[llvm] 414abff - [SLP]Fix PR52090: clang crashes: Assertion `Index < Length && "Invalid index!"' failed.

[Alexey Bataev via llvm-commits]

Author: Alexey Bataev
Date: 2021-10-14T14:26:29-07:00
New Revision: 414abff1fe8ac3d5874f9b838cb59a3300b3e475

URL: https://github.com/llvm/llvm-project/commit/414abff1fe8ac3d5874f9b838cb59a3300b3e475
DIFF: https://github.com/llvm/llvm-project/commit/414abff1fe8ac3d5874f9b838cb59a3300b3e475.diff

LOG: [SLP]Fix PR52090: clang crashes: Assertion `Index < Length && "Invalid index!"' failed.

Need to check that either Idx is UndefMaskElem and value is UndefValue
or Idx is valid and value is the same as the scalar value in the node.

Differential Revision: https://reviews.llvm.org/D111802

Added: 
    llvm/test/Transforms/SLPVectorizer/X86/crash_undef_mask_elem.ll

Modified: 
    llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp b/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
index bdf3f44742bdd..9a69ddbad5d58 100644
--- a/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
+++ b/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
@@ -1640,9 +1640,12 @@ class BoUpSLP {
         if (Mask.size() != VL.size() && VL.size() == Scalars.size())
           return std::equal(VL.begin(), VL.end(), Scalars.begin());
         return VL.size() == Mask.size() &&
-               std::equal(
-                   VL.begin(), VL.end(), Mask.begin(),
-                   [Scalars](Value *V, int Idx) { return V == Scalars[Idx]; });
+               std::equal(VL.begin(), VL.end(), Mask.begin(),
+                          [Scalars](Value *V, int Idx) {
+                            return (isa<UndefValue>(V) &&
+                                    Idx == UndefMaskElem) ||
+                                   (Idx != UndefMaskElem && V == Scalars[Idx]);
+                          });
       };
       if (!ReorderIndices.empty()) {
         // TODO: implement matching if the nodes are just reordered, still can

diff  --git a/llvm/test/Transforms/SLPVectorizer/X86/crash_undef_mask_elem.ll b/llvm/test/Transforms/SLPVectorizer/X86/crash_undef_mask_elem.ll
new file mode 100644
index 0000000000000..0561aa8309fcf
--- /dev/null
+++ b/llvm/test/Transforms/SLPVectorizer/X86/crash_undef_mask_elem.ll
@@ -0,0 +1,47 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt -slp-vectorizer -S -o - -mtriple=x86_64 < %s | FileCheck %s
+
+define void @main(i32 %x, i1 %b) {
+; CHECK-LABEL: @main(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br i1 [[B:%.*]], label [[L3:%.*]], label [[L1_THREAD:%.*]]
+; CHECK:       L1:
+; CHECK-NEXT:    br label [[L3]]
+; CHECK:       L1.thread:
+; CHECK-NEXT:    br label [[L3]]
+; CHECK:       L3:
+; CHECK-NEXT:    [[DOTPR21:%.*]] = phi i32 [ [[X:%.*]], [[ENTRY:%.*]] ], [ [[DOTPR21]], [[L1:%.*]] ], [ [[X]], [[L1_THREAD]] ]
+; CHECK-NEXT:    [[DOTOLD_PR15:%.*]] = phi i32 [ [[X]], [[ENTRY]] ], [ 0, [[L1]] ], [ [[X]], [[L1_THREAD]] ]
+; CHECK-NEXT:    [[H_1:%.*]] = phi i32 [ undef, [[ENTRY]] ], [ undef, [[L1]] ], [ undef, [[L1_THREAD]] ]
+; CHECK-NEXT:    [[I_2:%.*]] = phi i32 [ 1, [[ENTRY]] ], [ [[I_2]], [[L1]] ], [ 1, [[L1_THREAD]] ]
+; CHECK-NEXT:    [[K_3:%.*]] = phi i32 [ 0, [[ENTRY]] ], [ [[I_2]], [[L1]] ], [ 1, [[L1_THREAD]] ]
+; CHECK-NEXT:    [[G_1:%.*]] = phi i32 [ undef, [[ENTRY]] ], [ [[O_1:%.*]], [[L1]] ], [ undef, [[L1_THREAD]] ]
+; CHECK-NEXT:    [[M_3:%.*]] = phi i32 [ undef, [[ENTRY]] ], [ [[I_2]], [[L1]] ], [ 1, [[L1_THREAD]] ]
+; CHECK-NEXT:    [[O_1]] = phi i32 [ undef, [[ENTRY]] ], [ [[O_1]], [[L1]] ], [ undef, [[L1_THREAD]] ]
+; CHECK-NEXT:    br label [[L4:%.*]]
+; CHECK:       L4:
+; CHECK-NEXT:    br label [[L1]]
+;
+entry:
+  br i1 %b, label %L3, label %L1.thread
+
+L1:
+  br label %L3
+
+L1.thread:
+  br label %L3
+
+L3:
+  %.pr21 = phi i32 [ %x, %entry ], [ %.pr21, %L1 ], [ %x, %L1.thread ]
+  %.old.pr15 = phi i32 [ %x, %entry ], [ 0, %L1 ], [ %x, %L1.thread ]
+  %h.1 = phi i32 [ undef, %entry ], [ undef, %L1 ], [ undef, %L1.thread ]
+  %i.2 = phi i32 [ 1, %entry ], [ %i.2, %L1 ], [ 1, %L1.thread ]
+  %k.3 = phi i32 [ 0, %entry ], [ %i.2, %L1 ], [ 1, %L1.thread ]
+  %g.1 = phi i32 [ undef, %entry ], [ %o.1, %L1 ], [ undef, %L1.thread ]
+  %m.3 = phi i32 [ undef, %entry ], [ %i.2, %L1 ], [ 1, %L1.thread ]
+  %o.1 = phi i32 [ undef, %entry ], [ %o.1, %L1 ], [ undef, %L1.thread ]
+  br label %L4
+
+L4:
+  br label %L1
+}