa<ScalableVectorType>(getType()))
+    return false;
+
   int NumOpElts = cast<FixedVectorType>(Op<0>()->getType())->getNumElements();
   int NumMaskElts = cast<FixedVectorType>(getType())->getNumElements();
   if (NumMaskElts != NumOpElts * 2)

diff  --git a/llvm/unittests/IR/InstructionsTest.cpp b/llvm/unittests/IR/InstructionsTest.cpp
index 09260d347840..2c67ff4286e7 100644
--- a/llvm/unittests/IR/InstructionsTest.cpp
+++ b/llvm/unittests/IR/InstructionsTest.cpp
@@ -1096,6 +1096,17 @@ TEST(InstructionsTest, ShuffleMaskQueries) {
   EXPECT_TRUE(Id14->changesLength());
   EXPECT_TRUE(Id14->increasesLength());
   delete Id14;
+
+  // Not possible to express these masks for scalable vectors, make sure we
+  // don't crash.
+  ShuffleVectorInst *Id15 =
+      new ShuffleVectorInst(Constant::getAllOnesValue(VScaleV2Int32Ty),
+                            Constant::getNullValue(VScaleV2Int32Ty),
+                            Constant::getNullValue(VScaleV2Int32Ty));
+  EXPECT_FALSE(Id15->isIdentityWithPadding());
+  EXPECT_FALSE(Id15->isIdentityWithExtract());
+  EXPECT_FALSE(Id15->isConcat());
+  delete Id15;
 }
 
 TEST(InstructionsTest, GetSplat) {