[llvm] 9400270 - [SLP]Fix comparator for vector operands of extractelements in PHICompare

[Alexey Bataev via llvm-commits]

Author: Alexey Bataev
Date: 2025-05-01T14:28:20-07:00
New Revision: 9400270449bc848fa8dd2a7575fc4fc102e34d0d

URL: https://github.com/llvm/llvm-project/commit/9400270449bc848fa8dd2a7575fc4fc102e34d0d
DIFF: https://github.com/llvm/llvm-project/commit/9400270449bc848fa8dd2a7575fc4fc102e34d0d.diff

LOG: [SLP]Fix comparator for vector operands of extractelements in PHICompare

Need to make comparator to follow strict-weak ordering to fix compiler
crashes.

Fixes #138178

Added: 
    llvm/test/Transforms/SLPVectorizer/X86/phi-comparator-fix-vec-ops-compare.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 a20bd990ded75..5df38bc96fc9c 100644
--- a/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
+++ b/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
@@ -24069,10 +24069,23 @@ bool SLPVectorizerPass::vectorizeChainsInBlock(BasicBlock *BB, BoUpSLP &R) {
             const auto *V1 = dyn_cast<Instruction>(E1->getVectorOperand());
             const auto *V2 = dyn_cast<Instruction>(E2->getVectorOperand());
             if (V1 != V2) {
-              if (!V1 || !V2)
-                continue;
-              if (V1->getParent() != V2->getParent())
-                continue;
+              if (V1 && !V2)
+                return true;
+              if (!V1 && V2)
+                return false;
+              DomTreeNodeBase<BasicBlock> *NodeI1 =
+                  DT->getNode(V1->getParent());
+              DomTreeNodeBase<BasicBlock> *NodeI2 =
+                  DT->getNode(V2->getParent());
+              if (!NodeI1)
+                return NodeI2 != nullptr;
+              if (!NodeI2)
+                return false;
+              assert((NodeI1 == NodeI2) ==
+                         (NodeI1->getDFSNumIn() == NodeI2->getDFSNumIn()) &&
+                     "Different nodes should have 
diff erent DFS numbers");
+              if (NodeI1 != NodeI2)
+                return NodeI1->getDFSNumIn() < NodeI2->getDFSNumIn();
               return V1->comesBefore(V2);
             }
             // If we have the same vector operand, try to sort by constant

diff  --git a/llvm/test/Transforms/SLPVectorizer/X86/phi-comparator-fix-vec-ops-compare.ll b/llvm/test/Transforms/SLPVectorizer/X86/phi-comparator-fix-vec-ops-compare.ll
new file mode 100644
index 0000000000000..42d3d8049a897
--- /dev/null
+++ b/llvm/test/Transforms/SLPVectorizer/X86/phi-comparator-fix-vec-ops-compare.ll
@@ -0,0 +1,46 @@
+; 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 < %s | FileCheck %s
+
+define void @test({ <2 x float>, float } %0, <2 x float> %1, i1 %2) {
+; CHECK-LABEL: define void @test(
+; CHECK-SAME: { <2 x float>, float } [[TMP0:%.*]], <2 x float> [[TMP1:%.*]], i1 [[TMP2:%.*]]) {
+; CHECK-NEXT:    [[TMP4:%.*]] = extractvalue { <2 x float>, float } [[TMP0]], 0
+; CHECK-NEXT:    [[TMP5:%.*]] = extractelement <2 x float> [[TMP4]], i64 0
+; CHECK-NEXT:    [[TMP6:%.*]] = extractelement <2 x float> [[TMP1]], i64 1
+; CHECK-NEXT:    [[TMP7:%.*]] = extractelement <2 x float> [[TMP1]], i64 0
+; CHECK-NEXT:    br i1 [[TMP2]], label %[[BB9:.*]], label %[[BB8:.*]]
+; CHECK:       [[BB8]]:
+; CHECK-NEXT:    br label %[[BB9]]
+; CHECK:       [[BB9]]:
+; CHECK-NEXT:    [[TMP10:%.*]] = phi float [ 0.000000e+00, %[[BB8]] ], [ [[TMP7]], [[TMP3:%.*]] ]
+; CHECK-NEXT:    [[TMP11:%.*]] = phi float [ 0.000000e+00, %[[BB8]] ], [ [[TMP6]], [[TMP3]] ]
+; CHECK-NEXT:    [[TMP12:%.*]] = phi float [ 0.000000e+00, %[[BB8]] ], [ [[TMP5]], [[TMP3]] ]
+; CHECK-NEXT:    [[TMP13:%.*]] = fpext float [[TMP12]] to double
+; CHECK-NEXT:    [[TMP14:%.*]] = fpext float [[TMP11]] to double
+; CHECK-NEXT:    [[TMP15:%.*]] = tail call i32 (ptr, ptr, ...) @fprintf(ptr null, ptr null, double [[TMP13]], double [[TMP14]], double 0.000000e+00)
+; CHECK-NEXT:    [[TMP16:%.*]] = fpext float [[TMP10]] to double
+; CHECK-NEXT:    [[TMP17:%.*]] = tail call i32 (ptr, ptr, ...) @fprintf(ptr null, ptr null, double 0.000000e+00, double [[TMP16]], double 0.000000e+00)
+; CHECK-NEXT:    ret void
+;
+  %4 = extractvalue { <2 x float>, float } %0, 0
+  %5 = extractelement <2 x float> %4, i64 0
+  %6 = extractelement <2 x float> %1, i64 1
+  %7 = extractelement <2 x float> %1, i64 0
+  br i1 %2, label %9, label %8
+
+8:
+  br label %9
+
+9:
+  %10 = phi float [ 0.000000e+00, %8 ], [ %7, %3 ]
+  %11 = phi float [ 0.000000e+00, %8 ], [ %6, %3 ]
+  %12 = phi float [ 0.000000e+00, %8 ], [ %5, %3 ]
+  %13 = fpext float %12 to double
+  %14 = fpext float %11 to double
+  %15 = tail call i32 (ptr, ptr, ...) @fprintf(ptr null, ptr null, double %13, double %14, double 0.000000e+00)
+  %16 = fpext float %10 to double
+  %17 = tail call i32 (ptr, ptr, ...) @fprintf(ptr null, ptr null, double 0.000000e+00, double %16, double 0.000000e+00)
+  ret void
+}
+
+declare i32 @fprintf(ptr, ptr, ...)