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[X86][DAGCombiner] Fix assertion failure in combinei64TruncSrlAdd #128194

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Merged
merged 1 commit into from
Feb 22, 2025
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[X86][DAGCombiner] Fix assertion failure in combinei64TruncSrlAdd #128194

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2 changes: 1 addition & 1 deletion llvm/lib/Target/X86/X86ISelLowering.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -53713,7 +53713,7 @@ static SDValue combinei64TruncSrlAdd(SDValue N, EVT VT, SelectionDAG &DAG,
m_ConstInt(SrlConst)))))
return SDValue();

if (SrlConst.ule(31) || AddConst.lshr(SrlConst).shl(SrlConst) != AddConst)
if (SrlConst.ule(32) || AddConst.lshr(SrlConst).shl(SrlConst) != AddConst)
return SDValue();

SDValue AddLHSSrl =
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28 changes: 28 additions & 0 deletions llvm/test/CodeGen/X86/combine-i64-trunc-srl-add.ll
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Expand Up @@ -123,3 +123,31 @@ define i32 @test_trunc_add(i64 %x) {
%conv = trunc i64 %shr to i32
ret i32 %conv
}

; Make sure we don't crash on this test case.

define i32 @pr128158(i64 %x) {
; X64-LABEL: pr128158:
; X64: # %bb.0: # %entry
; X64-NEXT: movabsq $-4294967296, %rax # imm = 0xFFFFFFFF00000000
; X64-NEXT: addq %rdi, %rax
; X64-NEXT: shrq $32, %rax
; X64-NEXT: .p2align 4
; X64-NEXT: .LBB9_1: # %for.body
; X64-NEXT: # =>This Inner Loop Header: Depth=1
; X64-NEXT: cmpl $9, %eax
; X64-NEXT: jb .LBB9_1
; X64-NEXT: # %bb.2: # %exit
; X64-NEXT: xorl %eax, %eax
; X64-NEXT: retq
entry:
br label %for.body

for.body:
%add = add i64 %x, -4294967296
%cmp = icmp ult i64 %add, 38654705664
br i1 %cmp, label %for.body, label %exit

exit:
ret i32 0
}