[SLP]Fix PR72524: "Out-of-bounds shuffle mask element" failed.

Need to check if we ran into subvector extract pattern before checking
for identity vector to avoid compiler crash.

Author: alexey-bataev

llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp

@@ -10569,8 +10569,12 @@ ResTy BoUpSLP::processBuildVector(const TreeEntry *E, Args &...Params) {
         });
     if (It == VectorizableTree.end())
       return false;
-    if (Mask.size() <= InputVF &&
-        ShuffleVectorInst::isIdentityMask(Mask, Mask.size())) {
+    int Idx;
+    if ((Mask.size() < InputVF &&
+         ShuffleVectorInst::isExtractSubvectorMask(Mask, InputVF, Idx) &&
+         Idx == 0) ||
+        (Mask.size() == InputVF &&
+         ShuffleVectorInst::isIdentityMask(Mask, Mask.size()))) {
       std::iota(Mask.begin(), Mask.end(), 0);
     } else {
       unsigned I =

llvm/test/Transforms/SLPVectorizer/X86/extract-subvector-long-input.ll

@@ -0,0 +1,85 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 4
+; RUN: opt -passes=slp-vectorizer -S -slp-threshold=-99999 -mtriple=x86_64-unknown-linux-gnu < %s | FileCheck %s
+
+define void @test() {
+; CHECK-LABEL: define void @test() {
+; CHECK-NEXT:  bb:
+; CHECK-NEXT:    br label [[BB1:%.*]]
+; CHECK:       bb1:
+; CHECK-NEXT:    [[TMP0:%.*]] = phi <8 x i32> [ poison, [[BB10:%.*]] ], [ zeroinitializer, [[BB:%.*]] ]
+; CHECK-NEXT:    [[TMP1:%.*]] = shufflevector <8 x i32> [[TMP0]], <8 x i32> poison, <2 x i32> <i32 6, i32 6>
+; CHECK-NEXT:    switch i32 0, label [[BB16:%.*]] [
+; CHECK-NEXT:      i32 0, label [[BB14:%.*]]
+; CHECK-NEXT:      i32 1, label [[BB11:%.*]]
+; CHECK-NEXT:    ]
+; CHECK:       bb9:
+; CHECK-NEXT:    br label [[BB11]]
+; CHECK:       bb10:
+; CHECK-NEXT:    br label [[BB1]]
+; CHECK:       bb11:
+; CHECK-NEXT:    [[TMP2:%.*]] = phi <2 x i32> [ poison, [[BB9:%.*]] ], [ [[TMP1]], [[BB1]] ]
+; CHECK-NEXT:    ret void
+; CHECK:       bb14:
+; CHECK-NEXT:    ret void
+; CHECK:       bb15:
+; CHECK-NEXT:    ret void
+; CHECK:       bb16:
+; CHECK-NEXT:    [[TMP3:%.*]] = phi <8 x i32> [ [[TMP0]], [[BB1]] ], [ poison, [[BB25:%.*]] ]
+; CHECK-NEXT:    ret void
+; CHECK:       bb25:
+; CHECK-NEXT:    switch i32 0, label [[BB16]] [
+; CHECK-NEXT:      i32 0, label [[BB14]]
+; CHECK-NEXT:      i32 1, label [[BB15:%.*]]
+; CHECK-NEXT:    ]
+;
+bb:
+  br label %bb1
+
+bb1:
+  %phi = phi i32 [ 0, %bb10 ], [ 0, %bb ]
+  %phi2 = phi i32 [ 0, %bb10 ], [ 0, %bb ]
+  %phi3 = phi i32 [ 0, %bb10 ], [ 0, %bb ]
+  %phi4 = phi i32 [ 0, %bb10 ], [ 0, %bb ]
+  %phi5 = phi i32 [ 0, %bb10 ], [ 0, %bb ]
+  %phi6 = phi i32 [ 0, %bb10 ], [ 0, %bb ]
+  %phi7 = phi i32 [ 0, %bb10 ], [ 0, %bb ]
+  %phi8 = phi i32 [ 0, %bb10 ], [ 0, %bb ]
+  switch i32 0, label %bb16 [
+  i32 0, label %bb14
+  i32 1, label %bb11
+  ]
+
+bb9:
+  br label %bb11
+
+bb10:
+  br label %bb1
+
+bb11:
+  %phi12 = phi i32 [ 0, %bb9 ], [ %phi7, %bb1 ]
+  %phi13 = phi i32 [ 0, %bb9 ], [ undef, %bb1 ]
+  ret void
+
+bb14:
+  ret void
+
+bb15:
+  ret void
+
+bb16:
+  %phi17 = phi i32 [ %phi, %bb1 ], [ 0, %bb25 ]
+  %phi18 = phi i32 [ %phi2, %bb1 ], [ 0, %bb25 ]
+  %phi19 = phi i32 [ %phi3, %bb1 ], [ 0, %bb25 ]
+  %phi20 = phi i32 [ %phi4, %bb1 ], [ 0, %bb25 ]
+  %phi21 = phi i32 [ %phi5, %bb1 ], [ 0, %bb25 ]
+  %phi22 = phi i32 [ %phi6, %bb1 ], [ 0, %bb25 ]
+  %phi23 = phi i32 [ %phi7, %bb1 ], [ 0, %bb25 ]
+  %phi24 = phi i32 [ %phi8, %bb1 ], [ 0, %bb25 ]
+  ret void
+
+bb25:
+  switch i32 0, label %bb16 [
+  i32 0, label %bb14
+  i32 1, label %bb15
+  ]
+}