[llvm] 376dad7 - [SLP]Move resulting vector before inert point, if the late generated buildvector fully matched

[Alexey Bataev via llvm-commits]

Author: Alexey Bataev
Date: 2024-12-06T13:54:48-08:00
New Revision: 376dad72abb4960cd93e37e3e98de3950b5c3dfe

URL: https://github.com/llvm/llvm-project/commit/376dad72abb4960cd93e37e3e98de3950b5c3dfe
DIFF: https://github.com/llvm/llvm-project/commit/376dad72abb4960cd93e37e3e98de3950b5c3dfe.diff

LOG: [SLP]Move resulting vector before inert point, if the late generated buildvector fully matched

If the perfect diamond match was detected for the postponed buildvectors
and the vector for the previous node comes after the current node, need
to move the vector register before the current inserting point to
prevent compiler crash.

Fixes #119002

Added: 
    llvm/test/Transforms/SLPVectorizer/X86/perfect-matched-reused-bv.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 51841a842ce0b0..50590e51ae0ed7 100644
--- a/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
+++ b/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
@@ -16215,6 +16215,11 @@ BoUpSLP::vectorizeTree(const ExtraValueToDebugLocsMap &ExternallyUsedValues,
     }
     Builder.SetCurrentDebugLocation(UserI->getDebugLoc());
     Value *Vec = vectorizeTree(TE, /*PostponedPHIs=*/false);
+    if (auto *VecI = dyn_cast<Instruction>(Vec);
+        VecI && VecI->getParent() == Builder.GetInsertBlock() &&
+        Builder.GetInsertPoint()->comesBefore(VecI))
+      VecI->moveBeforePreserving(*Builder.GetInsertBlock(),
+                                 Builder.GetInsertPoint());
     if (Vec->getType() != PrevVec->getType()) {
       assert(Vec->getType()->isIntOrIntVectorTy() &&
              PrevVec->getType()->isIntOrIntVectorTy() &&

diff  --git a/llvm/test/Transforms/SLPVectorizer/X86/perfect-matched-reused-bv.ll b/llvm/test/Transforms/SLPVectorizer/X86/perfect-matched-reused-bv.ll
new file mode 100644
index 00000000000000..1053e0fc10669e
--- /dev/null
+++ b/llvm/test/Transforms/SLPVectorizer/X86/perfect-matched-reused-bv.ll
@@ -0,0 +1,42 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
+; RUN: opt -S --passes=slp-vectorizer -mtriple=x86_64-unknown-linux-gnu -mattr=+avx512f < %s | FileCheck %s
+
+define void @test() {
+; CHECK-LABEL: define void @test(
+; CHECK-SAME: ) #[[ATTR0:[0-9]+]] {
+; CHECK-NEXT:  [[BB:.*]]:
+; CHECK-NEXT:    br label %[[BB1:.*]]
+; CHECK:       [[BB1]]:
+; CHECK-NEXT:    [[TMP0:%.*]] = phi <2 x i32> [ zeroinitializer, %[[BB]] ], [ [[TMP4:%.*]], %[[BB4:.*]] ]
+; CHECK-NEXT:    [[TMP1:%.*]] = or <2 x i32> [[TMP0]], zeroinitializer
+; CHECK-NEXT:    br i1 false, label %[[BB7:.*]], label %[[BB4]]
+; CHECK:       [[BB4]]:
+; CHECK-NEXT:    [[TMP2:%.*]] = shufflevector <2 x i32> [[TMP0]], <2 x i32> <i32 0, i32 poison>, <2 x i32> <i32 2, i32 1>
+; CHECK-NEXT:    [[TMP3:%.*]] = add <2 x i32> zeroinitializer, [[TMP2]]
+; CHECK-NEXT:    [[TMP4]] = add <2 x i32> zeroinitializer, [[TMP2]]
+; CHECK-NEXT:    br i1 false, label %[[BB7]], label %[[BB1]]
+; CHECK:       [[BB7]]:
+; CHECK-NEXT:    [[TMP5:%.*]] = phi <2 x i32> [ [[TMP1]], %[[BB1]] ], [ [[TMP3]], %[[BB4]] ]
+; CHECK-NEXT:    ret void
+;
+bb:
+  br label %bb1
+
+bb1:
+  %phi = phi i32 [ 0, %bb ], [ %add6, %bb4 ]
+  %phi2 = phi i32 [ 0, %bb ], [ %add, %bb4 ]
+  %or = or i32 %phi2, 0
+  %or3 = or i32 %phi, 0
+  br i1 false, label %bb7, label %bb4
+
+bb4:
+  %add = add i32 0, 0
+  %add5 = add i32 0, 0
+  %add6 = add i32 %phi, 0
+  br i1 false, label %bb7, label %bb1
+
+bb7:
+  %phi8 = phi i32 [ %or, %bb1 ], [ %add5, %bb4 ]
+  %phi9 = phi i32 [ %or3, %bb1 ], [ %add6, %bb4 ]
+  ret void
+}