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[RISCV] Don't select sh{1,2,3}add if shl doesn't have one use #143351

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Merged
merged 2 commits into from
Jun 10, 2025
Merged

[RISCV] Don't select sh{1,2,3}add if shl doesn't have one use #143351

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ac96a84
[RISCV] Don't select sh{1,2,3}add if shl doesn't have one use
tclin914 Jun 9, 2025
b5593e0
Use m_OneUse and m_Shl instead
tclin914 Jun 10, 2025
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2 changes: 1 addition & 1 deletion llvm/lib/Target/RISCV/RISCVISelLowering.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -14884,7 +14884,7 @@ static SDValue combineShlAddIAddImpl(SDNode *N, SDValue AddI, SDValue Other,
return SDValue();

APInt VShift;
if (!sd_match(SHLVal, m_BinOp(ISD::SHL, m_Value(), m_ConstInt(VShift))))
if (!sd_match(SHLVal, m_OneUse(m_Shl(m_Value(), m_ConstInt(VShift)))))
return SDValue();

if (VShift.slt(1) || VShift.sgt(3))
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23 changes: 11 additions & 12 deletions llvm/test/CodeGen/RISCV/reassoc-shl-addi-add.ll
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Expand Up @@ -8,10 +8,10 @@ declare i32 @callee(i32 noundef, i32 noundef, i32 noundef, i32 noundef)
define void @t1(i32 noundef %a, i32 noundef %b, i32 noundef %c, i32 noundef %d) #0 {
; CHECK-LABEL: t1:
; CHECK: # %bb.0: # %entry
; CHECK-NEXT: sh2add a2, a0, a2
; CHECK-NEXT: sh2add a1, a0, a1
; CHECK-NEXT: addi a1, a1, 45
; CHECK-NEXT: addi a2, a2, 45
; CHECK-NEXT: slli a4, a0, 2
; CHECK-NEXT: addi a4, a4, 45
; CHECK-NEXT: add a1, a4, a1
; CHECK-NEXT: add a2, a4, a2
; CHECK-NEXT: sh2add a3, a0, a3
; CHECK-NEXT: mv a0, a1
; CHECK-NEXT: tail callee
Expand Down Expand Up @@ -133,12 +133,11 @@ entry:
define void @t8(i32 noundef %a, i32 noundef %b, i32 noundef %c, i32 noundef %d) #0 {
; CHECK-LABEL: t8:
; CHECK: # %bb.0: # %entry
; CHECK-NEXT: sh3add a2, a0, a2
; CHECK-NEXT: sh3add a1, a0, a1
; CHECK-NEXT: lui a4, 1
; CHECK-NEXT: addi a4, a4, 1307
; CHECK-NEXT: add a1, a1, a4
; CHECK-NEXT: add a2, a2, a4
; CHECK-NEXT: sh3add a4, a0, a4
; CHECK-NEXT: add a1, a4, a1
; CHECK-NEXT: add a2, a4, a2
; CHECK-NEXT: sh3add a3, a0, a3
; CHECK-NEXT: mv a0, a1
; CHECK-NEXT: tail callee
Expand All @@ -155,10 +154,10 @@ entry:
define void @t9(i32 noundef %a, i32 noundef %b, i32 noundef %c, i32 noundef %d) #0 {
; CHECK-LABEL: t9:
; CHECK: # %bb.0: # %entry
; CHECK-NEXT: sh2add a2, a0, a2
; CHECK-NEXT: sh2add a1, a0, a1
; CHECK-NEXT: addi a1, a1, -42
; CHECK-NEXT: addi a2, a2, -42
; CHECK-NEXT: slli a4, a0, 2
; CHECK-NEXT: addi a4, a4, -42
; CHECK-NEXT: add a1, a4, a1
; CHECK-NEXT: add a2, a4, a2
; CHECK-NEXT: sh2add a3, a0, a3
; CHECK-NEXT: mv a0, a1
; CHECK-NEXT: tail callee
Expand Down
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