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Fix potential crash in SLPVectorizer caused by missing check #95937

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Jul 2, 2024
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Fix potential crash in SLPVectorizer caused by missing check #95937

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ede8689
Fix potential crash in SLPVectorizer caused by missing null check
gbaraldi Jun 18, 2024
fd86e2d
Merge branch 'main' into gb/fix-null-deref
gbaraldi Jun 25, 2024
86deae0
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gbaraldi Jun 26, 2024
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2 changes: 1 addition & 1 deletion llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
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Expand Up @@ -835,7 +835,7 @@ static InstructionsState getSameOpcode(ArrayRef<Value *> VL,
auto *CallBase = cast<CallInst>(IBase);
if (Call->getCalledFunction() != CallBase->getCalledFunction())
return InstructionsState(VL[BaseIndex], nullptr, nullptr);
if (Call->hasOperandBundles() &&
if (Call->hasOperandBundles() && CallBase->hasOperandBundles() &&
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Suggested change
if (Call->hasOperandBundles() && CallBase->hasOperandBundles() &&
if (Call->hasOperandBundles() && (!CallBase->hasOperandBundles() ||

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Is the idea that if CallBase doesn't have an operandBundle is ignored?

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The idea is that two calls are incompatible if they have different operand bundles. If one has a bundle but another does not, they are still incompatible.

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Right, but if we have that change we will return true no? i.e Call->hasOperandBundles() == true and !CallBase->hasOperandBundles() == true will enter the branch. Unless I misunderstood your change

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Yes, it will execute return. And that's fine, this return returns false, not true

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Oh ok, We just don't want a fallthrough

!std::equal(Call->op_begin() + Call->getBundleOperandsStartIndex(),
Call->op_begin() + Call->getBundleOperandsEndIndex(),
CallBase->op_begin() +
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43 changes: 43 additions & 0 deletions llvm/test/Transforms/SLPVectorizer/AArch64/uselistorder.ll
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@@ -0,0 +1,43 @@
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt < %s -passes=slp-vectorizer -S -pass-remarks-missed=slp-vectorizer 2>&1 | FileCheck %s

target datalayout = "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128"
target triple = "aarch64-unknown-linux-gnu"

; This test has UB but the crash in #95016 only happens with it
define void @uselistorder_test() {
; CHECK-LABEL: @uselistorder_test(
; CHECK-NEXT: [[TMP1:%.*]] = insertelement <2 x double> poison, double 0.000000e+00, i32 0
; CHECK-NEXT: [[TMP2:%.*]] = insertelement <2 x double> [[TMP1]], double 0.000000e+00, i32 1
; CHECK-NEXT: [[TMP3:%.*]] = fadd <2 x double> [[TMP2]], zeroinitializer
; CHECK-NEXT: [[TMP4:%.*]] = fmul <2 x double> zeroinitializer, [[TMP3]]
; CHECK-NEXT: [[TMP5:%.*]] = fmul <2 x double> [[TMP4]], zeroinitializer
; CHECK-NEXT: [[TMP6:%.*]] = select <2 x i1> zeroinitializer, <2 x double> zeroinitializer, <2 x double> [[TMP5]]
; CHECK-NEXT: [[TMP7:%.*]] = fmul <2 x double> [[TMP6]], zeroinitializer
; CHECK-NEXT: [[TMP8:%.*]] = fadd <2 x double> [[TMP7]], zeroinitializer
; CHECK-NEXT: store <2 x double> [[TMP8]], ptr null, align 8
; CHECK-NEXT: ret void
;
%max1 = call double @llvm.maximum.f64(double 0.000000e+00, double 0.000000e+00) [ "a_list"(ptr null) ]
%add1 = fadd double %max1, 0.000000e+00
%mul1 = fmul double 0.000000e+00, %add1
%mul2 = fmul double %mul1, 0.000000e+00
%sel1 = select i1 false, double 0.000000e+00, double %mul2
%max2 = call double @llvm.maximum.f64(double 0.000000e+00, double 0.000000e+00)
%add2 = fadd double %max2, 0.000000e+00
%mul3 = fmul double 0.000000e+00, %add2
%mul4 = fmul double %mul3, 0.000000e+00
%sel2 = select i1 false, double 0.000000e+00, double %mul4
%mul5 = fmul double %sel2, 0.000000e+00
%add3 = fadd double 0.000000e+00, %mul5
%gep1 = getelementptr { double, [1 x [2 x double]] }, ptr null, i64 0, i32 1
store double %add3, ptr %gep1, align 8
%mul6 = fmul double %sel1, 0.000000e+00
%add4 = fadd double %mul6, 0.000000e+00
store double %add4, ptr null, align 8
ret void
}

declare double @llvm.maximum.f64(double, double) #0

attributes #0 = { nocallback nofree nosync nounwind speculatable willreturn memory(none) }
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