[SLP]Fix PR62665: compiler crash when trying to access non-existing mask

element.

Need to check at first if the SubMask element is PoisonMaskElem to avoid
compiler crash.

diff --git a/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp b/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
index 75780ca..c379c6d 100644 (file)
--- a/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
+++ b/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
@@ -961,9 +961,9 @@ static void addMask(SmallVectorImpl<int> &Mask, ArrayRef<int> SubMask,
   SmallVector<int> NewMask(SubMask.size(), PoisonMaskElem);
   int TermValue = std::min(Mask.size(), SubMask.size());
   for (int I = 0, E = SubMask.size(); I < E; ++I) {
-    if ((!ExtendingManyInputs &&
-         (SubMask[I] >= TermValue || Mask[SubMask[I]] >= TermValue)) ||
-        SubMask[I] == PoisonMaskElem)
+    if (SubMask[I] == PoisonMaskElem ||
+        (!ExtendingManyInputs &&
+         (SubMask[I] >= TermValue || Mask[SubMask[I]] >= TermValue)))
       continue;
     NewMask[I] = Mask[SubMask[I]];
   }

diff --git a/llvm/test/Transforms/SLPVectorizer/X86/poison-element-shuffle.ll b/llvm/test/Transforms/SLPVectorizer/X86/poison-element-shuffle.ll
new file mode 100644 (file)
index 0000000..32ae214
--- /dev/null
+++ b/llvm/test/Transforms/SLPVectorizer/X86/poison-element-shuffle.ll
@@ -0,0 +1,48 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 2
+; RUN: opt --passes=slp-vectorizer -S -mtriple=x86_64-unknown-linux-gnu %s -o - | FileCheck %s
+
+define i32 @main(i32 %v) {
+; CHECK-LABEL: define i32 @main
+; CHECK-SAME: (i32 [[V:%.*]]) {
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[V1:%.*]] = sext i1 false to i32
+; CHECK-NEXT:    br i1 false, label [[IF_END11:%.*]], label [[Q41:%.*]]
+; CHECK:       if.end11:
+; CHECK-NEXT:    [[P1:%.*]] = phi i32 [ [[V1]], [[ENTRY:%.*]] ], [ [[P6:%.*]], [[Q41]] ], [ [[V]], [[IF_END11]] ]
+; CHECK-NEXT:    [[P2:%.*]] = phi i32 [ [[V1]], [[ENTRY]] ], [ [[P6]], [[Q41]] ], [ [[V]], [[IF_END11]] ]
+; CHECK-NEXT:    [[P3:%.*]] = phi i32 [ [[V1]], [[ENTRY]] ], [ [[P6]], [[Q41]] ], [ 0, [[IF_END11]] ]
+; CHECK-NEXT:    [[P4:%.*]] = phi i32 [ [[V1]], [[ENTRY]] ], [ [[P6]], [[Q41]] ], [ 0, [[IF_END11]] ]
+; CHECK-NEXT:    [[P5:%.*]] = phi i32 [ [[V1]], [[ENTRY]] ], [ [[P6]], [[Q41]] ], [ 0, [[IF_END11]] ]
+; CHECK-NEXT:    [[S_14:%.*]] = phi i32 [ 0, [[ENTRY]] ], [ [[S_3:%.*]], [[Q41]] ], [ [[V]], [[IF_END11]] ]
+; CHECK-NEXT:    [[V_1:%.*]] = phi i32 [ undef, [[ENTRY]] ], [ [[V_4:%.*]], [[Q41]] ], [ 0, [[IF_END11]] ]
+; CHECK-NEXT:    [[Q_1:%.*]] = phi i32 [ 0, [[ENTRY]] ], [ [[Q_2:%.*]], [[Q41]] ], [ 0, [[IF_END11]] ]
+; CHECK-NEXT:    br i1 false, label [[Q41]], label [[IF_END11]]
+; CHECK:       q41:
+; CHECK-NEXT:    [[P6]] = phi i32 [ [[V]], [[ENTRY]] ], [ 0, [[IF_END11]] ]
+; CHECK-NEXT:    [[S_3]] = phi i32 [ undef, [[ENTRY]] ], [ 0, [[IF_END11]] ]
+; CHECK-NEXT:    [[V_4]] = phi i32 [ undef, [[ENTRY]] ], [ 0, [[IF_END11]] ]
+; CHECK-NEXT:    [[Q_2]] = phi i32 [ undef, [[ENTRY]] ], [ 0, [[IF_END11]] ]
+; CHECK-NEXT:    br label [[IF_END11]]
+;
+entry:
+  %v1 = sext i1 false to i32
+  br i1 false, label %if.end11, label %q41
+
+if.end11:
+  %p1 = phi i32 [ %v1, %entry ], [ %p6, %q41 ], [ %v, %if.end11 ]
+  %p2 = phi i32 [ %v1, %entry ], [ %p6, %q41 ], [ %v, %if.end11 ]
+  %p3 = phi i32 [ %v1, %entry ], [ %p6, %q41 ], [ 0, %if.end11 ]
+  %p4 = phi i32 [ %v1, %entry ], [ %p6, %q41 ], [ 0, %if.end11 ]
+  %p5 = phi i32 [ %v1, %entry ], [ %p6, %q41 ], [ 0, %if.end11 ]
+  %s.14 = phi i32 [ 0, %entry ], [ %s.3, %q41 ], [ %v, %if.end11 ]
+  %v.1 = phi i32 [ undef, %entry ], [ %v.4, %q41 ], [ 0, %if.end11 ]
+  %q.1 = phi i32 [ 0, %entry ], [ %q.2, %q41 ], [ 0, %if.end11 ]
+  br i1 false, label %q41, label %if.end11
+
+q41:
+  %p6 = phi i32 [ %v, %entry ], [ 0, %if.end11 ]
+  %s.3 = phi i32 [ undef, %entry ], [ 0, %if.end11 ]
+  %v.4 = phi i32 [ undef, %entry ], [ 0, %if.end11 ]
+  %q.2 = phi i32 [ undef, %entry ], [ 0, %if.end11 ]
+  br label %if.end11
+}